Home

EMC2 User Manual short - link here to our old website

Contents

1. e ee 4 4 1 Installing the components lt ss esascs daros daa a e 4 4 2 Connecting pins with signals en 4 4 3 Setting up realtime execution threads and functions 4 5 Taking a closer look with halscope 45 1 Starting Helscope oc epia a EMER RAR RR EER Oe ee 4 5 2 Hooking up the scope probes 2 2 ee 4 5 3 Capturing our first waveforms coco 6 48 64 he 0 Raa RE aieu yant 454 Vertical Adjustment cios a a ee ee A La TOS a RRA ROE RARE EE REGED ESE a a 4 5 6 Horizontal Adjustments c s ca cs be ee ee ee es Lar More Channels sa abe Ra eR RO eR RG ee wo ee Ill Using EMC2 5 Using The TKEMC Graphical Interface 28 28 28 29 29 29 29 29 30 30 31 32 33 33 33 33 34 34 34 35 36 37 38 38 38 39 39 42 42 43 44 46 46 46 46 49 50 51 51 53 54 55 57 CONTENTS 6 Using The MINI Graphical Interface 6 1 TODA fie cio A wr ee a a A a a i CS PCE NOE ee is ek eae Be Bee ee Oe Be OR we we eM de a Go Wien Bars a k a ala RA we Ge ee a ee Be aa es ae Ge a EE eA 6 Control Bitton Bar ke ae dia aa baw Shwe we eee a Dee ee 6 4 3 6 4 4 6 4 5 6 4 6 MDI obs ke ROR dera REE SSE SRE OS OR RARE HEHE EYE DRS a FEEDHOLD CONTINUE 0 eee ee ee ee SBIR es a At a ae BR aS RGN Ea ES ae ES Bee a o ts Sk AE 65 LetColumt coro Wa we a a a ee Ww a ea we de a 6 5 1 6 5 2 6
2. 7 1 7 Tool Changer A machining center has a mechanism for changing tools fixed in tool holders between the spindle and the tool carousel 7 1 8 Message Display A machining center has a device that can display messages 7 1 9 Feed and Speed Override Switches A machining center has separate feed and speed override switches which let the operator specify that the actual feed rate or spindle speed used in machining should be some percentage of the programmed rate See Section 7 3 1 7 1 10 Block Delete Switch A machining center has a block delete switch See Section 7 3 2 7 1 11 Optional Program Stop Switch A machining center has an optional program stop switch See Section 7 3 3 7 2 Control and Data Components 7 2 1 Linear Axes The X Y and Z axes form a standard right handed coordinate system of orthogonal linear axes Positions of the three linear motion mechanisms are expressed using coordinates on these axes CHAPTER 7 MACHINING CENTER OVERVIEW 71 7 2 2 Rotational Axes The rotational axes are measured in degrees as wrapped linear axes in which the direction of positive rotation is counterclockwise when viewed from the positive end of the corresponding X Y or Z axis By wrapped linear axis we mean one on which the angular position increases without limit goes towards plus infinity as the axis turns counterclockwise and deceases without limit goes towards minus infinity as the axis turns clockwise Wr
3. The editor is rather limited compared to many modern text editors It does not have undo nor paste between windows with the clipboard These were eliminated because of interaction with a running program Future releases will replace these functions so that it will work the way you ve come to expect from a text editor It is included because it has the rather nice feature of being able to number and renumber lines in the way that the interpreter expects of a file It will also allow you to cut and paste from one part of a file to another In addition it will allow you to save your changes and submit them to the EMC interpreter with the same menu click You can work on a file in here for a while and then save and load if the EMC is in Auto mode If you have been running a file and find that you need to edit it that file will be placed in the editor when you click on the editor button on the top menu 6 6 2 Backplot Display Backplot Backplot will show the tool path that can be viewed from a chosen direction 3 D is the default Other choices and controls are displayed along the top and right side of the pop in If you are in the middle of a cut when you press one of these control buttons the machine will pause long enough to re compute the view CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 66 x Y X Z Y 2 3D Hide Setup ni 1 Reset Figure 6 6 Mini s Backplotter Along the right side of the pop in there is a sma
4. 16 1 Introduction You have seen how handy a tool length offset can be Having this allows the programmer to ignore the actual tool length when writing a part program In the same way it is really nice to be able to find a prominent part of a casting or block of material and work a program from that point rather than having to take account of the location at which the casting or block will be held during the machining This chapter introduces you to offsets as they are used by the EMC These include e machine coordinates G53 e nine offsets G54 G59 3 e a set of global offsets G92 16 2 The Machine Position Command G53 Regardless of any offsets that may be in effect putting a G53 in a block of code tells the interpreter to go to the real or absolute axis positions commanded in the block For example g53 g0 x0 yO zO will get you to the actual position where these three axes are zero You might use a command like this if you have a favorite position for tool changes or if your machine has an auto tool changer You might also use this command to get the tool out of the way so that you can rotate or change a part in a vice G53 is not a modal command It must be used on each line where motion based upon absolute machine position is desired 16 3 Fixture Offsets G54 G59 3 Work or fixture offset are used to make a part home that is different from the absolute machine coordinate system This allows the part programmer to set up home
5. Jon Elson s Example All further system specific information refers to NIST s EMC program but much of it applies to most modern CNC controls My method of checking these programs is to first select tool zero which always has a diameter of zero so offset commands are essentially ignored Then I tape a sheet of paper to a piece of material that sits level in my vise as a sort of platen I install a spring loaded pen in the spindle This is a standard ballpoint pen refill cartridge made of metal in a 1 2 diameter steel housing It has a spring that loads the pen against the front and a collet at the front that allows the pen to retract against the spring but keeps it centered within a few thousandths of an inch I run the program with tool zero selected and it draws a line at the actual part s outline see figure below Then I select a tool with the diameter of the tool I intend to use and run the program again Note that Z coordinates in the program may need to be changed to prevent plunging the pen through the platen Now I get to see whether the G41 or G42 compensation that I specified will cut on the desired side of the part If it doesn t I then edit the opposite compensation command into the program and try again Now with the tool on the correct side of the work you get to see if there are any places where the tool is too fat to fit in a concave part of the surface My old Allen Bradley 7320 was pretty forgiving on th
6. _ jog the active axis in the minus direction jog the active axis in the plus direction Home home selected axis il toggle through jog increments The following only work with a machine using auxiliary I O b take spindle brake off Alt b put spindle brake on 6 7 3 Auto Mode 1 9 0 set feed override to 10 90 O is 100 set feed override to O or feedhold o O open a program r R run an opened program p P pause an executing program s S resume a paused program a A step one line in a paused program 6 8 Misc One of the features of Mini is that it displays any axis above number 2 as a rotary and will display degree units for it It also converts to degree units for incremental jogs when a rotary axis has the focus Chapter 7 Machining Center Overview This section gives a brief description of how a machining center is viewed from the input and output ends of the Interpreter It is assumed the reader is already familiar with machining centers Both the RS274 NGC input language and the output canonical machining functions have a view of 1 mechanical components of a machining center being controlled and 2 what activities of the machining center may be controlled and what data is used in control The view here includes some items that a given machining center may not have such as a pallet shuttle The RS274 NGC language and canonical machining functions may be used with such a machine provided that no NC program used with the
7. e the P number does not evaluate to an integer in the range 1 to 9 If origin offsets made by G92 or G92 3 were in effect before G10 is used they will continue to be in effect afterwards The coordinate system whose origin is set by a G10 command may be active or inactive at the time the G10 is executed Example G10 L2 Pl x 3 5 y 17 2 sets the origin of the first coordinate system the one selected by G54 to a point where X is 3 5 and Y is 17 2 in absolute coordinates The Z coordinate of the origin and the coordinates for any rotational axes are whatever those coordinates of the origin were before the line was executed 9 7 G17 G18 G19 Plane Selection Program G17 to select the XY plane G18 to select the XZ plane or G19 to select the YZ plane The effects of having a plane selected are discussed in Section 9 3 and Section 9 17 9 8 G21 G21 Length Units Program G20 to use inches for length units Program G21 to use millimeters It is usually a good idea to program either G20 or G21 near the beginning of a program before any motion occurs and not to use either one anywhere else in the program It is the responsibility of the user to be sure all numbers are appropriate for use with the current length units 9 9 G28 G30 Return to Home Two home positions are defined by parameters 5161 5166 for G28 and parameters 5181 5186 for G30 The parameter values are in terms of the absolute coordinate system but are in unspecified
8. 21 21 21 22 22 23 25 25 CONTENTS 3 9 HAL componens as bk PR RP RR ER A ee 3 3 1 External programs with HAL hooks 2 2 02 0 00000004 S32 Internal Components ss sora eee es Re RAR REDRESS g 3 0 0 Hardware HIVES o scoe se a aa a A a ee Seo DAGES ESE 3 4 Tinkertoys Erector Sets Legos and the HAL ea TOWED fae eee ae EO OEE EDR RE Oa e a ee ww SAD Erector Bete daa hoe a aa a a Ra ee amp ved TEOS ereere Sok ar BoB wR Gr ioe a atc ar SoBe ark Sw Bee A 3 4 4 A Lego Example 2 bec ov ea EON ee Ra EON ee Peas ae Se ws A aS So Timing issues IR HAL 6 6 eee Rae ae PARA Aw Ra A A a we oe wg 3 6 Dynamic Linking and Configuration eee ee ee eee 4 HAL Tutorial 4 1 Before We Stat se eee OR EEA Ee ee EO AIL OLOR a ae See A OE SN Se See ae HG am oS LL 2 ROO Primes o ok AA CEES ES GHEE de e ES 41 3 The RTAPI environment oe al aw a ee Bee da ee Kaw E A e a 12 A Simple Example oo ai a a AA A A A ae AL e A 4 2 1 Loading a realtime component ss c s ro em sa al De 4 22 Examining Mie HAL 6 a a a a a a ee a 1 2 3 Makine realite cod A AI 4 24 Changing parameters lt lt cos a a A A ao o a a A 4 2 5 Saving the HAL configuration esso sesers eses cesar 4 2 6 Restoring the HAL configuration a 4 3 Looking at the HAL with halmeter ooo e a a AA a a Be A a ee A Eh A e et 4 3 2 Using halmeter Las 240 SE A SE OMe Bi 4 4 A slightly more complex example
9. If we use UNITS 1 then we have defined our user units as millimeters If we use UNITS 0 03937007874016 then we have defined our user units as inches Using similar arithmetic we could set our units to most any value we wanted Some of the EMC2 people who run vehicles with the EMC2 set units to kilometers or miles After we have decided upon a value for the units for an axis we tell the EMC2 how may step pulses or encoder pulses it should send or read for each unit of distance to be traveled Once we have done this the EMC2 knows how to count units of distance However it is very important to understand that this counting of distance is different from the commanding of distance You can command distance in millimeters or inches without even thinking about the units that you defined There are G codes that allow you to switch easily between metric and imperial 1 7 2 Some things we may not want to change Within the EMC2 code are a few things that are not easily changed We call these defaults There are connections that have been made between the running components of the EMC2 that we can not easily change We ll see that there are displays and buttons and keyboard keys that are not easily shifted about We ll learn about and get used to these in the chapters ahead 1 7 3 Some things we will need to change The EMC2 is configured with files that are read at startup and used to override the compiled de faults No real controller will like
10. Modal commands are arranged in sets called modal groups and only one member of a modal group may be in force at any given time In general a modal group contains commands for which it is logically impossible for two members to be in effect at the same time like measure in inches vs measure in millimeters A machining center may be in many modes at the same time with one mode from each modal group being in effect The modal groups are shown in Table 8 2 For several modal groups when a machining center is ready to accept commands one member of the group must be in effect There are default settings for these modal groups When the machining center is turned on or otherwise re initialized the default values are automatically in effect Group 1 the first group on the table is a group of G codes for motion One of these is always in effect That one is called the current motion mode It is an error to put a G code from group 1 and a G code from group O on the same line if both of them use axis words If an axis word using G code from group 1 is implicitly in effect on a line by having been activated on an earlier line and a group O G code that uses axis words appears on the line the activity of the group 1 G code is suspended for that line The axis word using G codes from group O are G10 G28 G30 and G92 It is an error to include any unrelated words on a line with 0 flow control CHAPTER 8 LANGUAGE OVERVIEW Table 8 2 Moda
11. The interpretation is as if you were standing on the part walking behind the tool as it progresses across the part 15 4 1 Cutter Radius Compensation Detail The cutter radius compensation capabilities of the interpreter enable the programmer to specify that a cutter should travel to the right or left of an open or closed contour in the XY plane composed of arcs of circles and straight line segments The contour may be the outline of material not to be machined away or it may be a tool path to be followed by an exactly sized tool This figure shows two examples of the path of a tool cutting using cutter radius compensation so that it leaves a triangle of material remaining In both examples the shaded triangle represents material which should remain after cutting and the line outside the shaded triangle represents the path of the tip of a cutting tool Both paths will leave the shaded triangle uncut The one on the left with rounded corners is the path the inter preter will generate In the method on the right the one not used the tool does not stay in con tact with the shaded triangle at sharp corners This way NOT This way Z axis motion may take place while the contour is being followed in the XY plane Portions of the contour may be skipped by retracting the Z axis above the part following the contour to the next point at which machining should be done and re extending the Z axis These skip motions may be perfor
12. description try man halcmd or see the halcmd reference in section of this document The first halemd feature is the show command This command displays information about the current state of the HAL To show all installed components emc2 bin halcmd show comp Loaded HAL Components ID Type Name 02 User halcmd21345 01 RT siggen emc2 Since halcmd itself is a HAL component it will always show up in the list The list also shows the siggen component that we installed in the previous step The RT under Type indicates that siggen is a realtime component Next let s see what pins siggen makes available emc2 bin halcmd show pin Component Pins Owner Type Dir Value Name 02 float W 0 00000e 00 siggen 0 cosine 02 float W 0 00000e 00 siggen 0 sawtooth 02 float W 0 00000e 00 siggen 0 sine 02 float W 0 00000e 00 siggen 0 square 02 float W 0 00000e 00 siggen 0 triangle emc2 This command displays all of the pins in the HAL a complex system could have dozens or hundreds of pins But right now there are only five pins All five of these pins are floating point and all five carry data out of the siggen component Since we have not yet executed the code contained within the component all the pins have a value of zero The next step is to look at parameters emc2 bin halcmd show param Parameters Owner Type Dir Value Name 02 float W 1 00000e 00 siggen 0 amplitude 02 float W 1 00000e 00 sigg
13. in the center hub and connected with hubs on the ends of each spoke These outer hubs were connected to each other with longer spokes Pd spend hours dreaming of living in such a device walking from hub to hub around the outside as it slowly rotated producing near gravity in weightless space Supplies traveled through the spokes in elevators that transfered them to an from rockets docked at the center hub while they transfered their precious cargos The idea of one pin or component being the hub for many connections is also an easy concept within the HAL Examples two and four see section 4 connect the meter and scope to signals that are intended to go elsewhere Less easy is the notion of a hub for several incoming signals but that is also possible with proper use of functions within that hub component that handle those signals as they arrive from other components Another thought that comes forward from this toy is a mechanical representation of HAL threads A thread might look a bit like a centipede caterpillar or earwig A backbone of hubs HAL components strung together with rods HAL signals Each component takes in it own parameters and input pins and passes on output pins and parameters to the next component Signals travel along the backbone from end to end and are added to or modified by each component in turn Threads are all about timing and doing a set of tasks from end to end A mechanical representation is available with Tinkerto
14. length units To return to home position by way of the programmed position program G28 X Y Z A B C or use G30 All axis words are optional The path is made by a traverse move from the current position to the programmed position followed by a traverse move to the home position If no axis words are programmed the intermediate point is the current point so only one move is made CHAPTER 9 G CODES 87 9 10 G38 2 Straight Probe This code is currently unimplemented in EMC2 It is accepted but the behavior is undefined 9 11 G40 G41 G42 Cutter Radius Compensation To turn cutter radius compensation off program G40 It is OK to turn compensation off when it is already off Cutter radius compensation may be performed only if the XY plane is active To turn cutter radius compensation on left i e the cutter stays to the left of the programmed path when the tool radius is positive program G41 D To turn cutter radius compensation on right i e the cutter stays to the right of the programmed path when the tool radius is positive program G42 D The D word is optional if there is no D word the radius of the tool currently in the spindle will be used If used the D number should normally be the slot number of the tool in the spindle although this is not required It is OK for the D number to be zero a radius value of zero will be used It is an error if e the D number is not an integer is negative or is larger t
15. 3 2 Block Delete Switch If the block delete switch is on lines of RS274 NGC code which start with a slash the block delete character are not interpreted If the switch is off such lines are interpreted The Interpreter runs in two stages read and execute The driver tells the Interpreter when to perform each stage When the Interpreter reads a line starting with a slash it informs the driver I just read a line starting with a slash The driver checks the setting of the block delete switch If the switch is off it tells the Interpreter Execute that line If the switch is on the driver does not tell the Interpreter to execute the line Instead it tells the Interpreter to read another line with the result that the line starting with the slash is not executed 7 3 3 Optional Program Stop Switch The optional program stop switch works as follows If this switch is on and an input RS274 NGC code line contains an M1 code program execution is supposed to stop until the cycle start button is pushed EMC2 checks the optional stop switch when the OPTIONAL PROGRAM_STOP canonical function call is executed and either stops if the switch is on or not if the switch is off CHAPTER 7 MACHINING CENTER OVERVIEW 74 7 4 Tool File A tool file is required to use the Interpreter The file tells which tools are in which carousel slots and what the length and diameter of each tool are The format of a tool file is exemplified in Table
16. 5 3 Axis Position Displays aa c Rbk RR HERRERA ERED DEG Oe ee Es RESULTS CST gt ee cue a haw Oe ew ae a eS MESSAGES soe os oo we ew a e we a Ri a a BG aS Sie ane amp PS wee ee GO BUSOT COMIDA o Se Gee a See ES ee id a Oe a 6 6 1 6 6 2 6 6 3 6 6 4 Progam BAW oc c ccona A EERO A DG ee eee EMITAN TOLT TARG cui e a ee a O a GG Ae A e A aS OSet PASE a za cc A a a E A a AA 67 Keyboard Bindings so a AA A A PRG a Dk a 6 7 1 6 7 2 6 7 3 6 8 Misc COMIDO NEVA score a ER ERTS a OEE GRE OED GS Manual Mode senne doe haw eo Paw hae SP a bw wee See ee we be BDO Mode ee sa AD ee a Ae Qe as ca AE Bea a ee Sa Ae Ge ea a Bl we Ale Te we A 7 Machining Center Overview 7 1 Mechanital Components o e veas raars FARES area Fill 12 1 3 1 4 La 1 6 ader 1 8 7 1 9 NNNNNNN LCASE gl ea A Le a a a AE A wee eS Spindle ci a A A A ee AA A ea COOMA do bee o A A AA AS A AS A Ee EE BED Pallet Shuttle occiso AA a ee a Tool Carousel lt a A A PR AA A a A Ys Tool CHADBEF s ros s ios a a a a ee e el A A A AS hee e Fe d and Speed Override Switches os ce ee mrd omei s wti 7 1 10 Bl ck Delte SWB e a a a a ew ee Raw ok ee 7 1 11 Optional Program Stop Switch ss sa s scoe as EE A we we ee 7 2 Control and Data Components be a ee Teal 7 2 2 7 2 3 7 2 4 72D 7 2 6 Linear Axes ke oscsn asco asa a a a Controlled Point ooo danai nenin A PR Ew Coordinate Linear Mouom gt s ss sa a a a a A a A Feed Rate ER AR
17. 5 5 11 0 which simplifies to 1 0 0 5 which is 0 5 The logical operations and modulus are to be performed on any real numbers not just on integers The number zero is equivalent to logical false and any non zero number is equivalent to logical true CHAPTER 8 LANGUAGE OVERVIEW 80 8 3 4 Unary Operation Value A unary operation value is either ATAN followed by one expression divided by another expression for example ATAN 2 1 3 or any other unary operation name followed by an expression for example SIN 90 The unary operations are ABS absolute value ACOS arc cosine ASIN arc sine ATAN arc tangent COS cosine EXP e raised to the given power FIX round down FUP round up LN natural logarithm ROUND round to the nearest whole number SIN sine SORT square root and TAN tangent Arguments to unary operations which take angle measures COS SIN and TAN are in degrees Values returned by unary operations which return angle measures ACOS ASIN and ATAN are also in degrees The FIX operation rounds towards the left less positive or more negative on a number line so that FIX 2 8 2 and FIX 2 8 3 for example The FUP operation rounds towards the right more positive or less negative on a number line FUP 2 8 3 and FUP 2 8 2 for example 8 4 Parameter Setting A parameter setting is the following four items one after the other 1 a pound character 2 a
18. 8 3 and the Z position is 4 2 4 8 0 6 Old Z is 3 The first move is a traverse along the Z axis to 1 2 4 8 since old Z lt clear Z The first repeat consists of 3 moves l a traverse parallel to the XY plane to 5 7 4 8 2 a feed parallel to the Z axis to 5 7 4 2 3 a traverse parallel to the Z axis to 5 7 4 8 The second repeat consists of 3 moves The X position is reset to 9 5 4 and the Y position to 12 7 5 l a traverse parallel to the XY plane to 9 12 4 8 2 a feed parallel to the Z axis to 9 12 4 2 3 a traverse parallel to the Z axis to 9 12 4 8 The third repeat consists of 3 moves The X position is reset to 13 9 4 and the Y position to 17 12 5 l a traverse parallel to the XY plane to 13 17 4 8 2 a feed parallel to the Z axis to 13 17 4 2 3 a traverse parallel to the Z axis to 13 17 4 8 CHAPTER 9 G CODES 91 9 17 3 G82 Drilling Cycle with Dwell The G82 cycle is intended for drilling Program G82 X Y Z A B C R L P 1 Preliminary motion as described above Move the Z axis only at the current feed rate to the Z position Dwell for the P number of seconds Ae N Retract the Z axis at traverse rate to clear Z 9 17 4 G83 Peck Drilling The G83 cycle often called peck drilling is intended for deep drilling or milling with chip breaking The retracts in this cycle clear the hole of chips and cut off any long stringers which are common when drilling
19. C N0020 G41 Gl Y3 5 turn compensation on and make first entry move to point B N0030 G3 X2 Y2 5 Il make second entry move to point A See Figure 11 The figure shows the two entry moves but not the alignment move CHAPTER 15 TOOL FILE AND COMPENSATION 109 First pick a point A on the contour where it is convenient to attach an entry arc Specify an arc outside the contour which begins at a point B and ends at A tangent to the contour and going in the same direction as it is planned to go around the contour The radius of the arc should be larger than half the diameter given in the tool table Then extend a line tangent to the arc from B to some point C located so that the line BC is more than one radius long C 1 4 5 After the construction is finished the code is written in the reverse order from B 1 35 the construction Cutter radius com pensation is turned on after the align ment move and before the first entry move In the code above line N0010 is the alignment move line N0020 turns compensation on and makes the first entry move and line N0030 makes the second entry move A 2 2 5 Figure 11 Cutter Radius Compensation Entry Moves In this example the arc AB and the line BC are fairly large but they need not be For a tool path contour the radius of arc AB need only be slightly larger than the maximum possible deviation of the radius of the tool from the exact size Also for a tool path contour th
20. Distribution assuming it has been patched with a real time extension In addition to the raw code some binary distributions are available The latest packages have been created around the Ubuntu GNU Linux Distribution Ubuntu is one of the distributions that is aimed at novice Linux users and has been found to be very easy to use Along with that there are lots of places around the world that offer support for it Installing emc2 on it is trivial as you can see from Chapter 2 The EMC2 will not run under a normal Microsoft TM operating system The reason for this is that the EMC2 requires a real time environment for the proper operation of its motion planning and stepper pulse outputs Along with that it also benefits from the much needed stability and performance of the Linux OS 1 4 History of the Software The EMC2 code was started by the Intelligent Systems Division at the National Institute of Standards and Technology in the United States The quotation below taken from the NIST web presence some time back should lend some understanding of the essential reasons for the existence of this software and of the NIST involvement in it As part of our NIST collaboration with the OMAC User s Group we have written soft ware which implements real time control of equipment such as machine tools robots and coordinate measuring machines The goal of this software development is twofold first to provide complete software implementations of
21. EMC 15 3 Tool Length Offsets Tool length offsets are given as positive numbers in the tool table A tool length offset is programmed using G43 Hn where n is the desired table index It is expected that all entries in the tool table will be positive The H number is checked for being a non negative integer when it is read The interpreter behaves as follows 1 If G43 Hn is programmed A USE_TOOL_LENGTH_OFFSET length function call is made where length is the value of the tool length offset entry in the tool table whose index is n tool_length_offset is reset in the machine settings model and the value of current_z in the model is adjusted Note that n does not have to be the same as the slot number of the tool currently in the spindle 2 If G49 is programmed USE_TOOL_LENGTH_OFFSET 0 0 is called tool_length_offset is reset to 0 0 in the machine settings model and the value of current_z in the model is adjusted The effect of tool length compensation is illustrated in the screen shot below Notice that the length of the tool is subtracted from the z setting so that the tool tip appears at the programmed setting a You should note that the effect of tool length compensation is immediate when you view the z position as a relative coordinate but it does affect actual machine position until you program a z move Y BSS cleat Test tool length program X x z v z a Tool 1 is 1 inch long N01 Gl F15 X0 YO ZO NO2 G43 H1
22. NGC language and the canonical machining functions will still be usable as long as the lower levels of control know how to control the actual mechanisms to produce the same relative motion of tool and workpiece as would be produced by independent axes 2The requirement of parallelism is not used by either language so both languages are usable if any rotational axis is not parallel to any linear axis Rotational axis commands flow through both languages to lower levels of control without significant change in nature 69 CHAPTER 7 MACHINING CENTER OVERVIEW 70 7 1 3 Spindle A machining center has a spindle which holds one cutting tool probe or other item The spindle can rotate in either direction and it can be made to rotate at a constant rate which may be changed Except on machines where the spindle may be moved by moving a rotational axis the axis of the spindle is kept parallel to the Z axis and is coincident with the Z axis when X and Y are zero The spindle can be stopped in a fixed orientation or stopped without specifying orientation 7 1 4 Coolant A machining center has components to provide mist coolant and or flood coolant 7 1 5 Pallet Shuttle A machining center has a pallet shuttle system The system has two movable pallets on which workpieces can be fixtured Only one pallet at a time is in position for machining 7 1 6 Tool Carousel A machining center has a tool carousel with slots for tools fixed in tool holders
23. REO ADA ERAS ORR DEA RS OR i a COBISDL Socios tet eeaed beet a A 58 58 59 59 61 61 62 63 63 63 63 64 64 64 65 65 65 65 66 67 67 67 68 68 68 CONTENTS ER DI o A A E A RS E A AE a OS E A O PO UME e e e oP a A AE a A Pa A ee es be A TD COETCUE POSIAON lt gt lc e op ake ae we oa ae ae YO ae ay a ee Ba a TASE IGE boo eb panao AA AA EEG OSS Ee OS foe Hr de sk ae a ee ee a SE we ee De ee eee ee ae ed Teala TOOL Chong 6 ce A Se a ee a a a a a ee Sw we WO we A 7 2 18 Pallet Bile oos gk a we ee ae 7 2 14Feed and Speed Override Switches 7 2 JS PAI Comin Bede a cra a a ee a 7 3 Interpreter Interaction with Switches lt o ee ew a eee 7 3 1 Feed and Speed Override Switches cs ee ee Popes POCE Delete SWOR lt lt o ER Vow ke wet ae SE we Bone ee ee Bl A 1 3 3 Optional Program Stop Switch coo ooo tee bee ee eee eee ees TA TOOLS a a a a ee a Ol To Parameters sitos be hes os Es et RR aa RO A A le wo Dw a A 7 6 Coorditiete Systems ook ae daa a a ER Se EE wa AAA Language Overview Sl Format Lale eo gene lat wea ee a Ra RE eA ww g 52 LIE Number a a ee ee ee ae a A aa a SS WO a a AR A A RA AAA a e Sew ws adel a AAN Sd POLAIMICIES VAME o oo e a oe id Ee gl a 8 3 3 Expressions and Binary Operations 8 34 Unary Operation Valle s s ss segada aa egaa ars a Aa BA Parameter Sening orrea PR deka A A a SM 8 0 Comments and Messages occ a e E a e a ias mo Repeate
24. SYSTEM AND G92 OFFSETS 116 16 4 1 The G92 commands This set of commands include G92 This command when used with axis names sets values to offset variables G92 1 This command sets zero values to the g92 variables G92 2 This command suspends but does not zero out the g92 variables G92 3 This command applies offset values that have been suspended When the commands are used as described above they will work pretty much as you would expect A user must understand the correct ways that the g92 values work They are set based upon the location of each axis when the g92 command is invoked The NIST document is clear that To make the current point have the coordinates x0 yO and zO you would use g92 x0 yO z0 G92 does not work from absolute machine coordinates It works from current location G92 also works from current location as modified by any other offsets that are in effect when the g92 command is invoked While testing for differences between work offsets and actual offsets it was found that a g54 offset could cancel out a g92 and thus give the appearance that no offsets were in effect However the g92 was still in effect for all coordinates and did produce expected work offsets for the other coordinate systems It is likely that the absence of home switches and proper home procedures will result in very large errors in the application of g92 values if they exist in the var file Many EMC users do not have home switches in pla
25. TkEmc BackPlot yz 3D SETUP RESET CANCEL File View Settings Units Scripts ON MIST OFF SPINDLE OFF AUTO FLOOD OFF BRAKE ON Offset Work Offsets 0 0000 Y0 0000 20 0000 mm override limits relative machine actual commanded joint word continuous home Axis Speed E Feed Override MEN G1 G17 G40 G21 G90 G94 G54 G49 G99 G64 M2 M5 M9 M48 F225 51600 Program fhomefuve emc2inc_files 3D_Chips ngc Status idle Open Run Pause Resume Step Verify N6861Y56 0562 28 167 N6901Y56 1282 27 634 6911 G0210 Figure 1 5 The TkEmc Graphical Interface 1 6 1 Modes of Operation When an EMC2 is running there are three different major modes used for inputting commands These are Manual Auto and MDI Changing from one mode to another makes a big difference in the way that the EMC2 behaves There are specific things that can be done in one mode that can not be done in another An operator can home an axis in manual mode but not in auto or MDI modes An operator can cause the machine to execute a whole file full of G codes in the auto mode but not in manual or MDI In manual mode each command is entered separate In human terms a manual command might be turn on coolant or jog X at 25 inches per minute These are roughly equivalent to flipping a switch or turning the handwheel for an axis These commands are normally handled on one of the graphical interfaces by pressing a button with the mouse or
26. active the motion will differ from the above see Chapter If G53 is programmed on the same line the motion will also differ see Section 9 13 9 3 G2 G3 Arc at Feed Rate A circular or helical are is specified using either G2 clockwise arc or G3 counterclockwise arc The axis of the circle or helix must be parallel to the X Y or Z axis of the machine coordinate system The axis or equivalently the plane perpendicular to the axis is selected with G17 Z axis XY plane G18 Y axis XZ plane or G19 X axis YZ plane If the arc is circular it lies in a plane parallel to the selected plane If a line of RS274 NGC code makes an arc and includes rotational axis motion the rotational axes turn at a constant rate so that the rotational motion starts and finishes when the XYZ motion starts and finishes Lines of this sort are hardly ever programmed If cutter radius compensation is active the motion will differ from what is described here See Chapter Two formats are allowed for specifying an arc We will call these the center format and the radius format In both formats the G2 or G3 is optional if it is the current motion mode 9 3 1 Radius format arcs In the radius format the coordinates of the end point of the arc in the selected plane are specified along with the radius of the arc Program G2 X Y Z A B C R or use G3 instead of G2 R is the radius The axis words are all optional except that at least one of the
27. address these differences the EMC team came up with RTAPI which provides a consistent way for programs to talk to the RTOS If you are a programmer who wants to work on the internals of EMC you may want to study emc2 src rtapi rtapi h to understand the API But if you area normal person all you need to know about RTAPI is that it and the RTOS needs to be loaded into the memory of your computer before you do anything with HAL For this tutorial we are going to assume that you have successfully compiled the emc2 source tree In that case all you need to do is load the required RTOS and RTAPI modules into memory Just run the following command needs root privileges emc2 scripts realtime start With the realtime OS and RTAPI loaded we can move into the first example 4 2 A Simple Example 4 2 1 Loading a realtime component For the first example we will use a HAL component called siggen which is a simple signal generator A complete description of the siggen component can be found in section of this document It is a realtime component implemented as a Linux kernel module and located in the directory emc2 rt1ib To load siggen use the halcmd loadrt command emc2 bin halcmd loadrt siggen emc2 CHAPTER 4 HAL TUTORIAL 35 4 2 2 Examining the HAL Now that the module is loaded it is time to introduce halcmd the command line tool used to configure the HAL This tutorial will introduce some halcmd features for a more complete
28. all OMAC modules for the pur pose of validating application programming interfaces and second to provide a vehicle for the transfer of control technology to small and medium sized manufacturers via the NIST Manufacturing Extension Partnership The EMC2 software is based on the NIST Real time Control System RCS Methodology and is programmed using the NIST RCS Library The RCS Library eases the porting of controller code to a variety of Unix and Microsoft platforms providing a neutral application programming interface API to op erating system resources such as shared memory semaphores and timers The RCS Library also implements a communication model the Neutral Manufacturing Language which allows control processes to read and write C data structures throughout a single homogeneous environment or a heterogeneous networked environment The EMC2 soft ware is written in C and C and has been ported to the PC Linux Windows NT and Sun Solaris operating systems When running actual equipment a real time version of Linux is used to achieve the deterministic computation rates required 200 microseconds is typical The software can also be run entirely in simulation down to simulations of the machine motors This enables entire factories of EMC2 machines to be set up and run in a computer integrated manufacturing environment CHAPTER 1 THE ENHANCED MACHINE CONTROL 11 EMC has been installed on many machines both with servo motors and stepp
29. as the slot number of the tool in the spindle Tool Table Cutter radius compensation uses data from the machining center s tool table For each slot in the tool carrousel the tool table contains the diameter of the tool in that slot or the difference between the actual diameter of the tool in the slot and its nominal value The tool table is indexed by slot number How to put data into the table when using the stand alone interpreter is discussed in the tool table page Two Kinds of Contour The interpreter handles compensation for two types of contour e The contour given in the NC code is the edge of material that is not to be machined away We will call this type a material edge contour e The contour given in the NC code is the tool path that would be followed by a tool of exactly the correct radius We will call this type a tool path contour The interpreter does not have any setting that determines which type of contour is used but the description of the contour will differ for the same part geometry between the two types and the values for diameters in the tool table will be different for the two types Material Edge Contour When the contour is the edge of the material the outline of the edge is described in the NC program For a material edge contour the value for the diameter in the tool table is the actual value of the diameter of the tool The value in the table must be positive The NC code for a material edge con
30. axis at traverse rate to clear Z D a Pp WwW N Restart the spindle in the direction it was going The spindle must be turning before this cycle is used It is an error if e the spindle is not turning before this cycle is executed 9 17 8 G87 Back Boring This code is currently unimplemented in EMC2 It is accepted but the behavior is undefined 9 17 9 G88 Boring Spindle Stop Manual Out This code is currently unimplemented in EMC2 It is accepted but the behavior is undefined 9 17 10 G89 Boring Dwell Feed Out The G89 cycle is intended for boring This cycle uses a P number where P specifies the number of seconds to dwell program G89 X Y Z A B C R L P 1 Preliminary motion as described above 2 Move the Z axis only at the current feed rate to the Z position 3 Dwell for the P number of seconds 4 Retract the Z axis at the current feed rate to clear Z 9 17 11 G90 G99 Set Distance Mode Interpretation of RS274 NGC code can be in one of two distance modes absolute or incremental To go into absolute distance mode program G90 In absolute distance mode axis numbers X Y Z A B C usually represent positions in terms of the currently active coordinate system Any exceptions to that rule are described explicitly in this Section 9 17 To go into incremental distance mode program G91 In incremental distance mode axis numbers X Y Z A B C usually represent increments from the current va
31. button and the function that it activates is also bound to the pause button on most keyboards 6 4 5 ABORT The abort button stops any motion when it is pressed It also removes the motion command from the EMC No further motions are cued up after this button is pressed If you are in auto mode this button removes the rest of the program from the motion cue It also records the number of the line that was executing when it was pressed You can use this line number to restart the program after you have cleared up the reasons for pressing it 6 4 6 ESTOP The estop button is also a toggle but it works in three possible settings e When Mini starts up it will show a raised button with red background with black letters that say ESTOP PUSH This is the correct state of the machine when you want to run a program or jog an axis Estop is ready to work for you when it looks like this CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 64 e If you push the estop button while a motion is being executed you will see a recessed gray button that says ESTOPPED You will not be able to move an axis or do any work from the Mini gui when the estop button displays this way Pressing it with your mouse will return Mini to normal ready condition e A third view is possible here A recessed green button means that estop has been take off but the machine has not been turned on Normally this only happens when lt F1 gt estop has been pressed but l
32. check the accuracy of machined or molded parts DRO A Digital Read Out is a device attached to the slides of a machine tool or other device which has parts that move in a precise manner to indicate the current location of the tool with respect to some reference position Nearly all DRO s use linear quadrature encoders to pick up position information from the machine EDM EDM is a method of removing metal in hard or difficult to machine or tough metals or where rotating tools would not be able to produce the desired shape in a cost effective manner An excellent example is rectangular punch dies where sharp internal corners are desired Milling operations can not give sharp internal corners with finite diameter tools A wire EDM machine can make internal corners with a radius only slightly larger than the wire s radius A sinker EDM cam make corners with a radius only slightly larger than the radius on the corner of the convex EDM electrode EMC The Enhanced Machine Controller Initially a NIST A project EMC is able to run a wide range of motion devices EMCIO The module within EMCA that handles general purpose I O unrelated to the actual motion of the axes A couple examples are bridgeportio A and minimillio A EMCMOT The module within EMC A that handles the actual motion of the cutting tool It runs as a real time program and directly controls the motors Encoder Feed Relatively slow controlled motion of the tool used when making a
33. controller includes commands intended to activate physical capabilities the machine does not have For such a machine it would be useful to modify the Interpreter so it will reject input commands and will not produce output canonical function calls addressed to non existent equipment 7 1 Mechanical Components A machining center has many mechanical components that may be controlled or may affect the way in which control is exercised This section describes the subset of those components that interact with the Interpreter Mechanical components that do not interact directly with the Interpreter such as the jog buttons are not described here even if they affect control 7 1 1 Linear Axes A machining center has independent mechanisms for producing relative linear motion of the tool and workpiece in three mutually orthogonal directions These are the X Y and Z axes 7 1 2 Rotational axes Three additional independent mechanisms produce relative rotation of the workpiece and the tool around an axis These mechanisms often a rotary table on which the workpiece is mounted or a drum on which the spindle is mounted are called rotational axes and labelled A B and C The A axis is parallel to the X axis B is parallel to the Y axis and C parallel to the Z axis Each rotational mechanism may or may not have a mechanical limit on how far it can rotate Uf the motion of mechanical components is not independent as with hexapod machines the RS274
34. enabled or disabled 10 6 M100 to M199 User Defined Commands To invoke a user defined command program M P Q where P and Q are both optional The external program Mnnn in the directory DISPLAY PROGRAM_PREFIX is executed with the P and Q values as its two arguments Execution of the RS274NGC file pauses until the invoked program exits It is an error if e The specified User Defined Command does not exist Chapter 11 O Codes O codes provide for flow control in NC programs Each block has an associated number which is the number used after O Care must be taken to properly match the O numbers 11 1 Subroutines sub endsub return call Subroutines extend from a O sub to an O endsub The lines inside the subroutine the body are not executed in order instead they are executed each time the subroutine is called with O call 0100 sub subroutine to move to machine home GO X0 YO ZO 0100 endsub many intervening lines 0100 call Inside a subroutine O return can be executed This immediately returns to the calling code just as though O endsub was encountered O call takes optional arguments which are passed to the subroutine as 1 2 etc up to 30 On return from the subroutine the original values of those parameters will be restored Subroutine calls may not be nested They may only be called after they are defined They may be called from other functions and may call
35. every time the thread runs For now a quick example will help get the concept across We have a parport component named hal_parport That component defines one or more HAL pins for each physical pin The pins are described in that component s doc section their names how each pin relates to the physical pin are they inverted can you change polarity etc But that alone doesn t get the data from the HAL pins to the physical pins It takes code to do that and that is where functions come into the picture The parport component needs at least two functions One to read the physical input pins and update the HAL pins the other to take data from the HAL pins and write it to the physical output pins Both of these functions are part of the parport driver 3 3 HAL components Each HAL component is a piece of software with well defined inputs outputs and behaviour that can be installed and interconnected as needed This section lists available components and a brief description of what they do Complete details for each component are available later in this document 3 3 1 External programs with HAL hooks motion A realtime module that accepts NML motion commands and interacts with HAL iocontrol A user space module that accepts NML I O commands and interacts with HAL classicladder A PLC using HAL for all I O halui A user space program that interacts with HAL and sends NML commands note right now experimental it is intended to work as a full
36. figure 4 1 Note that you don t have to run halmeter in the background If you omit s it will start and behave exactly the same but you won t get your shell prompt back until you exit from halmeter X A HAL Meter MENTES Select Exit Figure 4 1 Halmeter at startup nothing selected 4 3 2 Using halmeter The meter in figure 4 1 isn t very useful because it isn t displaying anything To change that click on the Select button which will open the probe selection dialog figure 4 2 This dialog has three tabs The first tab displays all of the HAL pins in the system The second one displays all the signals and the third displays all the parameters We would like to look at the pin siggen 0 triangle first so click on it then click the OK button The probe selection dialog will close and the meter looks something like figure 4 3 You should see the value changing as siggen generates its triangle wave Halmeter refreshes its display about 5 times per second If you want to quickly look at a number of pins you can use the Accept button in the source selection dialog Click on Select to open the dialog again This time click on another pin like siggen 0 cosine and then click Accept When you click Accept the meter immediately begins to display the newly selected item but the dialog does not close Try displaying a parameter instead CHAPTER 4 HAL TUTORIAL 40 XA Select It
37. gone but the magic of building with interlocking pieces all the same size is something to watch Notice the following description of building a set of motion components in the HAL and how much like a wall of lego blocks it is The motion module exports a pin for each axis in cartesean space and another pin for each axis in joint space When it is loaded it automatically creates a jumper signal for each axis and automatically connects those signals from the joint pin to the cartesean pin So you automatically have trivkins as soon as you load the motion module trivkins trivial kinematics is the case where each motor moves a single axis at 90 degrees to the others The motion module is like a pair of legos in a line end to end Trivkins is just like a single block overlapping the two The in and out motion pins are plugged into each other by the block resting above But the parallel goes on If you need some other kinematics you then load a specific kins component This com ponent knows the names of the pins that the motion module uses for each axis both joint and cartesean When the module loads it again automatically creates signals and connects its own pins to the motion module s pins which will disconnect the jumpers It could also know the thread names used by the motion module and could automatically add it s own functions to those threads Trivkins is removed so that the motion blocks can be spread apart and by usin
38. holding down a key on the keyboard In auto mode a similar button or key press might be used to load or start the running of a whole program of G code that is stored in a file In the MDI mode the operator might type in a block of code and tell the machine to execute it by pressing the lt return gt or lt enter gt key on the keyboard Some motion control commands are available and will cause the same changes in motion in all modes These include ABORT ESTOP and FEEDRATE OVERRIDE Commands like these should be self explanatory 1 6 2 Information Display While an EMC2 is running each of the modules keeps up a dialog with each other and with the graphical display It is up to the display to select from that stream of information what the operator needs to see and to arrange it on the screen in a way that makes it easy for the operator to under stand Perhaps the most important display is the mode the EMC2 is running in You will want to CHAPTER 1 THE ENHANCED MACHINE CONTROL 17 His gi MISI C EEF 4 oPlAlte PIJ b _ 40 0RT MITO moanoFF ARARE ot aol u Fosti Actual Kalabve Monk Difael 2 0000 Work CTT Seta SOOO VOOR 2000000 2 3 9150 3 3 6875 O O 4 10 5600 Acs pemi increment Pore Mabon Feed Uvenwie Lopging e Ja contnuous tenants quu Y osea rot Logon u vaca y I GT HAR Ge GAANA Gnd Get GH Go Mi Me MH MA HIR HEIN rera AA Stats atema TEA D Th
39. home position This button will zero out any offsets and will home all axes right where they are Axis focus is important here Notice in figure 6 1 that in manual mode you see a line or groove around the X axis to highlight its position display This groove says that X is the active axis It will be the target for jog moves made with the plus and minus jog buttons You can change axis focus by clicking on any other axis display You can also change axis focus in manual mode if you press its name key on your keyboard Case is not important here Y or y will shift the focus to the Y axis A or a will shift the focus to the A axis To help you remember which axis will jog when you press the jog buttons the active axis name is displayed on them The EMC can jog move a particular axis as long as you hold the button down when it is set for continuous or it can jog for a preset distance when it is set for incremental You can also jog the active axis by pressing the plus or minus keys on the keyboard Again case is not important for keyboard jogs The two small buttons between the large jog buttons let you set which kind of jog you want When you are in incremental mode the distance buttons come alive You can set a distance by pressing it with the mouse You can toggle between distances by pressing i or I on the keyboard Incremental jog CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 62 has an interesting and often unexpected eff
40. in aluminum This cycle takes a Q number which represents a delta increment along the Z axis Program G83 X Y Z A B C R l Q 1 Preliminary motion as described above 2 Move the Z axis only at the current feed rate downward by delta or to the Z position whichever is less deep 3 Rapid back out to the clear_z 4 Rapid back down to the current hole bottom backed off a bit 5 Repeat steps 1 2 and 3 until the Z position is reached at step 1 6 Retract the Z axis at traverse rate to clear Z It is an error if e the Q number is negative or zero 9 17 5 G84 Right Hand Tapping This code is currently unimplemented in EMC2 It is accepted but the behavior is undefined 9 17 6 G85 Boring No Dwell Feed Out The G85 cycle is intended for boring or reaming but could be used for drilling or milling Program G85 X Y Z A B C R L 1 Preliminary motion as described above 2 Move the Z axis only at the current feed rate to the Z position 3 Retract the Z axis at the current feed rate to clear Z CHAPTER 9 G CODES 92 9 17 7 G86 Boring Spindle Stop Rapid Out The G86 cycle is intended for boring This cycle uses a P number for the number of seconds to dwell Program G86 X Y Z A B C R L P l Preliminary motion as described above Move the Z axis only at the current feed rate to the Z position Dwell for the P number of seconds Stop the spindle turning Retract the Z
41. interconnected and even replaced just like the external hardware It allows the system wiring diagram to show part of the internal controller rather than just a big black box And most importantly it allows the integrator to test and modify the controller using the same methods he would use on the rest of the hardware Terms like motors amps and encoders are familiar to most machine integrators When we talk about using extra flexible eight conductor shielded cable to connect an encoder to the servo input board in the computer the reader immediately understands what it is and is led to the question what kinds of connectors will I need to make up each end The same sort of thinking is essential for the HAL but the specific train of thought may take a bit to get on track Using HAL words may seem a bit strange at first but the concept of working from one connection to the next is the same This idea of extending the wiring diagram to the inside of the controller is what HAL is all about If you are comfortable with the idea of interconnecting hardware black boxes you will probably have little trouble using HAL to interconnect software black boxes 3 2 HAL Concepts This section is a glossary that defines key HAL terms but it is a bit different than a traditional glossary because these terms are not arranged in alphabetical order They are arranged by their relationship or flow in the HAL way of things CHAPTER 3 INTRODUCTION 27 Componen
42. is a valid line of code with two words G1 is a command meaning move in a straight line at the programmed feed rate and x3 provides an argument value the value of X should be 3 at the end of the move Most RS274 NGC commands start with either G or M for General and Miscellaneous The words for these commands are called G codes and M codes The RS274 NGC language has no indicator for the start of a program The Interpreter however deals with files A single program may be in a single file or a program may be spread across several files A file may demarcated with percents in the following way The first non blank line of a file may contain nothing but a percent sign possibly surrounded by white space and later in the file normally at the end of the file there may be a similar line Demarcating a file with percents is optional if the file has an M2 or M30 in it but is required if not An error will be signalled if a file has a percent line at the beginning but not at the end The useful contents of a file demarcated by percents stop after the second percent line Anything after that is ignored The RS274 NGC language has two commands M2 or M30 either of which ends a program A program may end before the end of a file Lines of a file that occur after the end of a program are not to be executed The interpreter does not even read them 8 1 Format of a line A permissible line of input RS274 NGC code c
43. leaves the compensation turned on Also note in line 15 that G17 is used to select the XY plane for circular interpolation I have used the radius form of arc center specification rather than the I J form EMC is very picky about the radius it computes from I J coordinates and they must match at the beginning and end of the move to within 10 11 internal units so you will have lots of problems with arbitrary arcs Usually if you do an arc of 90 degrees centered at 1 0 1 0 with a radius of 1 everything will go fine but if it has a radius that can not be expressed exactly in just a few significant digits or the arc is a strange number of degrees then there will be trouble with EMC The R word clears up all that mess and is a lot easier to work with anyway If the arc is more than 180 degrees R should be negative 15 5 Tool Compensation Sources This unit borrows heavily from the published works of Tom Kramer and Fred Proctor at NIST and the cutter compensation web page of Jon Elson Papers by Tom Kramer and Fred Proctor http www isd mel nist gov personnel kramer publications html http www isd mel nist gov personnel kramer pubs RS274NGC_22 pdf http www isd mel nist gov personnel kramer pubs RS274VGER_11 pdf Pages by Jon Elson http artsci wustl edu jmelson http 206 19 206 56 diacomp htm http 206 19 206 56 lencomp htm CHAPTER 15 TOOL FILE AND COMPENSATION 112 Chapter 16 Coordinate System and G92 Offsets
44. of simple components to make up a complex system The next example will use two components Before we can begin building this new example we want to start with a clean slate If you just finished one of the previous examples we need to remove the all components and reload the RTAPI and HAL libraries emc2 bin halcmd unloadrt all emc2 scripts realtime restart emc2 4 4 1 Installing the components Now we are going to load the step pulse generator component For a detailed description of this component refer to section For now we can skip the details and just run the following commands emc2 bin halcmd loadrt freqgen step_type 0 0 emc2 bin halcmd loadrt siggen emc2 bin halcmd loadrt threads namel fast fp1 0 period1 50000 name2 slow period2 1000 emc2 The first command loads two step generators both configured to generate stepping type 0 The second command loads our old friend siggen and the third one creates two threads a fast one with a period of 50 micro seconds and a slow one with a period of 1mS The fast thread doesn t support floating point functions As before we can use halcmd show to take a look at the HAL This time we have a lot more pins and parameters than before emc2 bin halcmd show pin Component Pins Owner Type Dir Value Name 03 float W 0 00000e 00 siggen 0 cosine 03 float W 0 00000e 00 siggen 0 sawtooth 03 float W 0 00000e 00 siggen 0 sine 03 float W 0 00000e 00 sig
45. positions for multiple parts A typical operation that uses fixture offsets would be to mill multiple copies of parts on islands in a piece similar to figure 16 1 The values for offsets are stored in the VAR file that is requested by the INI file during the startup of an EMC In our example below we ll use G55 The values for each axis for G55 are stored as variable numbers 113 CHAPTER 16 COORDINATE SYSTEM AND G92 OFFSETS 114 G53 G54 G55 XO YO X2 YO X4 YO Ci O X0 YO O X0 YO for for fixture 1 fixture 2 fixture 5 fixture 6 fixture 7 fixture 8 Figure 16 1 Work Offsets 5241 0 000000 5242 0 000000 5243 0 000000 5244 0 000000 5245 0 000000 5246 0 000000 In the VAR file scheme the first variable number stores the X offset the second the Y offset and so on for all six axes There are numbered sets like this for each of the fixture offsets Each of the graphical interfaces has a way to set values for these offsets You can also set these values by editing the VAR file itself and then issuing a reset so that the EMC reads the new values For our example let s directly edit the file so that G55 takes on the following values 5241 2 000000 5242 1 000000 5243 2 000000 5244 0 000000 5245 0 000000 5246 0 000000 You should read this as moving the zero positions of G55 to X 2 units Y 1 unit and Z 2 units away from the absolute zero position Once there are values assigned a call to G55 in a program bl
46. real value which evaluates to an integer between 1 and 5399 3 an equal sign and 4 a real value For example 3 15 is a parameter setting meaning set parameter 3 to 15 A parameter setting does not take effect until after all parameter values on the same line have been found For example if parameter 3 has been previously set to 15 and the line 3 6 G1 x 3 is interpreted a straight move to a point where x equals 15 will occur and the value of parameter 3 will be 6 8 5 Comments and Messages Printable characters and white space inside parentheses is a comment A left parenthesis always starts a comment The comment ends at the first right parenthesis found thereafter Once a left parenthesis is placed on a line a matching right parenthesis must appear before the end of the line Comments may not be nested it is an error if a left parenthesis is found after the start of a comment and before the end of the comment Here is an example of a line containing a comment G80 M5 stop motion Comments do not cause a machining center to do anything A comment contains a message if MSG appears after the left parenthesis and before any other printing characters Variants of MSG which include white space and lower case characters are allowed The rest of the characters before the right parenthesis are considered to be a message Messages should be displayed on the message display device Comments not containing m
47. select one of the nine systems by using G54 G55 G56 G57 G58 G59 G59 1 G59 2 or G59 3 see Section 9 14 It is not possible to select the absolute coordinate system directly You can offset the current coordinate system using G92 or G92 3 This offset will then apply to all nine program coordinate systems This offset may be cancelled with G92 1 or G92 2 See Section 9 18 You can make straight moves in the absolute machine coordinate system by using G53 with either GO or G1 See Section 9 13 Data for coordinate systems is stored in parameters During initialization the coordinate system is selected that is specified by parameter 5220 A value of 1 means the first coordinate system the one G54 activates a value of 2 means the second coordinate system the one G55 activates and so on It is an error for the value of parameter 5220 to be anything but a whole number between one and nine Chapter 8 Language Overview The RS274 NGC language is based on lines of code Each line also called a block may include commands to a machining center to do several different things Lines of code may be collected in a file to make a program A typical line of code consists of an optional line number at the beginning followed by one or more words A word consists of a letter followed by a number or something that evaluates to a number A word may either give a command or provide an argument to a command For example G1 x3
48. set to MODE_ABSOLUTE like G90 Feed rate mode is set to UNITS_PER_MINUTE like G94 Feed and speed overrides are set to ON like M48 Cutter compensation is turned off like G40 The spindle is stopped like M5 The current motion mode is set to G_1 like G1 Oo 0 XA OA Pp WO WN Coolant is turned off like M9 No more lines of code in an RS274 NGC file will be executed after the M2 or M30 command is executed Pressing cycle start will start the program back at the beginning of the file 10 2 M3 M4 M5 Spindle Control To start the spindle turning clockwise at the currently programmed speed program M3 To start the spindle turning counterclockwise at the currently programmed speed program M4 To stop the spindle from turning program M5 95 CHAPTER 10 M CODES 96 It is OK to use M3 or M4 if the spindle speed is set to zero If this is done or if the speed override switch is enabled and set to zero the spindle will not start turning If later the spindle speed is set above zero or the override switch is turned up the spindle will start turning It is OK to use M3 or M4 when the spindle is already turning or to use M5 when the spindle is already stopped 10 3 M6 Tool Change To change a tool in the spindle from the tool currently in the spindle to the tool most recently selected using a T word see Section 12 3 program M6 When the tool change is complete e The spindle will be stopped e The
49. siggen 0 update emc2 There is one more step needed before the siggen component starts generating signals When the HAL is first started the thread s are not actually running This is to allow you to completely configure the system before the realtime code starts Once you are happy with the configuration you can start the realtime code like this 2The codeaddr and arg fields were used in development and should probably be removed from the halemd listing CHAPTER 4 HAL TUTORIAL emc2 bin halcmd start emc2 Now the signal generator is running emc2 bin halcmd show pin Component Pins Owner 02 02 02 02 02 Type Dir float W float W float W float W float W De 6 8 sii 3 Value 61498e 01 89775e 01 27478e 01 00000e 00 719549e 01 emc2 bin halcmd show pin Component Pins Owner 02 02 02 02 02 emc2 Type Dir float W float W float W float W float W 8 1 Value 23063e 01 74322e 01 84649e 01 00000e 00 48645e 01 Name siggen siggen siggen siggen siggen Name siggen siggen siggen siggen siggen O OOO O ooooo Let s look at it s output pins cosine sawtooth sine square triangle cosine sawtooth sine square triangle 37 We did two show pin commands in quick succession and you can see that the outputs are no longer zero The sine cosine sawtooth and triangle outputs are ch
50. small circles in a diamond shape G10 L2 P1 x0 yO zO ensure that g54 is machine zero G10 L2 P2 x0 5 offsets g55 x value by 0 5 inch G10 L2 P3 x 0 5 offsets g56 x value by 0 5 inch G10 L2 P4 y0 5 offsets g57 y value by 0 5 inch G10 L2 P5 y 0 5 offsets g58 y value by 0 5 inch g54 gO x 1 yO zO center circle gl fl z 25 g3 x 1 yOi 1 jo gO zO g55 gO x 1 yO zO first offset circle gl fl z 25 g3 x 1 yOi 1 jO gO zO g56 gO x 1 yO zO second offset circle gl fl z 25 g3 x 1 yOi 1 jO gO zO g57 gO x 1 yO zO third offset circle gl fl z 25 gs x 1 yOi 1 jO gO zO g58 gO x 1 yO zO fourth offset circle gl fl z 25 g3 x 1 yOi 1 jO g54 g0 x0 yO zO m2 Now comes the time when we might apply a set of G92 offsets to this program You ll see that it is running in each case at zO If the mill were at the zero position a g92 z1 0000 issued at the head of the program would shift everything down an inch You might also shift the whole pattern around in the XY plane by adding some x and y offsets with g92 If you do this you should add a G92 1 command just before the m2 that ends the program If you do not other programs that you might run after this one will also use that g92 offset Furthermore it would save the g92 values when you shut down the EMC and they will be recalled when you start up again Appendix A Glossary of Common Terms Used in the EMC Documents GPLD Copyright 2003 LinuxCNC org A listin
51. this we use the Vertical controls in the box to the right of the screen These controls act on the currently selected channel When adjusting the gain notice that it covers a huge range unlike a real scope this one can display signals ranging from very tiny pico units to very large Tera units The position control moves the displayed trace up and down over the height of the screen only For larger adjustments the offset button should be used see the halscope reference in section for details 4 5 5 Triggering Using the Force button is a rather unsatisfying way to trigger the scope To set up real triggering click on the Source button at the bottom right It will pop up the Trigger Source dialog which is simply a list of all the probes that are currently connected Figure 4 8 Select a probe to use for triggering by clicking on it For this example we will use channel 3 the triangle wave XA Trigger Source x Select a channel to use for triggering ji Chan Source 2 Y_vel 3 siggen 1 triangle 4 siggen 1 square 5 pion 6 fren 7 pues 8 pies 9 Lua 10 11 1200 Cancel Figure 4 8 Trigger Source Dialog After setting the trigger source you can adjust the trigger level and trigger position using the sliders in the Trigger box along the right edge The level can be adjusted from the top to the bottom of the screen and is displayed below the s
52. tool that was selected by a T word on the same line or on any line after the previous tool change will be in the spindle The T number is an integer giving the changer slot of the tool not its id e If the selected tool was not in the spindle before the tool change the tool that was in the spindle if there was one will be in its changer slot e The coordinate axes will be stopped in the same absolute position they were in before the tool change but the spindle may be re oriented e No other changes will be made For example coolant will continue to flow during the tool change unless it has been turned off by an M9 The tool change may include axis motion while it is in progress It is OK but not useful to program a change to the tool already in the spindle It is OK if there is no tool in the selected slot in that case the spindle will be empty after the tool change If slot zero was last selected there will definitely be no tool in the spindle after a tool change 10 4 M7 M8 M9 Coolant Control To turn mist coolant on program M7 To turn flood coolant on program M8 To turn all coolant off program M9 It is always OK to use any of these commands regardless of what coolant is on or off 10 5 M48 M49 Override Control To enable the speed and feed override switches program M48 To disable both switches program M49 See Section 7 3 1 for more details It is OK to enable or disable the switches when they are already
53. two words for the axes in the selected plane must be used The R number is the radius A positive radius indicates that the arc turns through 180 degrees or less while a negative radius indicates a turn of 180 degrees to 359 999 degrees If the arc is helical the value of the end point of the arc on the coordinate axis parallel to the axis of the helix is also specified It is an error if e both of the axis words for the axes of the selected plane are omitted e the end point of the arc is the same as the current point It is not good practice to program radius format arcs that are nearly full circles or are semicircles or nearly semicircles because a small change in the location of the end point will produce a much larger change in the location of the center of the circle and hence the middle of the arc The magnification effect is large enough that rounding error in a number can produce out of tolerance cuts Nearly full circles are outrageously bad semicircles and nearly so are only very bad Other size arcs in the range tiny to 165 degrees or 195 to 345 degrees are OK Here is an example of a radius format command to mill an arc G17 G2 x 10 y 15 r 20 z 5 That means to make a clockwise as viewed from the positive Z axis circular or helical arc whose axis is parallel to the Z axis ending where X 10 Y 15 and Z 5 with a radius of 20 If the starting value of Z is 5 this is an arc of a circle parallel to the XY plane othe
54. up problems in G code programs or to find out why the machine stopped running As you work your way through this text you will be learning bit by bit how to setup and run a machine with your copy of the EMC2 software While you are learning about setting up and running a minimill here you will be thinking of other applications and other capabilities These are the topics of the other linuxcnc org handbooks 1 7 Thinking Like An Integrator The biggest task of a machine integrator is figuring out how to connect a PC running the EMC2 toa machine and configuring the software so that it runs the machine correctly Most of this is not the topic of this book but there are a few things that you will have to understand in order to make our little minimill work for us like we expect it to work 1 7 1 Units Units can be confusing A newbie recently asked Does it work in inches feet centimeters mil limeters or what There are several possible answers to this question but the best one is that it works in the units that you set it to work in At a machine level we set each axis units to some value using an INI variable that looks like this CHAPTER 1 THE ENHANCED MACHINE CONTROL 19 UNITS 1 or UNITS 0 03937007874016 Math folk will get a clue from these numbers because the long decimal number is the distance represented by one millimeter if we convert it into inches So you say the EMC2 uses millimeters internally
55. values which are not explicit numbers as just shown in the examples is rarely useful s If L is written in a prototype the will often be referred to as the L number Similarly the in H may be called the H number and so on for any other letter 9 1 GO Rapid Linear Motion For rapid linear motion program G0 X Y Z A B C where all the axis words are optional except that at least one must be used The GO is optional if the current motion mode is GO This will produce coordinated linear motion to the destination point at the current traverse rate or slower if the machine will not go that fast It is expected that cutting will not take place when a GO command is executing It is an error if e all axis words are omitted If cutter radius compensation is active the motion will differ from the above see Chapter If G53 is programmed on the same line the motion will also differ see Section 9 13 9 2 Gl Linear Motion at Feed Rate For linear motion at feed rate for cutting or not program G1 X Y Z A B C where all the axis words are optional except that at least one must be used The G1 is optional if the current motion mode is G1 This will produce coordinated linear motion to the destination point at the current feed rate or slower if the machine will not go that fast It is an error if 83 CHAPTER 9 G CODES 84 e all axis words are omitted If cutter radius compensation is
56. when the machine is in Auto mode These choices are made by the operator and entered using one of the Graphical User Interfaces available with the software G code is sent to the interpreter which compares the new block with what has already been sent to it The interpreter then figures out what needs to be done for the motion and input or output systems and sends blocks of canonical commands to the task and motion planning programs 1 6 Thinking Like a Machine Operator This book will not even pretend that it can teach you to run a mill or a lathe Becoming a machinist takes time and hard work An author once said We learn from experience if at all Broken tools gouged vices and scars are the evidence of lessons taught Good part finish close tolerances and careful work are the evidence of lessons learned No machine no computer program can take the place of human experience As you begin to work with the EMC2 program you will need to place yourself in the position of operator You need to think of yourself in the role of the one in charge of a machine It is a machine that is either waiting for your command or executing the command that you have just given it Throughout these pages we will give information that will help you become a good operator of the EMC2 mill You will need some information right up front here so that the following pages will make sense to you CHAPTER 1 THE ENHANCED MACHINE CONTROL 16 TREN
57. 0 9 17 2 G81 Drilling Cycle The G81 cycle is intended for drilling Program G81 X Y Z A B C R L 1 Preliminary motion as described above 2 Move the Z axis only at the current feed rate to the Z position 3 Retract the Z axis at traverse rate to clear Z Example 1 Suppose the current position is 1 2 3 and the XY plane has been selected and the following line of NC code is interpreted G90 G81 G98 X4 Y5 Z1 5 R2 8 This calls for absolute distance mode G90 and OLD_Z retract mode G98 and calls for the G81 drilling cycle to be performed once The X number and X position are 4 The Y number and Y position are 5 The Z number and Z position are 1 5 The R number and clear Z are 2 8 Old Zis 3 The following moves take place 1 a traverse parallel to the XY plane to 4 5 3 a traverse parallel to the Z axis to 4 5 2 8 a feed parallel to the Z axis to 4 5 1 5 Ae N a traverse parallel to the Z axis to 4 5 3 Example 2 Suppose the current position is 1 2 3 and the XY plane has been selected and the following line of NC code is interpreted G91 G81 G98 X4 Y5 Z 0 6 R1 8 L3 This calls for incremental distance mode G91 and OLD_Z retract mode G98 and calls for the G81 drilling cycle to be repeated three times The X number is 4 the Y number is 5 the Z number is 0 6 and the R number is 1 8 The initial X position is 5 1 4 the initial Y position is 7 2 5 the clear Z position is 4 8 1
58. 0 empty Figure 6 7 Mini Tool Display The Add Tools and Remove Tools buttons work on the bottom of the tool list so you will want to fill in tool information in decending order Once a new tool has been added you can use it ina program with the usual G code commands There is a 32 tool limit in the current EMC configuration files but you will run out of display space in Mini long before you get there Hint You can use menu gt view gt show popin full to see more tools if you need CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 67 6 6 4 Offset Page The offset page can be used to display and setup work offsets The coordinate system is selected along the left hand side of the window Once you have selected a coordinate system you can enter values or move an axis to a teach position You can also teach using an edgefinder by adding the COORDINATE SYSTEM SETUP Chick value to edit with keyboard Press anter to return to keyboard control of machine 054 ae oa XxX 9 000000 Teach 056 0 000000 Teach AO Z 0 000000 Teach v 058 v a59 Offest By Radins 0 000000 w 0591 Offset By Length 0 000000 y 059 2 Subtract add 9093 Zero AU G55 Write And Load File Figure 6 8 Mini Offset Display radius and length to the offset_by widgets When you do this you may need to add or subtract the radius depending upon which surface you choose to touch from This is selected with the add or subtract radiobuttons below the offs
59. 03 103 104 104 111 113 113 113 113 115 115 115 116 116 117 117 119 Part 1 Introduction amp installing EMC2 Chapter 1 The Enhanced Machine Control 1 1 Introduction This book is intended for people who want to use the Enhanced Machine Controller to run a mill lathe router or to control some other rather standard kind of machine Computer Numerical Control or CNC is the general term used to name this kind of computer application In order to get right into the essential task of operating it we have limited the amount of information about installation and setup We assume that the user will install from one of the standard ways of install covered in Chapter 2 Machine wiring and setup is limited to what we refer to as a mini or benchtop mill that is powered by stepper motors and amps that use a single parallel port If the user is interested in developing their own install using some other distribution of Linux or an other operating system or applying the EMC2 to a more complex machine they should study the Integrators Handbook where these topics are covered in greater detail 1 2 The Big CNC Picture The term CNC has taken on a lot of different meanings over the years In the early days it replaced the hands of a skilled machinist with motors that followed commands in much the same way that the machinist turned the handwheels From these early machines a language of machine tool control has grown This language i
60. 100 FT H i L NOS g This program is copyright of Rab Gordon Gary Drew and Paul Corner y 2 N10 It is released here under a GPL without warranty to do with as you may 22 N15 The part is cut from a 100x100x50mm block with the zero point at the i N20 center top of the block Cutter is a 10mm ball nose 32 N30 G21 N40G9 72 N50T1HM6 8 NG M8 33 N7OS1600H5 fon No tool Position Relative Actual Figure 1 2 The AXIS Graphical Interface The motion controller is written to be fairly generic Initialization files with the same syntax as Microsoft Windows INI files are used to configure parameters such as number and type of axes e g linear or rotary scale factors between feedback devices e g encoder counts and axis units e g millimeters servo gains servo and trajectory planning cycle times and other system parameters Complex kinematics for robots can be coded in C according to a prescribed function interface and linked in to replace the default 3 axis Cartesian machine kinematics routines The motion controllers that you will be using with your stepper motors will most likely be stepgen The ability and requirements of each of these will be described when we get to hardware and how to configure the EMC2 for your specific hardware 1 5 3 Discrete I O Controller EMCIO Discrete I O controllers are highly machine specific and are not customizable in general using the INI file technique used to configu
61. 16 COORDINATE SYSTEM AND G92 OFFSETS 117 16 4 3 G92 Cautions Sometimes the values of a G92 offset get stuck in the VAR file When this happens reset or a startup will cause them to become active again The variables are named 5211 0 000000 5212 0 000000 5213 0 000000 5214 0 000000 5215 0 000000 5216 0 000000 where 5211 is the X axis offset and so on If you are seeing unexpected positions as the result of a commanded move or even unexpected numbers in the position displays when you start up look at these variables in the VAR file and see if they contain values If they do set them to zeros and the problems should go away With these tests we can see that reset returns g92 to the condition that it had when the interpreter started up The reader should note that we have established that no write of these values occurs during a normal run so if no g92 was set at the startup none will be read in during a reset It may be that this is the heart of the problem that some have experienced with differences between the old and the new interpreter It may well be but I leave it to others to test that the old interpreter and task programs immediately wrote values to the var file and then found those values during a reset On the other hand if G92 values existed in the VAR file when the EMC started up Starting the EMC with g92 values in the var file is that it will apply the values to current location of each axis If this is home pos
62. 2 3 Y 0 6 JO 5 cut along arc at bottom left of tool path N0090 G1 X1 7 Y2 4 cut along hypotenuse of tool path 0100 G2 X2 Y2 5 10 3 J 0 4 cut along arc at top of tool path N0110 G40 turn compensation off This will result in the tool making an alignment move and two entry moves and then following a path slightly inside the path shown on the left in Figure 7 going clockwise around the triangle This path is to the right of the programmed path even though G41 was programmed because the diameter value is negative Programming Errors and Limitations The interpreter will issue the following messages involving cutter radius compensation E Cannot change axis offsets with cutter radius comp Cannot change units with cutter radius comp Cannot turn cutter radius comp on out of XY plane Cannot turn cutter radius comp on when already on Cannot use G28 or G30 with cutter radius comp Cannot use G53 with cutter radius comp Cannot use XZ plane with cutter radius comp Cannot use YZ plane with cutter radius comp oMN Da BR WD Concave corner with cutter radius comp Cutter gouging with cutter radius comp Eu E D word on line with no cutter comp on G41 or G42 command CHAPTER 15 TOOL FILE AND COMPENSATION 107 12 Tool radius index too big 13 Tool radius not less than arc radius with cutter radius comp 14 Two G codes used from same modal group For some of these messages additional explanation i
63. 2000 102 9 53 x0 y0 20 130 j 103 x1 yl start xy circle n104 17 02 x2 y2 regrt 0 5 105 x1 y 1 11 1 sqrt 0 51 106 0 2 1 add xy lettering 107 y1 75 108 29 Figure 6 4 Auto Mode Auto mode does not normally display the active or modal codes If the operator wishes to check these use menu Info gt Active_G Codes This will write all modal codes onto the message scratch pad If abort or estop is pressed during a run a set of buttons displays to the right of the text that allows the operator to shift the restart line forward or backwards If the restart line is not the last active line it will be highlighted as white letters on a blue background Caution a very slow feedrate and a finger poised over the pause button is advised during any program restart The real heart of CNC machine tool work is the auto mode Sherline s auto mode displays the typical functions that people have come to expect from the EMC Along the top are a set of buttons which control what is happening in auto mode Below them is the window that shows the part of the program currently being executed As the program runs the active line shows in white letters on a red background The first three buttons Open Run and Pause do about what you d expect Pause will stop the run right where it is The next button Resume will restart motion They are like feedhold if used this way Once Pause is pressed and motion has stopped Step will resum
64. 26
65. 7 1 Table 7 1 Sample Tool File AAA AA A pa 2 10 02 21 21 1737400 1 2 spot aril 32 s2 2476150 85mm da AA 228 360 0 10mmtap 60 60 0 o Targe chuck The file consists of any number of header lines followed by one blank line followed by any number of lines of data The header lines are ignored It is important that there be exactly one blank line with no spaces or tabs even before the data The header line shown in Table 7 1 describes the data columns so it is suggested but not required that such a line always be included in the header Each data line of the file contains the data for one tool Each line has five entries The first four entries are required The last entry a comment is optional It makes reading easier if the entries are arranged in columns as shown in the table but the only format requirement is that there be at least one space or tab after each of the first three entries on a line and a space tab or newline at the end of the fourth entry The meanings of the columns and the type of data to be put in each are as follows The Pocket column contains an unsigned integer which represents the pocket number slot num ber of the tool carousel slot in which the tool is placed The entries in this column must all be different The FMS column contains an unsigned integer which represents a code number for the tool The user may use any code for any tool as long as the codes are unsi
66. Backplot Tools and Offsets pop in each of these screens If more than one pop in is active button shown as red you can toggle between these pop ins by right clicking your mouse 6 4 Control Button Bar Below the menu line is a horizontal line of control buttons These are the primary control buttons for the interface Using these buttons you can change mode from MANUAL to AUTO to MDI Manual Data Input These buttons show a light green background whenever that mode is active You can also use the FEEDHOLD ABORT and ESTOP buttons to control a programmed move 6 4 1 MANUAL This button or pressing lt F3 gt sets the EMC to Manual mode and displays an abreviated set of buttons the operator can use to issue manual motion commands The labels of the jog buttons change to match the active axis Whenever Show_Mode_Full is active in in manual mode you will see spindle and lube control buttons as well as the motion buttons A keyboard lt i gt or lt I gt will switch from continuous jog to incremental jog Pressing that key again will toggle the increment size through the available sizes DEFAULT l Spesd 24 RAPID E 1 0000 0 1000 increment 0 0100 JOG Z JOGZ 0 0010 continnons 0 0001 Figure 6 3 Manual Mode Buttons A button has been added to designate the present position as the home position We felt that a machine of this type Sherline 5400 would be simpler to operate if it didn t use a machine
67. Between Motion CLF els ting Cycle oo eee tO et RRR RARE AA A a e A 9 17 3G82 Drilling Cycle with Dwell lt e s c saca aa sagres aad ee ee 9 17 4683 Peek Drilling 2 2 6b ke ms ss nanat riras ee A 9 17 5084 Right Hand Tapping cs ss sses nas PA ae be ER RAY a 9 17 6G85 Boring No Dwell Feed Out ee ee ee 9 17 7 G86 Boring Spindle Stop Rapid Out ee ee OU er Back DONDE psa gk othe ne Gok a HA A SR A AG ee ee a 9 17 9688 Boring Spindle Step Manual Out o com so 9 17 1089 Boring Dwell Peed QU oo aa ee a ad 217 670 G99 Set Distance Mode ono cada RRA A es 9 18G92 G92 1 G92 2 G92 3 Coordinate System Offsets 9 19693 G94 Set Peed Rate Mode so aa rak a e a a 9 20 G98 G99 Set Canned Cycle Return Level nc e esse 10M Codes 10 1 MO M1 M2 M30 M60 Program Stopping and Ending 10 2 M3 M4 MS Spindle Control cc cnc RE ee 103M0 Tool Change o o ae A A a o ea 10 4M7 M8 M9 Coolant Control ee 10 5M48 M49 Override Control aoso e ee 10 6M100 to M199 User Defined Commands ssaa e 11 O Codes 11 1 Subroutines sub endsub return call 2 ee ee ee 11 2 Looping do while endwhile break continue 1 SConditional if else endif co Ga da A AE ea a a a 12 Other Codes 12 1 F Set Peed Rate roscas ras a
68. Document means any work containing the Document or a portion of it either copied verbatim or with modifications and or translated into another language A Secondary Section is a named appendix or a front matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document s overall subject or to related matters and contains nothing that could fall directly within that overall subject For example if the Document is in part a textbook of mathematics a Secondary Section may not explain any mathematics The relationship could be a matter of historical connection with the subject or with related matters or of legal commercial philosophical ethical or political position regarding them The Invariant Sections are certain Secondary Sections whose titles are designated as being those of Invariant Sections in the notice that says that the Document is released under this License The Cover Texts are certain short passages of text that are listed as Front Cover Texts or Back Cover Texts in the notice that says that the Document is released under this License A Transparent copy of the Document means a machine readable copy represented in a format whose specification is available to the general public whose contents can be viewed and edited directly and straightforwardly with generic text editors or for images composed of pixels generic paint programs or for drawings som
69. Free Software Foundation If the Document does not specify a version number of this License you may choose any version ever published not as a draft by the Free Software Foundation ADDENDUM How to use this License for your documents To use this License in a document you have written include a copy of the License in the document and put the following copyright and license notices just after the title page Copyright c YEAR YOUR NAME Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 1 or any later version published by the Free Software Foundation with the Invariant Sections being LIST THEIR TITLES with the Front Cover Texts being LIST and with the Back Cover Texts being LIST A copy of the license is included in the section entitled GNU Free Documentation License If you have no Invariant Sections write with no Invariant Sections instead of saying which ones are invariant If you have no Front Cover Texts write no Front Cover Texts instead of Front Cover Texts being LIST likewise for Back Cover Texts If your document contains nontrivial examples of program code we recommend releasing these examples in parallel under your choice of free software license such as the GNU General Public License to permit their use in free software Index G code 14 G53 G54 G55 G56 G57 G58 G59 113 115 113 115 115 115 115 115 1
70. RIAL XA HAL Oscilliscope ICE Horizontal Zoom Pos Pa C E IDLE sf 2 s 4 s ef 7 a afrofrifre iafra is ie ore Selected Channel Run Mode 500 mSec 4047 samples Normal per div at 994 Hz C Single e Stop Vertical trieu fares i eure teens Gain Pos O Scale SEs Chan Off Trigger Normal C Auto Force Level Pos 4 Level Rising Source None Figure 4 5 Initial scope window 48 CHAPTER 4 HAL TUTORIAL 49 4 5 2 Hooking up the scope probes At this point Halscope is ready to use We have already selected a sample rate and record length so the next step is to decide what to look at This is equivalent to hooking virtual scope probes to the HAL Halscope has 16 channels but the number you can use at any one time depends on the record length more channels means shorter records since the memory available for the record is fixed at approximately 16 000 samples The channel buttons run across the bottom of the halscope screen Click button 1 and you will see the Select Channel Source dialog figure 4 6 This dialog is very similar to the one used by Halmeter We would like to look at the signals we defined earlier so we click on the Signals tab and the dialog displays all of the signals in the HAL only two for this example MAA Select Channel Source e selecta pin signal or
71. TOP button is pressed you ll get a message that says something about commanding motion when the EMC is not ready If an axis faults out for something like falling behind the message pad will show what happened If you want to remind an operator to change a tool for example you can add a line of code to your program that will display in the message box An example might be msg change to tool 3 and press resume This line of code included in a program will display change to tool 3 and press resume in the message box The word msg with comma included is the command to make this happen without msg the message wouldn t be displayed It will still show in the auto modes display of the program file To erase messages simply click the message button at the top of the pad or on the keyboard hold down the Alt key and press the m key 6 6 Right Column The right column is a general purpose place to display and work Here you can see the modal buttons and text entry or displays Here you can view a plot of the tool path that will be commanded by your program You can also write programs and control tools and offsets here The modal screens have been described above Each of the popin displays are described in detail below 6 6 1 Program Editor file adit osttimgs scripts z 20 n109 glyl25x14 y15x12 aiil y125x1 nii y175x14 2 mil4 y175x16 20 miie gliyl5x18 nii y1752 Figure 6 5 Mini Text Editor
72. The EMC2 Enhanced Machine Control User Handbook EMC The Enhanced Machine Controller www linuxcnc org The EMC Team 4th May 2006 This handbook is a work in progress If you are able to help with writing editing or graphic preparation please contact any member of the writing team or join and send an email to emc usersQlists sourceforge net Copyright c 2000 6 LinuxCNC org Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 1 or any later version published by the Free Software Foundation with no Invariant Sections no Front Cover Texts and one Back Cover Text This EMC Handbook is the product of several authors writing for linuxCNC org As you find it to be of value in your work we invite you to contribute to its revision and growth A copy of the license is included in the section entitled GNU Free Documentation License If you do not find the license you may order a copy from Free Software Foundation Inc 59 Temple Place Suite 330 Boston MA 02111 1307 Contents I 1 II 3 Introduction amp installing EMC2 The Enhanced Machine Control LiL DOMINICOS ooe o orete prama Hee Lhe DER hea hee DEG Me be ew de 12 We Biv CNC PRUNG co eee Hee ee Ow Ba ee ee Bae ew GS ee ee s 1 3 Computer Operating Systems es Gs eee rakanira ki Ge ee we ew 1 4 History of the SURESTE so asa e Oa REAR RA OR LS a Lar How the EMOCI VOTES o oo rar
73. User Interface using external knobs amp switches 3 3 2 Internal Components stepgen Software step pulse generator with position loop See section freqgen Software step pulse generator See section encoder Software based encoder counter See section pid Proportional Integral Derivative control loops See section siggen A sine cosine triangle square wave generator for testing See section supply a simple source for testing blocks assorted useful components mux demux or and integ ddt limit wcomp etc CHAPTER 3 INTRODUCTION 29 3 3 3 Hardware drivers hal_ax5214h A driver for the Axiom Measurement amp Control AX5241H digital I O board hal m5i20 Mesa Electronics 5i20 board hal_motenc Vital Systems MOTENC 100 board hal_parport PC parallel port See section hal_ppmc Pico Systems family of controllers PPMC USC and UPC hal _stg Servo To Go card version 1 amp 2 hal _ vti Vigilant Technologies PCI ENCDAC 4 controller 3 3 4 Utilities halemd Command line tool for configuration and tuning See section halgui GUI tool for configuration and tuning not implemented yet halmeter A handy multimeter for HAL signals See section halscope A full featured digital storage oscilloscope for HAL signals See section Each of these building blocks is described in detail in later chapters 3 4 Tinkertoys Erector Sets Legos and the HAL A first introduction to HAL concepts can be mind boggling Building anyth
74. Using The TKEMC Graphical Interface Chapter 6 Using The MINI Graphical Interface 6 1 Introduction Stepper Freqmod Minimill x 0 0000 Y 0 0000 tin ue MESSAGES Figure 6 1 The Mini Graphical Interface Mini was designed to be a full screen graphical interface It was first written for the Sherline CNC but is available for anyone to use copy and distribute under the terms of the GPL copyright Rather than popup new windows for each thing that an operator might want to do Mini allows you to display these within the regular screen Mini was written largely for the Sherline CNC mill Parts of this chapter are copied from the instructions that were written for that mill by Joe Martin and Ray Henry 1Much of this chapter quotes from a chapater of the Sherline CNC operators manual 58 CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 59 6 2 Screen layout 7 Sherline Steppermod Minimill E X Y 0 0000 Z 0 0000 Faad Overrida 100 Figure 6 2 Mini Display for a Running EMC The Mini screen is laid out in several sections See Figure6 1 These include a menu across the top a set of main control buttons just below the menu and two rather large columns of information that show the state of your machine and allow you to enter commands or programs When you compare figure6 1 with figure 6 2 you will see many differences In the second figure e each axis has been
75. X10 1972 Y3 432 COMP LEAD OUT 220 M02 Line 15 contains G41 D4 which means that the diameter of the tool described as tool 4 in the tool table will be used to offset the spindle by 1 2 the diameter which is of course the tool s radius Note that the line with the G41 command contains the endpoint of the move where the radius compensation is interpolated in What this means is that at the beginning of this move there is no compensation in effect and at the end the tool is offset by 100 of the selected tool radius Immediately after the G41 is D4 meaning that the offset is by the radius of tool number 4 in the tool table Note that tool DIAMETERS are entered in the tool table Jon s tool diameter is about 0 4890 But note that in line 110 where the G40 cancel cutter compensation command is that cutter compensation will be interpolated out in this move The way I have these set up the moves in lines 15 and 110 are almost exactly parallel to the X axis and the difference in Y coordinates is to line the tool up outside the portion of the program where cutter compensation is in force X Y PLOT Path of center of tool Direction of cut ll Onai ead 8 Offset lead in move eo a Actual part outline nd of da F cut Interior of part cot Some other things to note are that the program starts with a G40 to turn off any compensation that was in effect This saves a lot of hassle when the program stops due to a concavity error but
76. ZO X1 a ye Os NO3 G49 X0 Z0 ES on command N04 GO X2 943 ht DA NO5 Gl G43 H1 G4 P10 Z0 X3 20 1 NO6 G49 X2 Z0 NO7 GO XO Z Relative motion Machine motion The effect of this is that in most cases the machine will pick up the offset as a ramp during the next xyz move after the g43 word CHAPTER 15 TOOL FILE AND COMPENSATION 104 15 4 Cutter Radius Compensation Cutter Diameter Compensation also called Cutter Radius Compensation is something that was obviously added onto the RS 274D specification at the demand of users as it is VERY useful but the implementation was poorly thought out The purpose of this feature is to allow the programmer of the tool path program to virtualize the tool path so that the control can at run time determine the correct offset from the surface to be cut based on the tools available If you resharpen the side cutting edges of end mills then they will end up smaller than the standard diameters The problem is to describe to the control whether the tool is going to be cutting on the outside of an imaginary path or on the inside Since these paths are not necessarily closed paths although they can be it is essentially impossible for the control to know which side of the line it is supposed to offset to It was decided that there would only be two choices tool left of path and tool right of path This is to be interpreted as left or right when facing the direction of cutter motion
77. a a a ad a a a 12 29 Set Spindle Speed p s es rra a eraa OR a EKES a Be we BoT ECETIA A A AA A A ao ad i Ae S 13 Order of Execution 14 G Code Best Practices 14 1 Use an appropriate decimal precision s ee 2 ee 14 2Use consistent white space gt so aora sses mora na ee 14 5 Prefer Center format 40S sn eR EE eA a ea e e a 14 4 Put important modal settings at the top of the file 14 5Don t put too many things on one line IZ 6Dort 18 ine HUMBLE cosas eaa nua teyid ey SHEE OSS 87 87 88 88 88 88 89 90 91 91 91 91 92 92 92 92 92 93 93 94 95 95 95 96 96 96 96 97 97 97 98 99 99 99 99 100 CONTENTS 15 Tool File and Compensation 15 1Tool File 15 2 Tool Compensation 15 3Tool Length Offsets 15 4Cutter Radius Compensation 15 4 1 Cutter Radius Compensation Detail 15 5Tool Compensation Sources 16 Coordinate System and G92 Offsets 16 1 Introduction 16 2The Machine Position Command G53 16 3 Fixture Offsets G54 G59 3 16 3 1 Default coordinate system 16 3 2Setting coordinate system values within G code 16 4G92 Offsets 16 4 1The G92 commands 16 4 2Setting G92 values 16 4 3G92 Cautions 16 5Sample Program Using Offsets A Glossary of Common Terms Used in the EMC Documents A Legal Section A 1 GNU Free Documentation License Version 1 1 March 2000 A 1 1 GNU Free Documentation License Version 1 1 March 2000 102 102 1
78. a bad thing Real time Software that is intended to meet very strict timing deadlines Under Linux in order to meet these requirements it is necessary to install RTAI A or RTLINUX A and build the software to run in those special environments For this reason real time software runs in kernel space RTAI Real Time Application Interface see http www aero polimi it rtai http www aero polimi it rt one of two real time extensions for Linux that EMC can use to achieve real time A performance RTLINUX See http www rtlinux org http www rtlinux org one of two real time extensions for Linux that EMC can use to achieve real time A performance RS 274 NGC The formal name for the language used by EMC A part programs A Servo Motor Servo Loop Spindle On a mill or drill the spindle holds the cutting tool On a lathe the spindle holds the workpiece Stepper Motor A type of motor that turns in fixed steps By counting steps it is possible to deter mine how far the motor has turned If the load exceeds the torque capability of the motor it will skip one or more steps causing position errors TASK The module within EMC A that coordinates the overall execution and interprets the part program Tel Tk A scripting language and graphical widget toolkit with which EMC s most popular GUI s A were written World Coordinates This is the absolute frame of reference It gives coordinates in terms of a fixed reference frame that is attache
79. a discrete I O controller EMCIO a task executor which coordinates them EMCTASK and a collection of text based or graphical user interfaces An EMC2 capable of running a minimill must start some version of all four of these components in order to completely control it Each component is briefly described below In addition there is a layer called HAL Hardware Abstraction Layer which allows simple reconfiguration of EMC2 without the need of recompiling 1 5 1 Graphical User Interfaces A graphical interface is the part of the EMC2 that the machine tool operator interacts with The EMC2 comes with several types of user interfaces 2some parts of emc2 are released under LGPL to allow proprietary software to be linked together with emc2 GUIs hardware drivers etc CHAPTER 1 THE ENHANCED MACHINE CONTROL 12 Figure 1 1 Typical EMC2 Controlled Machine Power Supply Mater Supply Logic Supply Linux PC we Eme lla ho 1 i i 7 E BE CA ey Parallel A Pon Stepper stepper Drives Motors e an interactive command line program named emcpanel e a character based screen graphics program named keystick 1 3 e X Windows programs named xemc 1 6 and yemc e a Java based GUI emcgui e two Tcl Tk based GUIs named tkeme 1 5 and mini 1 4 e a modern GL based GUI written in python called AXIS 1 2 Tkemc and Mini are most commonly used operator interfaces They will run on Linux Mac and Microsoft Windows if the Tc
80. a single line of text for block entry and shows the currently active modal codes for the interpreter MDI mode allows you to enter single blocks and have the interpreter execute them as if they were part of a program kind of like a one line program You can execute circles arcs lines and such You can even test sets of program lines by entering one block waiting for that motion to end and then enter the next block Below the entry window there is a listing of all of the current modal codes This listing can be very handy I often forget to enter a g00 before I command a motion If nothing happens I look down there to see if g80 is in effect G80 stops any motion If it s there I remember to issue a block like g00 xO yO zO In MDI you are entering text from the keyboard so none of the main keys work for commands to the running machine F1 will Estop the control Since many of the keyboard keys are needed for entry most of the bindings that were available in auto mode are not available here 6 4 4 FEEDHOLD CONTINUE Feedhold is a toggle When the EMC is ready to handle or is handling a motion command this button shows the feedhold label on a red backgrouund If feedhold has been pressed then it will show the continue label Using it to pause motion has the advantage of being able to restart the program from where you stopped it Feedhold will toggle between zero speed and whatever feedrate override was active before it was pressed This
81. ably between machines G code programming is designed to work like a machinist might work The motion or turns of a handwheel are coded into blocks If a machinist wanted his mill to move an inch in the X direction at some feedrate he might slowly turn the handwheel five turns clockwise in 20 seconds The same machinist programming that same move for CNC might write the following block of code Gl F3 X1 000 Gl means that the machine is supposed to run at a programmed feedrate rather than at the fastest speed that it can GO The F3 means that it should travel at 3 inches a minute or 3 millimeters a minute if it is working in metric mode The X1 000 assumes that the machine started at zero and is supposed to go one inch in the positive direction You will read quite a bit more about G code in the programming chapters Figure 1 7 is a block diagram of how a personal computer running the EMC2 is used to control a machine with G code The actual G code can be sent using the MDI Machine Device Interface CHAPTER 1 THE ENHANCED MACHINE CONTROL 15 EMC HAL SIM Program View Settings Info Editor W Backplot 3 Tools MANUAL X 52 0000 Y 56 1280 Z 10 0000 Feed Overnde 120 Ela MESSAGES li zoom 1 U Refresh j Reset Open Run Pause Resume Step Verify idle N6891Y56 112 27 838 N6901 56 1282 27 634 N691160Z10 N6931M9 N6941M2 Figure 1 4 The Mini Graphical Interface mode or it can be sent as a file
82. ady been turned on it cannot be turned on again It must be turned off first then it can be turned on again It is not necessary to move the cutter between turning compensation off and back on but the move after turning it back on will be treated as a first move as described below It is not possible to change from one cutter radius index to another while compensation is on because of the combined effect of rules 4 and 11 It is also not possible to switch compensation from one side to another while compensation is on If the tool is already covering up the next XY destination point when cutter radius compensation is turned on the gouging message is given when the line of NC code which gives the point is reached In this situation the tool is already cutting into material it should not cut If a D word is programmed that is larger than the number of tool carrousel slots an error message is given In the current implementation the number of slots is 68 The error message two G Codes Used from Same Modal Group is a generic message used for many sets of G codes As applied to cutter radius compensation it means that more than one of G40 G41 and G42 appears on a line of NC code This is not allowed CHAPTER 15 TOOL FILE AND COMPENSATION First Move The algorithm used for the first move when the first move is a straight line is to draw a straight line from the desti nation point which is tangent to a cir cle whose center is at the cu
83. an appropriate decimal precision Use 3 digits after the decimal when milling in inches and 4 digits after the decimal when milling in millimeters In particular arc tolerance checks are made to 001 and 0001 depending on the active units 14 2 Use consistent white space G code is most legible when at least one space appears before words While it is permitted to insert whitespace in the middle of numbers there is no reason to do so 14 3 Prefer Center format arcs Center format arcs which use I J K instead of R behave more consistently than R format arcs particularly for included angles near 180 degrees 14 4 Put important modal settings at the top of the file When correct execution of your program depends on modal settings set them once and at the beginning of the file Perhaps the most critical modal setting is the distance value If you do not include G20 or G21 then different machines will mill the program at different scales Other settings such as the return mode in canned cycles may also be important 14 5 Don t put too many things on one line Ignore everything in Section 13 and instead write no line of code that is the slightest bit ambiguous Similarly don t use and set a parameter on the same line even though the semantics are well defined Exception Updating a variable to a new value such as 1 1 2 14 6 Don t use line numbers Line numbers offer no benefits When line numbers are reported in err
84. and Z are both omitted e or I and K are both omitted When the YZ plane is selected program G2 X Y Z A B C J K or use G3 instead of G2 The axis words are all optional except that at least one of Y and Z must be used J and K are the offsets from the current location in the Y and Z directions respectively of the center of the circle J and K are optional except that at least one of the two must be used It is an error if e Y and Z are both omitted e or J and K are both omitted Here is an example of a center format command to mill an arc G17 G2 x10 yl6 13 j4 z9 That means to make a clockwise as viewed from the positive z axis circular or helical arc whose axis is parallel to the Z axis ending where X 10 Y 16 and Z 9 with its center offset in the X direction by 3 units from the current X location and offset in the Y direction by 4 units from the current Y location If the current location has X 7 Y 7 at the outset the center will be at X 10 Y 11 If the starting value of Z is 9 this is a circular arc otherwise it is a helical arc The radius of this arc would be 5 In the center format the radius of the arc is not specified but it may be found easily as the distance from the center of the circle to either the current point or the end point of the arc 9 4 G33 Spindle Synchronized Motion For spindle synchronized motion code G33 X Y Z K where K gives the distance moved in XYZ for each revolution of the sp
85. and if so sets the outputs accordingly For smooth step pulses it should run as frequently as possible Because it needs to run so fast make_pulses is highly optimized and performs only a few calculations Unlike the others it does not need floating point math The last function freqgen update_fregq is responsible for doing scaling and some other calculations that need to be performed only when the frequency command changes What this means for our example is that we want to run siggen 0 update at a moderate rate to calculate the sine and cosine values Immediately after we run siggen 0 update we want to run freqgen update_freg to load the new values into the step pulse generator Finally we need to run freqgen make_pulses as fast as possible for smooth pulses Because we don t use position feedback we don t need to run freqgen capture_position at all We run functions by adding them to threads Each thread runs at a specific rate Let s see what threads we have available emc2 bin halcmd show thread Realtime Threads Period FP Name 1005720 YES slow 50286 NO fast emc2 oo SO O The two threads were created when we loaded threads The first one slow runs every millisecond and is capable of running floating point functions We will use it for siggen 0 update and freqgen update_freq The second thread is fast which runs every 50 microseconds and does not support floating point We will use it for freqgen
86. anded positions These can be changed using the Settings menu described below Tool_Info This adds a line immediately below the main position displays that shows which tool has been selected and the length of offset applied Offset_Info adds a line immediately below the tool info that shows what offsets have been applied This is a total distance for each axis from machine zero Show_Restart adds a block of buttons to the right of the program display in auto mode These allow the operator to restart a program after an abort or estop These will pop in whenever estop or abort is pressed but can be shows by the operator anytime auto mode is active by selecting this menu item Hide _Restart removes the block of buttons that control the restart of a program that has been aborted or estopped Show_Split_Right changes the nature of the right hand column so that it shows both mode and pop in information Show_Mode_Full changes the right hand column so that the mode buttons or displays fill the entire right side of the screen In manual mode running with mode full you will see spindle and lube control buttons as well as the motion buttons Show_Popin_Full changes the right hand column so that the popin fills the entire right side of the screen Settings These menu items allow the operator to control certain parameters during a run Actual Position sets the main position displays to actual machine based values Commanded Position sets the mai
87. anging constantly The square output is also working however it simply switches from 1 0 to 1 0 every cycle and it happened to be at 1 0 for both commands 4 2 4 Changing parameters The real power of HAL is that you can change things For example we can use the setp command to set the value of a parameter Let s change the amplitude of the signal generator from 1 0 to 5 0 emc2 bin halcmd setp siggen 0 amplitude 5 emc2 emc2 bin halcmd Parameters Owner Type Dir 02 float W 02 float W 02 float W emc2 bin halcmd Component Pins Owner Type Dir 02 float W 02 float W 02 float W 02 float W 02 float W emc2 bin halcmd Component Pins Owner Type Dir 02 float W Check the parameters and pins again show param Value 5 00000e 00 1 00000e 00 0 00000e 00 show pin Value 1 66602e 00 1 95935e 00 4 71428e 00 5 00000e 00 1 08130e 00 show pin Value 3 82623e 00 Name siggen 0 amplitude siggen 0 frequency siggen 0 offset Name siggen 0 cosine siggen 0 sawtooth siggen 0 sine siggen 0 square siggen 0 triangle Name siggen 0 cosine CHAPTER 4 HAL TUTORIAL 38 02 float W 1 11309e 00 siggen 0 sawtooth 02 float W 3 21869e 00 siggen 0 sine 02 float W 5 00000e 00 siggen 0 square 02 float W 2 77382e 00 siggen 0 triangle emc2 Note that the value of parameter siggen 0 amplitude has changed to 5 000 and that the pins now have larger values The square wave out
88. another module needing function X and not finding it HAL can follow the normal DLL model as well Although most components will simply export pins functions and parameters and then wait for the integrator or a saved file to interconnect them we can write modules that attempt to make connections when they are installed One specific place where this would work well is kinematics as illustrated in the Lego section 3 4 4 Chapter 4 HAL Tutorial 4 1 Before we start Configuration moves from theory to device HAL device that is For those who have had just a bit of computer programming this section is the Hello World of the HAL As noted above halemd can be used to create a working system It is a command line or text file tool for configuration and tuning The following examples illustrate its setup and operation 4 1 1 Notation Command line examples are presented in bold typewriter font Responses from the computer will be in typewriter font Text inside square brackets like this is optional Text inside angle brackets lt like this gt represents a field that can take on different values and the adjacent paragraph will explain the appropriate values Text items separated by a vertical bar means that one or the other but not both should be present All command line examples assume that you are in the emc2 directory and paths will be shown accordingly when needed 4 1 2 Root Privilges In the beginning days of HAL the
89. any particular order Switching the order of lines has no effect unless the same slot number is used on two or more lines which should not normally be done in which case the data for only the last such line will be used CHAPTER 7 MACHINING CENTER OVERVIEW 75 7 5 Parameters In the RS274 NGC language view a machining center maintains an array of 5400 numerical pa rameters Many of them have specific uses The parameter array persists over time even if the machining center is powered down EMC2 uses a parameter file to ensure persistence and gives the Interpreter the responsibility for maintaining the file The Interpreter reads the file when it starts up and writes the file when it exits Table 7 2 Parameters Used by the RS274NGC Interpreter G28 Home G30 Home 5261 5266 Coordinate System 3 The format of a parameter file is shown in Table 7 3 The file consists of any number of header lines followed by one blank line followed by any number of lines of data The Interpreter skips over the header lines It is important that there be exactly one blank line with no spaces or tabs even before the data The header line shown in Table 7 3 describes the data columns so it is suggested but not required that that line always be included in the header The Interpreter reads only the first two columns of the table The third column Comment is not read by the Interpreter Each line of the file contains the index number of a
90. apped linear axes are used regardless of whether or not there is a mechanical limit on rotation Clockwise or counterclockwise is from the point of view of the workpiece If the workpiece is fastened to a turntable which turns on a rotational axis a counterclockwise turn from the point of view of the workpiece is accomplished by turning the turntable in a direction that for most common machine configurations looks clockwise from the point of view of someone standing next to the machine 7 2 3 Controlled Point The controlled point is the point whose position and rate of motion are controlled When the tool length offset is zero the default value this is a point on the spindle axis often called the gauge point that is some fixed distance beyond the end of the spindle usually near the end of a tool holder that fits into the spindle The location of the controlled point can be moved out along the spindle axis by specifying some positive amount for the tool length offset This amount is normally the length of the cutting tool in use so that the controlled point is at the end of the cutting tool 7 2 4 Coordinate Linear Motion To drive a tool along a specified path a machining center must often coordinate the motion of several axes We use the term coordinated linear motion to describe the situation in which nominally each axis moves at constant speed and all axes move from their starting positions to their end positions at the same ti
91. as GREE Pee ete eens ye tees 15 1 Graphical User Meraces fe ee a Se Cae ee eae ee ae Bee 1 5 2 Motion Controller EMCMOT e 0 4 6 626 a ss ED ee Ee EA es 1 5 3 Discrete I O Controller EMCIO 20 0 0 0 ee eee ee eee 1 54 Task Executor EMCTASK escocesas aE RAD Re RG aes 1 6 Thinking Like a Machine Operator coc rea Oe OER ee ee ee 1 6 1 Modes Of Operation lt c o ocs eac ae RRR RR RE EK EA ee 10 2 Information Display oa cuisine pd a i 1 7 Thinking Like An Integrator lt css ew OR aR OR a a e ds EAEL OS a Bd o e a A aw l 1 7 2 Some things we may not want to change o o 00000000 1 7 3 Some things we will need to Change o Installing the EMC2 software dl TOUS cosa eka a ee e A eG wed wo 22 EMC Download Page o ee ed ee ee ee A ee ee a els 2 3 EMC2 install script the easy way to install 2 4 Manual installing using apt commands 0 2 0 eee eee Configuring EMC2 Introduction Sid WISIS HAL o eh a Ok A Re ee ee Sw a we a 3 1 1 HAL is based on traditional system design techniques 311 1 Part Selection 6445 24 6S Ro ser ars ER REARS Ow G a 3 1 1 2 Interconnection Design 50 004 0e da SLi Implementation copada A A BS a LL TORTS a gw ee A ew ee dea DLL DUMMA osos Cae AA ARA RES RE GOES RG HR eG mee FAL CODCEPIS iron ebb eS OSS eR EERE EEG EE EEEE EE Ham SD ES 10 10 11 11 12 13 14 15 16 16 18 18 19 19
92. ce on their machines For them home should be found by moving each axis to a location and issuing the home command When each axis is in a known location the home command will recalculate how the g92 values are applied and will produce consistent results Without a home sequence the values are applied to the position of the machine when the EMC begins to run 16 4 2 Setting G92 values There are at least two ways to set G92 values right mouse click on position displays of tkemc will popup a window into which you can type a value e the g92 command Both of these work from the current location of the axis to which the offset is to be applied Issuing g92 x y za b c does in fact set values to the g92 variables such that each axis takes on the value associated with it s name These values are assigned to the current position of the machine axis These results satisfy paragraphs one and two of the NIST document G92 commands work from current axis location and add and subtract correctly to give the current axis position the value assigned by the g92 command The effects work even though previous offsets are in So if the X axis is currently showing 2 0000 as its position a G92 xO will set an offset of 2 0000 so that the current location of X becomes zero A G92 X2 will set an offset of 0 0000 and the displayed position will not change A G92 X5 0000 will set an offset of 3 0000 so that the current displayed position becomes 5 0000 CHAPTER
93. chanical system This is typically done in software in the controller This can correct the final resting place of the part in motion but fails to solve problems related to direction changes while in motion think circular interpolation and motion that is caused when external forces think cutting tool pulling on the work piece are the source of the motion Ball Screw A type of lead screw that uses small hardened steel balls between the nut A and screw to reduce friction Ball screws have very low friction and backlash A but are usually quite expensive Ball Nut A special nut designed for use with a ball screw It contains an internal passage to re circulate the balls from one end of the screw to the other bridgeportio An I O task A designed to work with a Bridgeport milling machine having a variable speed spindle A coolant and lube pumps and some other stuff CNC Computer Numerical Control The general term used to refer to computer control of machin ery Instead of a human operator turning cranks to move a cutting tool CNC uses a computer and motors to move the tool based on a part program A 119 APPENDIX A GLOSSARY OF COMMON TERMS USED IN THE EMC DOCUMENTS 120 Coordinate Measuring Machine A Coordinate Measuring Machine is used to make many accurate measurements on parts These machines can be used to create CAD data for parts where no drawings can be found when a hand made prototype needs to be digitized for moldmaking or to
94. cut Feedrate The speed at which a motion occurs In manual mode jog speed can be set from the graphical interface In auto or mdi mode feedrate is commanded using a f word F10 would mean ten units per minute Feedback Feedrate Override A manual operator controlled change in the rate at which the tool moves while cutting Often used to allow the operator to adjust for tools that are a little dull or anything else that requires the feed rate to be tweaked G Code The generic term used to refer to the most common part programming language There are several dialects of G code EMC uses RS274 NGC A GUI Graphical User Interface General A type of interface that allows communications between a computer and human in most cases via the manipulation of icons and other elements widgets on a computer screen EMC An application that presents a graphical screen to the machine operator allowing manip ulation of machine and the corresponding controlling program Home A specific location in the machine s work envelope that is used to make sure the computer and the actual machine both agree on the tool position ini file A text file that contains most of the information that configures EMC A for a particular machine Joint_Coordinates These specify the angles between the individual joints of the machine Kine matics APPENDIX A GLOSSARY OF COMMON TERMS USED IN THE EMC DOCUMENTS 121 Jog Manually moving an axis of a machine Jog
95. d EMOS a a Bee we OR a pee O da ds os eee hape OEE ESA OG SRR EERE EHS O ee Ee eS 8 8 Commands and Machine Modes oee aw we ae ek ee ee Ee BS Modal GLOSARIO Se oe es G Codes 9 1 G0 Rapid Linear Motion oo ocio a eA A A AAA a a dk A 9 2 Gl Linear Motion at Feed Rate ee 93 G2 Ga Arcal Feed Bale cio ss isis a a a 985 1 Radius format arcs sana a ee ws ew a 13 2 Cemer ormat PGB ee ek ee we ee Re ee a a ee we 9 4 G33 Spindle Synchronized Motion 1 0 ee ee ee ee ee DD GE Dwell oe cand rake m eee REESE EEA SESE GE REESE EE Se RSE 96 GIO Set Coordinate Systemi Data o ss o ss soona as a ee we eee 97 GIL G18 G19 Plane Selection nk ke RR ARR ARG YS 4 8 621 621 Lens Umts 000 caca A A A ek 9 9 G25 G30 Return do Home i s 6s coronarse a a a a a POG SS 22 SAIS PROG o e odoro oca a baa d A A a a Sel 9 11 G40 G41 G42 Cutter Radius Compensation 72 72 72 72 72 72 72 73 73 73 73 73 73 74 75 75 77 77 78 78 78 79 79 80 80 80 80 81 81 81 CONTENTS 8 12643 G49 Tool Length Ofisete oo e i ek ke A ee POR AG ey wo 9 13G53 Move in absolute coordinates lt ee ee 9 14G54 te 659 37 Select Coordinate Systemi gt o o oie we ls 9 15G61 G61 1 G64 Set Path Control Mode 26 serere rareste sere e 9 16 G60 Cancel Modal Motion sos e ecr sm ers e e 9 17 Gel te G89 Canned Cycles gt o oos sares a daa iae d au a a A we A 9 17 1 Preliminary and In
96. d only once per pass A perfect example is a single rung ladder with a NC contact in series with a coil The contact and coil belong to the same relay If this were a conventional relay as soon as the coil is energized the contacts begin to open and de energize it That means the contacts close again etc etc The relay becomes a buzzer With a PLC if the coil is OFF and the contact is closed when the PLC begins to evaluate the rung then when it finishes that pass the coil is ON The fact that turning on the coil opens the contact feeding it is ignored until the next pass On the next pass the PLC sees that the contact is open and de energizes the coil So the relay still switches rapidly between on and off but at a rate determined by how often the PLC evaluates the rung In HAL the function is the code that evaluates the rung s In fact a HAL aware realtime version of ClassicLadder would export a function to do exactly that Meanwhile a thread is the thing that runs the function at specific time intervals Just like you can choose to have a PLC evaluate all its rungs every 10mS or every second you can define HAL threads with different periods What distinguishes one thread from another is _not_ what the thread does that is determined by which functions are connected to it The real distinction is simply how often a thread runs In EMC we might have a 15uS thread a 1mS thread and a 10mS thread These would be created based on Pe
97. d to some point generally the base of the machine tool Appendix A Legal Section Handbook Copyright Terms Copyright c 2000 LinuxCNC org Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 1 or any later version published by the Free Software Foundation with no Invariant Sections no Front Cover Texts and one Back Cover Text This EMC Handbook is the product of several authors writing for linuxCNC org As you find it to be of value in your work we invite you to contribute to its revision and growth A copy of the license is included in the section entitled GNU Free Documentation License If you do not find the license you may order a copy from Free Software Foundation Inc 59 Temple Place Suite 330 Boston MA 02111 1307 A 1 GNU Free Documentation License Version 1 1 March 2000 Copyright C 2000 Free Software Foundation Inc 59 Temple Place Suite 330 Boston MA 02111 1307 USA Everyone is permitted to copy and distribute verbatim copies of this license document but changing it is not allowed A 1 1 GNU Free Documentation License Version 1 1 March 2000 Copyright C 2000 Free Software Foundation Inc 59 Temple Place Suite 330 Boston MA 02111 1307 USA Everyone is permitted to copy and distribute verbatim copies of this license document but changing it is not allowed O PREAMBLE The purpose of this License is to make a manual textb
98. dius Compensation is Performed The complete set of canonical functions includes functions which turn cutter radius on and off so that cutter radius compensation can be performed in the controller executing the canonical CHAPTER 15 TOOL FILE AND COMPENSATION 110 functions In the interpreter however these commands are not used Compensation is done by the interpreter and reflected in the output commands which continue to direct the motion of the center of the cutter tip This simplifies the job of the motion controller while making the job of the interpreter a little harder Algorithms for Cutter Radius Compensation The interpreter allows the entry and exit moves to be arcs The behavior for the intermediate moves is the same except that some situations treated as errors in the interpreter are not treated as errors in other machine controls Data for Cutter Radius Compensation The interpreter machine model keeps three data items for cutter radius compensation the setting itself right left or off program_x and program _y The last two represent the X and Y positions which are given in the NC code while compensation is on When compensation is off these both are set to a very small number 10 20 whose symbolic value in a define is unknown The interpreter machine model uses the data items current_x and current_y to represent the position of the center of the tool tip in the currently active coordinate system at all times
99. e or slower if the machine will not go that fast If GO is active the speed of motion is the current traverse rate or slower if the machine will not go that fast It is an error if CHAPTER 9 G CODES 88 e G53 is used without GO or G1 being active e or G53 is used while cutter radius compensation is on See Section 7 6 for an overview of coordinate systems 9 14 G54 to G59 3 Select Coordinate System To select coordinate system 1 program G54 and similarly for other coordinate systems The system number G code pairs are 1 G54 2 G55 3 G56 4 G57 5 G58 6 G59 7 G59 1 8 G59 2 and 9 G59 3 It is an error if e one of these G codes is used while cutter radius compensation is on See Section 7 6 for an overview of coordinate systems 9 15 G61 G61 1 G64 Set Path Control Mode Program G61 to put the machining center into exact path mode G61 1 for exact stop mode or G64 P for continuous mode with optional tolerance It is OK to program for the mode that is already active See Section 7 2 15 for a discussion of these modes 9 16 G80 Cancel Modal Motion Program G80 to ensure no axis motion will occur It is an error if e Axis words are programmed when G80 is active unless a modal group O G code is programmed which uses axis words 9 17 G81 to G89 Canned Cycles The canned cycles G81 through G89 have been implemented as described in this section Two examples are given with the description o
100. e allowed but not required A number written with initial or trailing zeros will have the same value when it is read as if the extra zeros were not there Numbers used for specific purposes in RS274 NGC are often restricted to some finite set of values or some to some range of values In many uses decimal numbers must be close to integers this includes the values of indexes for parameters and carousel slot numbers for example M codes and G codes multiplied by ten A decimal number which is supposed be close to an integer is considered close enough if it is within 0 0001 of an integer 8 3 2 Parameter Value A parameter value is the pound character followed by a real value The real value must evaluate to an integer between 1 and 5399 The integer is a parameter number and the value of the parameter value is whatever number is stored in the numbered parameter The character takes precedence over other operations so that for example 1 2 means the number found by adding 2 to the value of parameter 1 not the value found in parameter 3 Of course 1 2 does mean the value found in parameter 3 The character may be repeated for example 2 means the value of the parameter whose index is the integer value of parameter 2 8 3 3 Expressions and Binary Operations An expression is a set of characters starting with a left bracket and ending with a balancing right bracket In between the brackets are numbers parameter values
101. e motion and continue it to the end of the current block Press Step again to get the motion of the next block Press Resume and the interpreter goes back to reading ahead and running the program The combination of Pause and Step work a lot like single block mode on many controllers The difference is that Pause does not let motion continue to the end of the current block Feedrate Override can be very handy as you approach a first cut Move in quickly at 100 percent throttle back to 10 and toggle between Feedhold and CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 63 10 using the pause button When you are satisfied that you ve got it right hit the zero to the right of nine and go The Verify button runs the interpreter through the code without initiating any motion If Verify finds a problem it will stop the read near the problem block and put up some sort of message Most of the time you will be able to figure out the problem with your program by reading the message and looking in the program window at the highlighted line Some of the messages are not very helpful Sometimes you will need to read a line or two ahead of the highlight to see the problem Occasionally the message will refer to something well ahead of the highlight line This often happens if you forget to end your program with an acceptable code like m2 m30 or m60 6 4 3 MDI The MDI button or lt F5 gt sets the Manual Data Input mode This mode displays
102. e side chosen for compensation should be the one to use if the tool is oversized As mentioned earlier if the tool is undersized the interpreter will switch sides Simple Method If the contour is a material edge contour and there is a convex corner somewhere on the contour a simpler method of making an entry is available See Figure 12 First pick a convex corner D Decide which way you want to go along the contour from D In our example we are keeping the tool to the left of the contour and going next towards F Extend the line FD if the next part of the contour is an arc extend the tangent to arc FD from D to divide the area outside the contour near D into two regions Make sure the center of the tool is currently in the region on the same side of the extended line as the material inside the contour near D If not move the tool into that region In the example point E represents the current location of the center of the tool Since it is on the same side of line DF as the shaded triangle no additional move is needed Now write a line of NC code that turns compensation on and moves to point D N0010 G41 G1 X2 Y2 turn E compensation on and make entry move This method will also work at a concave corner on a tool path contour if the ac tual tool is oversized but it will fail with a tool path contour if the tool is under sized Figure 12 Simpler Cutter Radius Compensation Entry Move Other Items Where Cutter Ra
103. e widely available drawing editor and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters A copy made in an otherwise Transparent file format whose markup has been designed to thwart or discourage subsequent modification by readers is not Transparent A copy that is not Transparent is called Opaque Examples of suitable formats for Transparent copies include plain ASCII without markup Texinfo input format FIX input format SGML or XML using a publicly available DTD and standard conforming simple HTML designed for human modification Opaque formats include PostScript PDF proprietary formats that can be read and edited only by proprietary word processors SGML or XML for which the DTD and or processing tools are not generally available and the machine generated HTML produced by some word processors for output purposes only The Title Page means for a printed book the title page itself plus such following pages as are needed to hold legibly the material this License requires to appear in the title page For works in formats which do not have any title page as such Title Page means the text near the most prominent appearance of the work s title preceding the beginning of the body of the text 2 VERBATIM COPYING You may copy and distribute the Document in any medium either commercially or noncommercially provided that this License the copyright not
104. each for the screwdriver screw parts to be bolted together and nut Perseverence along with father s eventual boredom got me to where I had built every project in the booklet Soon I was lusting after the bigger sets that were also printed on that paper Working with those regular sized pieces opened up a world of construction for me and soon I moved well beyond the illustrated projects Hal components are not all the same size and shape but they allow for grouping into larger units that will do useful work In this sense they are like the parts of an Erector set Some components are long and thin They essentially connect high level commands to specific physical pins Other components are more like the rectangular platforms upon which whole machines could be built An integrator will quickly get beyond the brief examples and begin to bolt together components in ways that are unique to them 3 4 3 Tinkertoys Wooden Tinker toys had a more humane feel that the cold steel of Erector Sets The heart of construction with Tinker Toys was a round connector with eight holes equally spaced around the circumference It also had a hole in the center that was perpendicular to all the holes around the hub Hubs were connected with rods of several different lengths Builders would make large wheels by using these rods as spokes sticking out from the center hub My favorite project was a rotating space station Short spokes radiated from all the holes
105. ect If you press the jog button while a jog is in progress it will add the distance to the position it was at when the second jog command was issued Two one inch jog presses in close succession will not get you two inches of movement You have to wait until the first one is complete before jogging again Jog speed is displayed above the slider It can be set using the slider by clicking in the slider s open slot on the side you want it to move toward or by clicking on the Default or Rapid buttons This setting only affects the jog move while in manual mode Once a jog move is initiated jog speed has no effect on the jog As an example of this say you set jog mode to incremental and the increment to 1 inch Once you press the Jog button it will travel that inch at the rate at which it started 6 4 2 AUTO When the Auto button is pressed or lt F4 gt on the keyboard the EMC is changed into that mode a set of the traditional auto operation buttons is displayed and a small text window opens to show a part program During run the active line will be displayed as white lettering on a red background In the auto mode many of the keyboard keys are bound to controls For example the numbers above the querty keys are bound to feedrate override The O sets 100 9 sets 90 and such Other keys work much the same as they do with the tkemc graphical interface This is a test plot nc program to ba ran on backplot Author Ray Henry 10 Fab
106. ed The RS274 NGC language has one command that enables both switches and one command that disables both see Section 10 4 See Section 7 3 1 for further details 7 2 15 Path Control Mode The machining center may be put into any one of three path control modes 1 exact stop mode 2 exact path mode or 3 continuous mode with optional tolerance In exact stop mode the machine stops briefly at the end of each programmed move In exact path mode the machine follows the programmed path as exactly as possible slowing or stopping if necessary at sharp corners of the path In continuous mode sharp corners of the path may be rounded slightly so that the feed rate may be kept up but by no more than the tolerance if specified See Section 9 15 7 3 Interpreter Interaction with Switches The Interpreter interacts with three switches This section describes the interactions in more detail In no case does the Interpreter know what the setting of any of these switches is 7 3 1 Feed and Speed Override Switches The Interpreter will interpret RS274 NGC commands which enable M48 or disable M49 the feed and speed override switches It is useful to be able to override these switches for some machining operations The idea is that optimal settings have been included in the program and the operator should not change them EMC2 reacts to the setting of the speed or feed override switches on the control panel when these switches are enabled 7
107. em to Probe Pins Signals Parameters siggen 1 sine siggen 1 square siggen 1 triangle OK Accept Cancel Figure 4 2 Halmeter source selection dialog X A HAL Meter lx 3 71923e 00 siggen 1 triangle Select Figure 4 3 Halmeter displaying the value of a pin CHAPTER 4 HAL TUTORIAL 41 of a pin Click on the Parameters tab then select a parameter and click Accept again You can very quickly move the meter probes from one item to the next with a couple of clicks To shut down halmeter just click the exit button If you want to look at more than one pin signal or parameter at a time you can just start more halmeters The halmeter window was intentionally made very small so you could have a lot of them on the screen at once 3Halmeter is due for a rewrite The rewrite will do a number of things to make it nicer Scientific notation will go away it is a pain to read Some form of ranging including autoranging will be added to allow it to display a wide range of numbers without using scientific notation An analog bar graph display will also be added to give a quick indication of trends When the rewrite is done these screenshots and the accompanying text will be revised to match the new version CHAPTER 4 HAL TUTORIAL 42 4 4 Aslightly more complex example Up till now we have only loaded one HAL component But the whole idea behind the HAL is to allow you to load and connect a number
108. en 0 frequency 02 float W 0 00000e 00 siggen 0 offset 02 s32 R 0 siggen 0 update time 02 32 RW 0 siggen 0 update tmax emc2 The show param command shows all the parameters in the HAL Right now each parameter has the default value it was given when the component was loaded Note the column labeled Dir The parameters labeled w are writeable ones that are never changed by the component itself instead they are meant to be changed by the user to control the component We will see how to do this later Parameters labeled R are read only parameters They can be changed only by the component Finally parameter labeled RW are read write parameters That means that thay are changed by the component but can also be changed by the user Note the parameters lThe number after halemd in the component list is the process ID It is possible to run more than one copy of halemd at the same time in different windows for example so the PID is added to the end of the name to make it unique CHAPTER 4 HAL TUTORIAL 36 siggen 0 update time and siggen 0 update tmax are for debugging purposes and won t be covered in this section Most realtime components export one or more functions to actually run the realtime code they contain Let s see what function s siggen exported emc2 bin halcmd show funct Exported Functions Owner CodeAddr Arg FP Users Name 02 C48E31C4 C48D2054 YES 0 siggen 0 update emc2 The siggen component exported a single f
109. er motors Here is a sampling of the earliest applications e 3 axis Bridgeport knee mill at Shaver Engineering The machine uses DC brush servo motors and encoders for motion control and OPTO 22 compatible I O interfaced to the PC parallel port for digital I O to the spindle coolant lube and e stop systems e 3 axis desktop milling machine used for prototype development The machine uses DC brush servo motors and encoders Spindle control is accomplished using the 4th motion control axis The machine cuts wax parts e 4 axis Kearney amp Trecker horizontal machining center at General Motors Powertrain in Pontiac MI This machine ran a precursor to the full software EMC2 which used a hardware motion control board After these early tests Jon Elson found the Shaver Engineering notes and replaced a refrigerator sized Allen Bradley 7300 control on his Bridgeport with the EMC running on a Red Hat 5 2 distri bution of Linux He was so pleased with the result that he advertised the software on several news groups He continues to use that installation and has produced several boards that are supported by the software From these early applications news of the software spread around the world It is now used to con trol many different kinds of machines More recently the Sherline company http www sherline com has released their first CNC mill It uses a standard release of the EMC The source code files that make up the controller are kept
110. essages need not be displayed there 8 6 Repeated Items A line may have any number of G words but two G words from the same modal group see Section 8 9 may not appear on the same line A line may have zero to four M words Two M words from the same modal group may not appear on the same line For all other legal letters a line may have only one word beginning with that letter If a parameter setting of the same parameter is repeated on a line 3 15 3 6 for example only the last setting will take effect It is silly but not illegal to set the same parameter twice on the same line If more than one comment appears on a line only the last one will be used each of the other comments will be read and its format will be checked but it will be ignored thereafter It is expected that putting more than one comment on a line will be very rare CHAPTER 8 LANGUAGE OVERVIEW 81 8 7 Item order The three types of item whose order may vary on a line as given at the beginning of this section are word parameter setting and comment Imagine that these three types of item are divided into three groups by type The first group the words may be reordered in any way without changing the meaning of the line If the second group the parameter settings is reordered there will be no change in the meaning of the line unless the same parameter is set more than once In this case only the last setting of the parameter will take effect Fo
111. et windows The zero all for the active coordinate system button will remove any offsets that you have showing but they are not set to zero in the variable file until you press the write and load file button as well This write and load file button is the one to use when you have set all of the axis values that you want for a coordinate system 6 7 Keyboard Bindings A number of the bindings used with tkemc have been preserved with mini A few of the bindings have been changed to extend that set or to ease the operation of a machine using this interface Some keys operate the same regradless of the mode Others change with the mode that EMC is operating in 6 7 1 Common Keys Pause Toggle feedhold Escape abort motion F1 toggle estop estop reset state F2 toggle machine off machine on state F3 manual mode F4 auto mode F5 MDI mode F6 reset interpreter The following only work for machines using auxiliary I O F7 toggle mist on mist off F8 toggle flood on flood off CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 68 F9 toggle spindle forward off F10 toggle spindle reverse off F11 decrease spindle speed F12 increase spindle speed 6 7 2 Manual Mode 1 9 O set feed override to 10 90 O is 100 set feed override to O or feedhold select X axis o y select Y axis select Z axis N a select A axis b select B axis c select C axis Left Right Arrow jog X axis Up Down Arrow jog Y axis Page Up Down jog Z axis
112. f G81 below All canned cycles are performed with respect to the currently selected plane Any of the three planes XY YZ ZX may be selected Throughout this section most of the descriptions assume the XY plane has been selected The behavior is always analogous if the YZ or XZ plane is selected Rotational axis words are allowed in canned cycles but it is better to omit them If rotational axis words are used the numbers must be the same as the current position numbers so that the rotational axes do not move All canned cycles use X Y R and Z numbers in the NC code These numbers are used to determine X Y R and Z positions The R usually meaning retract position is along the axis perpendicular to the currently selected plane Z axis for XY plane X axis for YZ plane Y axis for XZ plane Some canned cycles use additional arguments For canned cycles we will call a number sticky if when the same cycle is used on several lines of code in a row the number must be used the first time but is optional on the rest of the lines Sticky numbers keep their value on the rest of the lines if they are not explicitly programmed to be different The R number is always sticky In incremental distance mode when the XY plane is selected X Y and R numbers are treated as increments to the current position and Z as an increment from the Z axis position before the CHAPTER 9 G CODES 89 move involving Z takes place when the YZ or XZ pla
113. fied versions provided that you include in the combination all of the Invariant Sections of all of the original documents unmodified and list them all as Invariant Sections of your combined work in its license notice The combined work need only contain one copy of this License and multiple identical Invariant Sections may be replaced with a single copy If there are multiple Invariant Sections with the same name but different contents make the title of each such section unique by adding at the end of it in parentheses the name of the original author or publisher of that section if known or else a unique number Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work In the combination you must combine any sections entitled History in the various original documents forming one section entitled History likewise combine any sections entitled Acknowledgements and any sections entitled Dedications You must delete all sections entitled Endorsements 6 COLLECTIONS OF DOCUMENTS APPENDIX A LEGAL SECTION 125 You may make a collection consisting of the Document and other documents released under this License and replace the individual copies of this License in the various documents with a single copy that is included in the collection provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects You may ex
114. form you can use the zoom slider at the top of the screen to expand the waveforms horizontally and the position slider to determine which part of the zoomed waveform is visible However sometimes simply expanding the waveforms isn t enough and you need to increase the sampling rate For example we would like to look at the actual step pulses that are being generated in our example Since the step pulses may be only 50uS long sampling at 1KHz isn t fast enough To change the sample rate click on the button that displays the record length and sample rate to bring up the Select Sample Rate dialog figure For this example we will click on the 50uS thread fast which gives us a sample rate of about 20KHz Now instead of displaying about 4 seconds worth of data one record is 4000 samples at 20KHz or about 0 20 seconds XA Select Sample Rate x Select a thread name and multiplier then click OK or Click Quit to exit HALSCOPE Thread stepgen thread Sample Period 50 3 uSec Sample Rate 19 9 KHz Thread Period E siggenihread 1 01 mSec stepgen thread 50 3 uSec Multiplier 1 Record Length C 16191 samples 1 channel C 8095 samples 2 channels 4047 samples 4 channels C 2023 samples 8 channels C 1011 samples 16 channels OK Quit Figure 4 10 Sample Rate Dialog CHAPTER 4 HAL TUTORIAL 54 4 5 7 More Channels Now let s look at the step pulses Halscope has 16 channels b
115. g of terms and what they mean Some terms have a general meaning and several additional meanings for users installers and developers Acme Screw A type of lead screw A that uses an acme thread form Acme threads have somewhat lower friction and wear than simple triangular threads but ball screws A are lower yet Most manual machine tools use acme lead screws Axis One of the computer control movable parts of the machine For a typical vertical mill the table is the X axis the saddle is the Y axis and the quill or knee is the Z axis Additional linear axes parallel to X Y and Z are called U V and W respectively Angular axes like rotary tables are referred to as A B and C Backlash The amount of play or lost motion that occurs when direction is reversed in a lead screw A or other mechanical motion driving system It can result from nuts that are loose on leadscrews slippage in belts cable slack wind up in rotary couplings and other places where the mechanical system is not tight Backlash will result in inaccurate motion or in the case of motion caused by external forces think cutting tool pulling on the work piece the result can be broken cutting tools This can happen because of the sudden increase in chip load on the cutter as the work piece is pulled across the backlash distance by the cutting tool Backlash Compensation Any technique that attempts to reduce the effect of backlash without actually removing it from the me
116. g other blocks a different bridge is built between input and output pins In Lego terms trivkins might be a gray block and xxkins might be a yellow block So the net result is that 24 HAL signals and two HAL functions are configured with no action needed by the integrator other than loading the module 24 signals are from 6 axis 2 because we have joint and cartesean 2 because we have forward and inverse kinematics Two functions because we have forward and inverse Because these HAL signals exist they can be metered or scoped or whatever for testing But because both modules know their names and know how to automatically connect them the integrator doesn t have to know or care This kind of automatic HAL configuration is possible because all kinematics modules plug in the same way 3 5 Timing Issues In HAL Threads is going to take a major intellectual push because unlike the physical wiring models between black boxes that we have said that HAL is based upon simply connecting two pins with a hal signal falls far short of the action of the physical case True relay logic consists of relays connected together and when a contact opens or closes current flows or stops immediately Other coils may change state etc and it all just happens But in CHAPTER 3 INTRODUCTION 32 PLC style ladder logic it doesn t work that way Usually in a single pass through the ladder each rung is evaluated in the order in which it appears an
117. gen 0 square 03 float W 0 00000e 00 siggen 0 triangle 02 s32 W 0 fregqgen 0 counts 02 bit W FALSE freqgen 0 dir 02 float W 0 00000e 00 freqgen 0 position 02 bit W FALSE freqgen 0 step 02 float R 0 00000e 00 freqgen 0 velocity 02 s32 W 0 fregqgen 1 counts 02 bit W FALSE freqgen 1 dir 02 float W 0 00000e 00 freqgen 1 position 02 bit W FALSE freqgen 1 step 02 float R 0 00000e 00 freqgen 1 velocity emc2 bin halcmd show param Parameters Owner Type Dir Value Name 03 float W 1 00000e 00 siggen 0 amplitude 03 float W 1 00000e 00 siggen 0 frequency 03 float W 0 00000e 00 siggen 0 offset CHAPTER 4 HAL TUTORIAL 43 02 u8 W 1 01 freqgen 0 dirhold 02 u8 W 1 01 freqgen 0 dirsetup 02 float R 0 00000e 00 freqgen 0 frequency 02 float W 0 00000e 00 freqgen 0 maxaccel 02 float W 1 00000e 15 freqgen 0 maxfreq 02 float W 1 00000e 00 freqgen 0 position scale 02 s32 R 0 freqgen 0 rawcounts 02 u8 W 1 01 freqgen 0 steplen 02 u8 W 1 01 freqgen 0 stepspace 02 float W 1 00000e 00 freqgen 0 velocity scale 02 u8 W 1 01 freqgen 1 dirhold 02 u8 W 1 01 freqgen 1 dirsetup 02 float R 0 00000e 00 freqgen 1 frequency 02 float W 0 00000e 00 freqgen 1 maxaccel 02 float W 1 00000e 15 freqgen 1 maxfreq 02 float W 1 00000e 00 freqgen 1 position scale 02 s32 R 0 freqgen 1 rawcounts 02 u8 W 1 01 freqgen 1 steplen 02 u8 W 1 01 freqgen 1 stepspace 02 float W 1 00000e 00 freqgen 1 velocity
118. ging either moves the axis a fixed amount for each key press or moves the axis at a constant speed as long as you hold down the key kernel space Kinematics The position relationship between world coordinates A and joint coordinates A of a machine There are two types of kinematics Forward kinematics is used to calculate world co ordinates from joint coordinates Inverse kinematics is used for exactly opposite purpose Note that kinematics does not take into account the forces moments etc on the machine It is for positioning only Lead screw An screw that is rotated by a motor to move a table or other part of a machine Lead screws are usually either ball screws A or acme screws A although conventional triangular threaded screws may be used where accuracy and long life are not as important as low cost MDI Manual Data Input This is a mode of operation where the controller executes single lines of G code A as they are typed by the operator minimillio An I O task A designed to work with small table top mills NIST National Institute of Standards and Technology An agency of the Department of Commerce in the United States Offsets Part Program A description of a part in a language that the controller can understand For EMC that language is RS 274 NGC commonly known as G code A Rapid Fast possibly less precise motion of the tool commonly used to move between cuts If the tool meets the material during a rapid it is probably
119. gned integers The TLO column contains a real number which represents the tool length offset This number will be used if tool length offsets are being used and this pocket is selected This is normally a positive real number but it may be zero or any other number if it is never to be used The Diameter column contains a real number This number is used only if tool radius compensa tion is turned on using this pocket If the programmed path during compensation is the edge of the material being cut this should be a positive real number representing the measured diameter of the tool If the programmed path during compensation is the path of a tool whose diameter is nominal this should be a small number positive negative or zero representing the difference between the measured diameter of the tool and the nominal diameter If cutter radius compensation is not used with a tool it does not matter what number is in this column The Comment column may optionally be used to describe the tool Any type of description is OK This column is for the benefit of human readers only The units used for the length and diameter of the tool may be in either millimeters or inches but if the data is used by an NC program the user must be sure the units used for a tool in the file are the same as the units in effect when NC code that uses the tool data is interpreted The table shows a mixture of types of units The lines do not have to be in
120. han the number of carousel slots e the XY plane is not active e or cutter radius compensation is commanded to turn on when it is already on The behavior of the machining center when cutter radius compensation is on is described in Chapter 22 9 12 G43 G49 Tool Length Offsets To use a tool length offset program G43 H where the H number is the desired index in the tool table It is expected that all entries in this table will be positive The H number should be but does not have to be the same as the slot number of the tool currently in the spindle It is OK for the H number to be zero an offset value of zero will be used It is an error if e the H number is not an integer is negative or is larger than the number of carousel slots To use no tool length offset program G49 It is OK to program using the same offset already in use It is also OK to program using no tool length offset if none is currently being used 9 13 G53 Move in absolute coordinates For linear motion to a point expressed in absolute coordinates program G1 G53 X Y Z A B C or use GO instead of G1 where all the axis words are optional except that at least one must be used The GO or G1 is optional if it is the current motion mode G53 is not modal and must be programmed on each line on which it is intended to be active This will produce coordinated linear motion to the programmed point If G1 is active the speed of motion is the current feed rat
121. hange will save time A common programming practice for such machines is to put the T word for the next tool to be used on the line after a tool change This maximizes the time available for the carousel to move 99 Chapter 13 Order of Execution The order of execution of items on a line is critical to safe and effective machine operation Items are executed in the order shown below if they occur on the same line E Comment including message set feed rate mode G93 G94 set feed rate F set spindle speed S select tool T change tool M6 Spindle on or off M3 M4 M5 coolant on or off M7 M8 M9 MNO FR WO DN enable or disable overrides M48 M49 O dwell G4 m _ set active plane G17 G18 G19 N set length units G20 G21 jas wo cutter radius compensation on or off G40 G41 G42 A cutter length compensation on or off G43 G49 bsi al coordinate system selection G54 G55 G56 G57 G58 G59 G59 1 G59 2 G59 3 O set path control mode G61 G61 1 G64 Eu N set distance mode G90 G91 00 set retract mode G98 G99 home G28 G30 or change coordinate system data G10 or set axis offsets G92 G92 1 G92 2 G94 20 perform motion GO to G3 G33 G80 to G89 as modified possibly by G53 21 stop MO M1 M2 M30 M60 100 Chapter 14 G Code Best Practices 14 1 Use
122. he amp from a control In the HAL world the integrator must decide what HAL components are needed Usually every interface card will require a driver Additional components may be needed for software generation of step pulses PLC functionality and a wide variety of other tasks 3 1 1 2 Interconnection Design The designer of a hardware system not only selects the parts he also decides how those parts will be interconnected Each black box has terminals perhaps only two for a simple switch or dozens for a servo drive or PLC They need to be wired together The motors get connected to the servo amps The limit switches connect to the controller and so on As the machine builder works on the design he creates a large wiring diagram that shows how all the parts should be interconnected 25 CHAPTER 3 INTRODUCTION 26 When using HAL components are interconnected by signals The designer must decide which signals are needed and what they should connect 3 1 1 3 Implementation Once the wiring diagram is complete it is time to build the machine The pieces need to be acquired and mounted and then they are interconnected according to the wiring diagram Ina physical system each interconnection is a piece of wire that needs to be cut and connected to the appropriate terminals HAL provides a number of tools to help build a HAL system Some of the tools allow you to connect or disconnect a single wire Other tools allo
123. he Document you may at your option designate some or all of these sections as invariant To do this add their titles to the list of Invariant Sections in the Modified Version s license notice These titles must be distinct from any other section titles You may add a section entitled Endorsements provided it contains nothing but endorsements of your Modified Version by various parties for example statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard You may add a passage of up to five words as a Front Cover Text and a passage of up to 25 words as a Back Cover Text to the end of the list of Cover Texts in the Modified Version Only one passage of Front Cover Text and one of Back Cover Text may be added by or through arrangements made by any one entity If the Document already includes a cover text for the same cover previously added by you or by arrangement made by the same entity you are acting on behalf of you may not add another but you may replace the old one on explicit permission from the previous publisher that added the old one The author s and publisher s of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version 5 COMBINING DOCUMENTS You may combine the Document with other documents released under this License under the terms defined in section 4 above for modi
124. he R word or 2 retract perpen dicular to the selected plane to the position that axis was in just before the canned cycle started unless that position is lower than the position indicated by the R word in which case use the R word position To use option 1 program G99 To use option 2 program G98 Remember that the R word has different meanings in absolute distance mode and incremental distance mode Chapter 10 M Codes 10 1 MO M1 M2 M30 M60 Program Stopping and Ending To stop a running program temporarily regardless of the setting of the optional stop switch pro gram MO To stop a running program temporarily but only if the optional stop switch is on program M1 It is OK to program MO and M1 in MDI mode but the effect will probably not be noticeable because normal behavior in MDI mode is to stop after each line of input anyway To exchange pallet shuttles and then stop a running program temporarily regardless of the setting of the optional stop switch program M6 0 If a program is stopped by an MO M1 or M6 0 pressing the cycle start button will restart the program at the following line To end a program program M2 To exchange pallet shuttles and then end a program program M30 Both of these commands have the following effects E Axis offsets are set to zero like G92 2 and origin offsets are set to the default like G54 Selected plane is set to CANON_PLANE_XY like G17 Distance mode is
125. help on the emc developers mailing list http sourceforge net mail group_id 6744 21 CHAPTER 2 INSTALLING THE EMC2 SOFTWARE 22 2 3 EMC2 install script the easy way to install Chris Radek put together a simple script to install emc2 on Ubuntu It runs the commands ex plained in 2 4 To use it you need to Download the script from http www linuxcnc org emc2 install sh Save it on your Desktop Right click the icon select Properties Go to the Permissions tab and check the box for Owner Execute Close the Properties window Now double click the emc2 install sh icon and select Run in Terminal A terminal will appear and you will be asked for your password e When the installation asks if you are sure you want to install the EMC2 packages hit Enter to accept Now just allow the install to finish e When it is done you must reboot System gt Log Out gt Restart the Computer and when you log in again you can run EMC2 by selecting it on the Applications gt Other menu If you aren t ready to set up a machine configuration try the sim AXIS configuration it runs a simulated machine that requires no attached hardware Now that the initial installation is done Ubuntu will prompt you when updates of EMC2 or its supporting files are available When they are you can update them easily and automatically with the Update Manager 2 4 Manual installing using apt commands The following few section will describe how
126. homed the display numbers are dark green e the EMC mode is auto the auto button has a light green background e the backplotter has been turned on backplot is visible in the pop in window e the tool path from the program is showing in the display Once you start working with Mini you will quickly discover how easily it shows the conditions of the EMC and allows you to make changes to it 6 3 Menu Bar The first row is the menu bar across the top Here you can configure the screen to display additional information Some of the items in this menu are very different from what you may be acustomed to with other programs You should take a few minutes and look under each menu item in order to familiarize yourself with the features that are there The menu includes each of the following sections and subsections CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 60 Program This menu includes both reset and exit functions Reset will return the EMC to the condition that it was in when it started Some startup configuration items like the normal program units can be specified in the ini file View This menu includes several screen elements that can be added so that you can see additional information during a run These include Position Type This menu item adds a line above the main position displays that shows whether the displays are in inches or metric and whether they are Machine or Relative location and if they are Actual positions or Comm
127. hread 1 01 mSec stepgenthread 50 3 uSec Multiplier 1 Record Length C 16191 samples 1 channel C 8095 samples 2 channels 4047 samples 4 channels C 2023 samples 8 channels C 1011 samples 16 channels Figure 4 4 Realtime function not linked dialog This dialog is where you set the sampling rate for the oscilloscope For now we want to sample once per millisecond so click on the 1 03mS thread slow formerly siggen thread see footnote and leave the multiplier at 1 We will also leave the record length at 4047 samples so that we can use up to four channels at one time When you select a thread and then click OK the dialog disappears and the scope window looks something like figure 4 5 Several of these screen captures refer to threads named siggen thread and stepgen thread instead of slow and fast When the screenshots were captured the threads component didn t exist and a different method was used to create threads giving them different names Also the screenshots show pins etc as stepgen xxx rather than freqgen xxx The original name of the freqgen module was stepgen and I haven t gotten around to re doing all the screen shots since it was renamed The name stepgen now refers to a different step pulse generator one that accepts position instead of velocity commands Both are described in detail later in this document CHAPTER 4 HAL TUTO
128. ht Since we have a 4000 sample record length and are acquiring 1000 samples per second it will take halscope about 2 seconds to fill half of its buffer During that time a progress bar just above the main screen will show the buffer filling Once the buffer is half full the scope waits for a trigger Since we haven t configured one yet it will wait forever To manually trigger it click the Force button in the Trigger section at the top right You should see the remainder of the buffer fill then the screen will display the captured waveforms The result will look something like figure 4 7 XA HAL Oscilliscope CITE Horizontal Run Mode Trigger Zoom i 500 mSec 4047 samples Normal Normal Pos per div at 994 Hz C Single C Auto gt TRIGGER C Stop Force Vertical Level Pos Gain Pos a J ee eT A A Level i i i 1 div o 18 hoola ore _ rising Selected Channel 0 000 4 siggen 1 square Chan Off Source None Figure 4 7 Captured Waveforms The Selected Channel box at the bottom tells you that the green trace is the currently selected one channel 4 which is displaying the value of the pin siggen 1 square Try clicking channel buttons 1 through 3 to highlight the other three traces CHAPTER 4 HAL TUTORIAL 51 4 5 4 Vertical Adjustments The traces are rather hard to distinguish since all four are on top of each other To fix
129. ices and the license notice saying this License applies to the Document are reproduced in all copies and that you add no other conditions whatsoever to those of this License You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute However you may accept compensation in exchange for copies If you distribute a large enough number of copies you must also follow the conditions in section 3 You may also lend copies under the same conditions stated above and you may publicly display copies 3 COPYING IN QUANTITY If you publish printed copies of the Document numbering more than 100 and the Document s license notice requires Cover Texts you must enclose the copies in covers that carry clearly and legibly all these Cover Texts Front Cover Texts on the front cover and Back Cover Texts on the back cover Both covers must also clearly and legibly identify you as the publisher of these copies The front cover must present the full title with all words of the title equally prominent and visible You may add other material on the covers in addition Copying with changes limited to the covers as long as they preserve the title of the Document and satisfy these conditions can be treated as verbatim copying in other respects If the required texts for either cover are too voluminous to fit legibly you should put the first ones listed as many as fit reasonably on the actual cover and c
130. ide of Figure 7 If a path of the sort shown on the right of Figure 7 is used in which the tool does not stay in contact with the part geometry all the time the interpreter will not be able to compensate properly when undersized tools are used For a tool path contour the value for the cutter diameter in the tool table will be a small positive number if the selected tool is slightly oversized and will be a small negative number if the tool is slightly undersized As implemented if a cutter diameter value is negative the interpreter compen sates on the other side of the contour from the one programmed and uses the absolute value of the given diameter If the actual tool is the correct size the value in the table should be zero Tool Path Contour example Suppose the diameter of the cutter currently in the spindle is 0 97 and the diameter assumed in generating the tool path was 1 0 Then the value in the tool table for the diameter for this tool should be 0 03 Here is an NC program which cuts material away from the outside of the triangle in the figure N0010 Gl X1 Y4 5 make alignment move 0020 G41 Gl Y3 5 turn compensation on and make first entry move 0030 G3 X2 Y2 5 Il make second entry move N0040 G2 X2 5 Y2 J 0 5 cut along arc at top of tool path 0050 G1 Y 1 cut along right side of tool path N0060 G2 X2 Y 1 5 I 0 5 cut along arc at bottom right of tool path N0070 Gl X 2 cut along bottom side of tool path N0080 G2 X
131. in a repository on cvs linuxenc org They are available for anyone to download and use as they see fit All EMC2 files with some exceptions carry a GPL or GPLD copyright These files require that you make your source of them available to your users GPL copyright also requires that if you modify the code in that file and make a public release of your revisions you must return your modifications to the developers 1 5 How the EMC2 Works The Enhanced Machine Controller EMC2 is a lot more than just another CNC mill program It can control machine tools robots or other automated devices It can control servo motors stepper motors relays and other devices related to machine tools In this handbook we focus on only a small part of that awesome capability the minimill Figure 1 1 shows a simple block diagram showing what a typical 3 axis EMC2 system might look like This diagram shows a stepper motor system The PC running Linux as it s operating system is actually controlling the stepper motor drives by sending signals through the printer port These signals pulses make the stepper drives move the stepper motors The EMC2 can also run servo motors via servo interface cards or by using an extended parallel port to connect with external control boards As we examine each of the components that make up an EMC2 we will remind the reader of this typical machine There are four main components to the EMC2 software a motion controller EMCMOT
132. in every second Later in this tutorial we ll see how to bring those internal signals out to run motors in the real world but first we want to look at them and see what is happening 4 5 Taking a closer look with halscope The previous example generates some very interesting signals But much of what happens is far too fast to see with halmeter To take a closer look at what is going on inside the HAL we want an oscilloscope Fortunately HAL has one called halscope 4 5 1 Starting Halscope Halscope has two parts a realtime part that is loaded as a kernel module and a user part that supplies the GUI and display Before starting the GUI you must load the realtime part emc2 bin halcmd loadrt scope_rt emc2 CHAPTER 4 HAL TUTORIAL 47 Once the realtime part is loaded we can start the GUI Like halmeter you can follow it with so it runs in the background and you get your shell prompt back immediately emc2 bin halscope 2 3678 emc2 The scope GUI window will open immediately followed by a Realtime function not linked dialog that looks like figure 4 44 X A Realtime function not linked lt The HALSCOPE realtime sampling function must be called from a HAL thread in to determine the sampling rate Please do one of the following Select a thread name and multiplier then click OK or Click Quit to exit HALSCOPE Thread e Sample Period wwe Sample Rate sooo Thread Period siggen t
133. inate of the current point to be 7 The axis offsets are always used when motion is specified in absolute distance mode using any of the nine coordinate systems those designated by G54 G59 3 Thus all nine coordinate systems are affected by G92 Being in incremental distance mode has no effect on the action of G92 Non zero offsets may be already be in effect when the G92 is called If this is the case the new value of each offset is A B where A is what the offset would be if the old offset were zero and B is the old offset For example after the previous example the X value of the current point is 7 If G92 x9 is then programmed the new X axis offset is 5 which is calculated by 7 9 3 To reset axis offsets to zero program G92 1 or G92 2 G92 1 sets parameters 5211 to 5216 to zero whereas G92 2 leaves their current values alone To set the axis offset values to the values given in parameters 5211 to 5216 program G92 3 You can set axis offsets in one program and use the same offsets in another program Program G92 in the first program This will set parameters 5211 to 5216 Do not use G92 1 in the remainder of the first program The parameter values will be saved when the first program exits and restored when the second one starts up Use G92 3 near the beginning of the second program That will restore the offsets saved in the first program If other programs are to run between the the program that sets the offsets and the o
134. inate system 7 G59 2 use preset work coordinate system 8 G59 3 use preset work coordinate system 9 16 3 1 Default coordinate system One other variable in the VAR file becomes important when we think about offset systems This variable is named 5220 In the default files it s value is set to 1 00000 This means that when the EMC starts up it should use the first coordinate system as its default If you set this to 9 00000 it would use the nineth offset system as its default for startup and reset Any value other than an interger decimal really between 1 and 9 will cause the EMC to fault on startup 16 3 2 Setting coordinate system values within G code In the general programming chapter we listed a G10 command word This command can be used to change the values of the offsets in a coordinate system add here 16 4 G92 Offsets G92 is the most misunderstood and maligned part of EMC programming The way that it works has changed just a bit from the early days to the current releases This change has confused many users It should be thought of as a temporary offset that is applied to all other offsets In response to criticism of it Ray Henry studied it by comparing the way the interpreter authors expected it to work and the way that it worked on his Grizzly minimill The following quoted paragraphs are extracted from his paper which is available in several text formats in the dropbox at http www linuxcnc org CHAPTER 16 COORDINATE
135. indle This syntax is subject to change In particular to use F instead of K For instance G33 Z1 K 0625 produces a 1 inch motion in Z over 16 revolutions of the spindle This command might be part of a program to produce a 16TPI thread All the axis words are optional except that at least one must be used This will produce coordinated linear motion to the destination point at a rate dependant on the speed of the spindle It is an error if e all axis words are omitted e the spindle is not turning when this command is executed e the requested linear motion exceeds machine velocity limits due to the spindle speed CHAPTER 9 G CODES 86 9 5 G4 Dwell For a dwell program G4 P This will keep the axes unmoving for the period of time in seconds specified by the P number It is an error if e the P number is negative 9 6 G10 Set Coordinate System Data The RS274 NGC language view of coordinate systems is described in Section7 6 To set the coordinate values for the origin of a coordinate system program G10 L2 P X Y Z A B C where the P number must evaluate to an integer in the range 1 to 9 corresponding to G54 to G59 3 and all axis words are optional The coordinates of the origin of the coordinate system specified by the P number are reset to the coordinate values given in terms of the absolute coordinate system Only those coordinates for which an axis word is included on the line will be reset It is an error if
136. ing with blocks can be a challenge but some of the toys that we played with as kids can be an aid to building things with the HAL 3 4 1 Tower Pm watching as my son and his six year old daughter build a tower from a box full of random sized blocks rods jar lids and such The aim is to see how tall they can make the tower The narrower the base the more blocks left to stack on top But the narrower the base the less stable the tower I see them studying both the next block and the shelf where they want to place it to see how it will balance out with the rest of the tower The notion of stacking cards to see how tall you can make a tower is a very old and honored way of spending spare time At first read the integrator may have gotten the impression that building a HAL was a bit like that It can be but with proper planning an integrator can build a stable system as complex as the machine at hand requires 3 4 2 Erector Sets What was great about the sets was the building blocks metal struts and angles and plates all with regularly spaced holes You could design things and hold them together with the little screws and nuts 2The Erector Set was an invention of AC Gilbert CHAPTER 3 INTRODUCTION 30 I got my first erector set for my fourth birthday I know the box suggested a much older age than I was Perhaps my father was really giving himself a present I had a hard time with the little screws and nuts I really needed four arms one
137. ion to these four files there is a standard startup file Back in the early days of the EMC it was common to have to start up several different tasks in different terminal windows in order to get the EMC to run a machine Each of these tasks had to be supplied a bunch of information in the CHAPTER 1 THE ENHANCED MACHINE CONTROL 20 form of arguments in order to be certain that the task started the way that we expected it to All of this was a tedious thing All of this has been replaced with the run script file It is named simply emc This executable script file controls the startup of all of the modules needed to run a standard version of the EMC2 When run it lets the user chose a certain config to run EMC2 from Chapter 2 Installing the EMC2 software 2 1 Introduction One of the problems users often complained about EMC was installing the software itself They were forced to get sources and compile themselves and try to set up a RT patched Linux etc The developers of EMC2 chose to go with a standard distribution called Ubuntu Ubuntu has been chosen because it fits perfectly into the Open Source views of EMC2 Ubuntu will always be free of charge and there is no extra fee for the enterprise edition we make our very best work available to everyone on the same Free terms Ubuntu comes with full professional support on commercial terms from hundreds of compa nies around the world if you need those services Each new version
138. is but EMC is a complete stickler If you have ANY concavity where two lines meet at less than 180 degrees on the side that a tool of finite size cuts on EMC will stop with an error message there Even if the gouge will be 0001 deep So I always make the approach on the lead in and lead out moves such that they just nip the corner of the part a tiny bit providing an angle just over 180 degrees so that EMC won t squawk This requires some careful adjustment of the starting and ending points which are not compensated by cutter radius but must be chosen with an approximate radius in mind The operative commands are G40 Cancel Cutter compensation G41 Cutter Compensation Tool Left of Path G42 Cutter Compensation Tool Right of Path Here is a short file that cuts one side of a part with multiple convex and concave arcs and several straight cuts too It is to clamp a high speed drilling spindle to the side of the main Bridgeport spindle Most of these commands are straight from Bobcad CAM but lines N15 and N110 were added by me and some of the coordinates around those lines had to be fudged a bit by me N10 G01 G40 X 1 3531 Y3 4 N15 F10 G17 G41 D4 X 0 7 Y3 1875 COMP LEAD IN N20 XO Y3 1875 N40 X0 5667 F10 N50 G03 X0 8225 Y3 3307 RO 3 N60 G02 X2 9728 Y4 3563 R2 1875 CHAPTER 15 TOOL FILE AND COMPENSATION 111 N70 G01 X7 212 Y3 7986 N80 G02 X8 1985 Y3 2849 R1 625 N90 G03 X8 4197 Y3 1875 RO 3 N100 G01 X9 N110 G40
139. it rause gt step pii uz L pite bi selada talado dahl esla e miler TI med Figure 1 6 The XEMC Graphical Interface keep your eye on the mode display Right up there with knowing what mode is active is consistent display of the position of each axis Most of the interfaces will allow the operator to read position based upon actual or commanded position as well as machine or relative position Machine This is the position of an axis relative to the place where it started or was homed Relative This is the position of an axis after work or tool or other offsets have been applied Actual This is the real position of the axis within the machine or relative system Commanded This is where the axis is commanded to be These may all be exactly the same if no offsets have been applied and there is no deadband set in the INI file Deadband is a small distance which is assumed to be close enough perhaps one stepper pulse or one encoder pulse CHAPTER 1 THE ENHANCED MACHINE CONTROL 18 Figure 1 7 EMC2 Process Diagram PC EMC Process overly simplitied GUI G CODE ACME TkEmeg Servo to Go Card or l Printer Port Motion Control Roulieg Drivers for Axi s Motors Motors m Servo OF Stepper Machine Leadscrews Axis Actuators It is also important to see any messages or error codes sent by the EMC2 These are used by operators if they need to be reminded to change a tool to clear
140. ition and home position is set as machine zero everything will be correct Once home has been established using real machine switches or moving each axis to a known home position and issuing an axis home command g92 commands and values work as advertised These tests did not study the effect of re reading the var file while they contain numbers This could cause problems if g92 offsets had been removed with g92 1 but the var file still contained the previous numbers It is this complexity that causes us to say that G92 values must be treated as temporary They should be used to set global short term offsets The G54 59 3 coordinate systems should be used whenever long lasting and predictable offsets are needed 16 5 Sample Program Using Offsets This sample engraving project mills a set of four 1 radius circles in roughly a star shape around a center circle We can setup the individual circle pattern like this G10 L2 P1 xO yO z0 ensure that g54 is set to machine zero gO x 1 yO zO gl fl z 25 g3 x 1 yOi 1 jO gO zO m2 CHAPTER 16 COORDINATE SYSTEM AND G92 OFFSETS 118 We can issue a set of commands to create offsets for the four other circles like this G10 L2 P2 x0 5 offsets 855 x value by 0 5 inch G10 L2 P3 x 0 5 offsets g56 x value by 0 5 inch G10 L2 P4 y0 5 offsets g57 y value by 0 5 inch G10 L2 P5 y 0 5 offsets g58 y value by 0 5 inch We put these together in the following program a program for milling five
141. l Groups Motion Group 1 GO G1 G2 G3 G33 G38 2 G80 G81 G82 Coordinate System Selection G54 G55 G56 G57 G58 SSS ERA Coolant M7 M8 M9 Special case ana maybe ave at tne same time Flow Control O Non modal codes Group 0 G4 G10 G28 G30 G53 G92 G92 1 G92 2 G92 3 M100 to M199 82 Chapter 9 G Codes G codes of the RS274 NGC language are shown in Table 5 and described following that In the command prototypes the hypen stands for a real value As described earlier a real value may be 1 an explicit number 4 for example 2 an expression 2 2 for example 3 a parameter value 88 for example or 4 a unary function value acos 0 for example In most cases if axis words any or all of X Y Z A B C are given they specify a destination point Axis numbers are in the currently active coordinate system unless explicitly described as being in the absolute coordinate system Where axis words are optional any omitted axes will have their current value Any items in the command prototypes not explicitly described as optional are required It is an error if a required item is omitted In the prototypes the values following letters are often given as explicit numbers Unless stated otherwise the explicit numbers can be real values For example G10 L2 could equally well be written G 2 5 L 1 1 If the value of parameter 100 were 2 G10 L 100 would also mean the same Using real
142. l Tk programming language has been installed The Mac and Microsoft Windows version can connect to a real time EMC2 running on a Linux machine via a network con nection allowing the monitoring of the machine from a remote location Instructions for installing and configuring the connection between a Mac or Microsoft Machine and a PC running the EMC2 can be found in the integrators handbook 1 5 2 Motion Controller EMCMOT Motion control includes sampling the position of the axes to be controlled computing the next point on the trajectory interpolating between these trajectory points and computing an output to the motors For servo systems the output is based on a PID compensation algorithm For stepper systems the calculations run open loop and pulses are sent to the steppers based on whether their accumulated position is more than a pulse away from where their commanded position should be The motion controller includes programmable software limits interfaces to hardware limit and home switches SAXIS has been developed outside the EMC2 project you can find information about it at http axis unpy net CHAPTER 1 THE ENHANCED MACHINE CONTROL 13 x o Chips A EE File Edit Program View Help OlO ae b Manual Control F3 Code Entry F5 Axis ex o y NTE Continuous v 5 Home Offset TF Override Limits Spindle pi Stop Q M Brake Coolant Mist Flood Feed Override
143. liders The position is the location of the trigger point within the overall record With the slider all the way down the trigger point is at the end of the record and halscope displays what happened before the trigger point When the slider is all the way up the trigger point is at the beginning of the record displaying what happened after it was triggered The trigger point is visible as a vertical line in the progress box above the screen The trigger polarity can be changed by clicking the button just below the trigger level display Note that changing the trigger position stops the scope once the position is adjusted you restart the scope by clicking the Normal button in the Run Mode box Now that we have adjusted the vertical controls and triggering the scope display looks something like figure 4 9 CHAPTER 4 HAL TUTORIAL X A HAL Oscilliscope CES Horizontal Zoom Pos Selected Channel 500 mSec per diw TRIGGERED 2 Y_vel 4047 samples at 994 Hz Le 7 e shohihenshalisiie Run Mode Trigger Normal C Single C Stop Vertical Gain Pas E Scale 500m div Offset 0 000 Chan Off Normal C Auto Force Level Pos ENE Level 0 000 Rising Source Chan 3 Figure 4 9 Waveforms with Triggering 52 CHAPTER 4 HAL TUTORIAL 53 4 5 6 Horizontal Adjustments To look closely at part of a wave
144. ll pyramid shaped graphic that tries to show the angle you are viewing the tool path from Below it are a series of sliders that allow you to change the angle of view and the size of the plot You can rotate the little position angle display with these They take effect when you press the Refresh button The Reset button removes all of the paths from the display and readies it for a new run of the program but retains your settings for that session If backplot is started before a program is started it will try to use some color lines to indicate the kind of motion that was used to make it A green line is a rapid move A black line is a feedrate move Blue and red indicate arcs in counterclockwise and clockwise directions The backplotter with Mini allows you to zoom and rotate views after you have run your program but it is not intended to store a tool path for a long period of time 6 6 3 Tool Page The tool page is pretty much like the others You can set length and diameter values here and they become effective when you press the Enter key You will need to set up your tool information before you begin to run a program You can t change tool offsets while the program is running or when the program is paused TOOL SETUP Click or tab to adit Press enter to return to keyboard machine control TOOL NUMBER LENGTH DIAMETER COMMENT F 1 456 0 250 Drill 2 1 000 0 4968 End Mill 3 0 0 0 0 empty 4 0 0 0 0 ampty 5 0 0 0 0 empty 6 0 0 0
145. lues of the numbers I and J numbers always represent increments regardless of the distance mode setting K numbers represent increments in all but one usage see Section 9 17 8 where the meaning changes with distance mode CHAPTER 9 G CODES 93 9 18 G92 G92 1 G92 2 G92 3 Coordinate System Offsets See Section 7 6 for an overview of coordinate systems To make the current point have the coordinates you want without motion program G92 X Y Z A B C where the axis words contain the axis numbers you want All axis words are optional except that at least one must be used If an axis word is not used for a given axis the coordinate on that axis of the current point is not changed It is an error if 1 all axis words are omitted When G92 is executed the origin of the currently active coordinate system moves To do this origin offsets are calculated so that the coordinates of the current point with respect to the moved origin are as specified on the line containing the G92 In addition parameters 5211 to 5216 are set to the X Y Z A B and C axis offsets The offset for an axis is the amount the origin must be moved so that the coordinate of the controlled point on the axis has the specified value Here is an example Suppose the current point is at X 4 in the currently specified coordinate system and the current X axis offset is zero then G92 x7 sets the X axis offset to 3 sets parameter 5211 to 3 and causes the X coord
146. ly use the compiled defaults so you will certainly need to edit at least some of these files to reflect the specifics of your machine There are five kinds of configuration files INI NML TBL VAR and HAL files These are reflected in lower case file extensions to a file name They may be named EMC2 tbl or generic tbl but they do the same thing when they are read by the EMC2 as it starts up Many users copy these and name them for the specific machine that they are editing them for A set of these files named Sherlinemill ini Sherlinemill var Sherlinemill tbl and Sherlinemill nml are certainly more descriptive than a bunch of files named generic These files each contain specific information for your CNC e stepper ini contains all the machine parameters such as servo gains scale factors cycle times units etc and will certainly need to be edited e emc nml contains communication settings for shared memory and network ports you may need to override on your system although it is likely that you can leave these settings alone e stepper tbl contains the tool information such as which pocket contains which tool and the length and diameter for each tool e rs274ngc var contains variables specific to the RS 274 NGC dialect of NC code notably for setting the persistent numeric variables for the nine work coordinate systems We ll get into some of the details of these files as we begin to hook up and operate our little machine In addit
147. make_pulses To connect the functions to the proper thread we use the addf command We specify the function first followed by the thread emc2 bin halcmd addf siggen 0 update slow emc2 bin halcmd addf freqgen update_freq slow emc2 bin halcmd addf freqgen make_pulses fast emc2 After we give these commands we can run the show thread command again to see what happened emc2 bin halcmd show thread Realtime Threads Period FP Name Time Max Time 1005720 YES slow 0 0 1 siggen 0 update 2 freqgen update freq 50286 NO fast 0 0 1 freqgen make pulses emc2 Now each thread is followed by the names of the functions in the order in which the functions will run CHAPTER 4 HAL TUTORIAL 46 4 4 4 Setting parameters We are almost ready to start our HAL system However we still need to adjust a few parameters By default the siggen component generates signals that swing from 1 to 1 For our example that is fine we want the table speed to vary from 1 to 1 inches per second However the scaling of the step pulse generator isn t quite right By default it generates an output frequency of 1 step per second with an input of 1 000 It is unlikely that one step per second will give us one inch per second of table movement Let s assume instead that we have a 5 turn per inch leadscrew connected to a 200 step per rev stepper with 10x microstepping So it takes 2000 steps for one revolution of the screw and 5 revolutions to
148. mathematical operations and other expressions An expression may be evaluated to produce a number The expressions on a line are evaluated when the line is read before anything on the line is executed An example of an expression is 1 acos 0 3 4 0 2 Binary operations appear only inside expressions Nine binary operations are defined There are four basic mathematical operations addition subtraction multiplication and division There are three logical operations non exclusive or OR exclusive or XOR and logical and AND The eighth operation is the modulus operation MOD The ninth operation is the power operation of raising the number on the left of the operation to the power on the right The binary operations are divided into three groups The first group is power The second group is multiplication division and modulus The third group is addition subtraction logical non exclusive or logical exclusive or and logical and If operations are strung together for example in the expression 2 0 3 1 5 5 5 11 0 operations in the first group are to be performed before operations in the second group and operations in the second group before operations in the third group If an expression contains more than one operation from the same group such as the first and in the example the operation on the left is performed first Thus the example is equivalent to 2 0 3 1 5
149. me If only the X Y and Z axes or any one or two of them move this produces motion in a straight line hence the word linear in the term In actual motions it is often not possible to maintain constant speed because acceleration or deceleration is required at the beginning and or end of the motion It is feasible however to control the axes so that at all times each axis has completed the same fraction of its required motion as the other axes This moves the tool along same path and we also call this kind of motion coordinated linear motion Coordinated linear motion can be performed either at the prevailing feed rate or at traverse rate If physical limits on axis speed make the desired rate unobtainable all axes are slowed to maintain the desired path 7 2 5 Feed Rate The rate at which the controlled point or the axes move is nominally a steady rate which may be set by the user In the Interpreter the interpretation of the feed rate is as follows unless inverse time feed rate mode is being used in the RS274 NGC view see Section 9 19 1 For motion involving one or more of the X Y and Z axes with or without simultaneous rota tional axis motion the feed rate means length units per minute along the programmed XYZ path as if the rotational axes were not moving 2 For motion of one rotational axis with X Y and Z axes not moving the feed rate means degrees per minute rotation of the rotational axis 3 For motion of t
150. med at feed rate G1 or at traverse rate GO Inverse time feed rate G93 or units per minute feed rate G94 may be used with cutter radius compensation Under G94 the feed rate will apply to the actual path of the cutter tip not to the programmed contour Programming Instructions e To start cutter radius compensation program either G41 for keeping the tool to the left of the contour or G42 for keeping the tool to the right of the contour In Figure 7 for example if G41 were programmed the tool would stay left and move clockwise around the triangle and if G42 were programmed the tool would stay right and move counterclockwise around the triangle e To stop cutter radius compensation program G40 e If G40 G41 or G42 is programmed in the same block as tool motion cutter compensation will be turned on or off before the motion is made To make the motion come first the motion must be programmed in a separate previous block CHAPTER 15 TOOL FILE AND COMPENSATION 105 D Number The current interpreter requires a D number on each line that has the G41 or G42 word The value specified with D must be a non negative integer It represents the slot number of the tool whose radius half the diameter given in the tool table will be used or it may be zero which is not a slot number If it is zero the value of the radius will also be zero Any slot in the tool table may be selected this way The D number does not have to be the same
151. n position displays to the values that they were com manded to Machine Position sets the main position displays to the absolute distance from where the machine was homed Relative_Position sets the main position displays to show the current position including any offsets like part zeros that are active For more information on offsets see the chapter on coordinate systems Info lets you see a number of active things by writing their values into the MESSAGE pad Program File will write the currently active program file name Editor_File will write the currently active file if the editor pop in is active and a file has been selected for editing Parameter_File will write the name of the file being used for program parameters You can find more on this in the chapters on offsets and using variables for programming Tool File will write the name of the tool file that is being used during this run Active_G Codes will write a list of all of the modal program codes that are active whenever this item is selected For more information about modal codes see the introductory part programming chapter Help opens a text window pop in that displays the contents of the help file CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 61 You will notice between the info menu and the help menu there are a set of four buttons These are called check buttons because they have a small box that shows red if they have been selected These four buttons Editor
152. n the Title Page If there is no section entitled History in the Document create one stating the title year authors and publisher of the Document as given on its Title Page then add an item describing the Modified Version as stated in the previous sentence J Preserve the network location if any given in the Document for public access to a Transparent copy of the Document and likewise the network locations given in the Document for previous versions it was based on These may be placed in the History section You may omit a network location for a work that was published at least four years before the Document itself or if the original publisher of the version it refers to gives permission K In any section entitled Acknowledgements or Dedications preserve the section s title and preserve in the section all the substance and tone of each of the contributor acknowledgements and or dedications given therein L Preserve all the Invariant Sections of the Document unaltered in their text and in their titles Section numbers or the equivalent are not considered part of the section titles M Delete any section entitled Endorsements Such a section may not be included in the Modified Version N Do not retitle any existing section as Endorsements or to conflict in title with any Invariant Section If the Modified Version includes new front matter sections or appendices that qualify as Secondary Sections and contain no material copied from t
153. ne is selected treatment of the axis words is analogous In absolute distance mode the X Y R and Z numbers are absolute positions in the current coordinate system The L number is optional and represents the number of repeats L 0 is not allowed If the repeat feature is used it is normally used in incremental distance mode so that the same sequence of motions is repeated in several equally spaced places along a straight line In absolute distance mode L gt 1 means do the same cycle in the same place several times Omitting the L word is equivalent to specifying L 1 The L number is not sticky When L gt 1 in incremental mode with the XY plane selected the X and Y positions are determined by adding the given X and Y numbers either to the current X and Y positions on the first go around or to the X and Y positions at the end of the previous go around on the repetitions The R and Z positions do not change during the repeats The height of the retract move at the end of each repeat called clear Z in the descriptions below is determined by the setting of the retract mode either to the original Z position if that is above the R position and the retract mode is G98 OLD_Z or otherwise to the R position See Section 9 20 It is an error if e X Y and Z words are all missing during a canned cycle e a P number is required and a negative P number is used e an L number is used that does not evaluate to a positive i
154. ne that restores them make a copy of the parameter file written by the first program and use it as the parameter file for the second program 9 19 G93 G94 Set Feed Rate Mode Two feed rate modes are recognized units per minute and inverse time Program G94 to start the units per minute mode Program G93 to start the inverse time mode In units per minute feed rate mode an F word is interpreted to mean the controlled point should move at a certain number of inches per minute millimeters per minute or degrees per minute depending upon what length units are being used and which axis or axes are moving In inverse time feed rate mode an F word means the move should be completed in one divided by the F number minutes For example if the F number is 2 0 the move should be completed in half a minute When the inverse time feed rate mode is active an F word must appear on every line which has a Gl G2 or G3 motion and an F word on a line that does not have G1 G2 or G3 is ignored Being in inverse time feed rate mode does not affect GO rapid traverse motions It is an error if e inverse time feed rate mode is active and a line with G1 G2 or G3 explicitly or implicitly does not have an F word CHAPTER 9 G CODES 94 9 20 G98 G99 Set Canned Cycle Return Level When the spindle retracts during canned cycles there is a choice of how far it retracts 1 retract perpendicular to the selected plane to the position indicated by t
155. nteger e rotational axis motion is used during a canned cycle e inverse time feed rate is active during a canned cycle e or cutter radius compensation is active during a canned cycle When the XY plane is active the Z number is sticky and it is an error if e the Z number is missing and the same canned cycle was not already active e or the R number is less than the Z number When the XZ plane is active the Y number is sticky and it is an error if e the Y number is missing and the same canned cycle was not already active e or the R number is less than the Y number When the YZ plane is active the X number is sticky and it is an error if e the X number is missing and the same canned cycle was not already active e or the R number is less than the X number 9 17 1 Preliminary and In Between Motion At the very beginning of the execution of any of the canned cycles with the XY plane selected if the current Z position is below the R position the Z axis is traversed to the R position This happens only once regardless of the value of L In addition at the beginning of the first cycle and each repeat the following one or two moves are made 1 a straight traverse parallel to the XY plane to the given XY position 2 a straight traverse of the Z axis only to the R position if it is not already at the R position If the XZ or YZ plane is active the preliminary and in between motions are analogous CHAPTER 9 G CODES 9
156. ny I O devices have real physical pins or terminals that connect to external hard ware for example the pins of a parallel port connector To avoid confusion these are referred to as physical pins These are the things that stick out into the real world Signal In a physical machine the terminals of real hardware components are interconnected by wires The HAL equivalent of a wire is a signal or HAL signal HAL signals connect HAL pins together as required by the machine builder HAL signals can be disconnected and reconnected at will even while the machine is running Type When using real hardware you would not connect a 24 volt relay output to the 10V analog input of a servo amp HAL pins have the same restrictions which are based upon their type Both pins and signals have types and signals can only be connected to pins of the same type Currently there are 8 types as follows e BIT a single TRUE FALSE or ON OFF value e FLOAT a 32 bit floating point value with approximately 24 bits of resolution and over 200 bits of dynamic range e U8 an 8 bit unsigned integer legal values are O to 255 e S8 an 8 bit signed integer legal values are 128 to 127 e U16 a 16 bit unsigned integer legal values are O to 65535 e S16 a 16 bit signed integer legal values are 32768 to 32767 e U32 a 32 bit unsigned integer legal values are O to 4294967295 e S32 a 32 bit signed integer legal values are 2147483648
157. ock would shift the zero reference by the values stored The following line would then move each axis to the new zero position Unlike G53 G54 through G59 3 are modal commands They will act on all blocks of code after one of them has been set The program that might be run using figure 16 1 would require only a single coordinate reference for each of the locations and all of the work to be done there The following code is offered as an example of making a square using the G55 offsets that we set above G55 GO xO yO zO gl f2 z 0 2000 xl yl CHAPTER 16 COORDINATE SYSTEM AND G92 OFFSETS 115 xO yO gO zO g54 x0 yO zO m2 But you say why is there a G54 in there near the end Many programmers leave the G54 coordinate system with all zero values so that there is a modal code for the absolute machine based axis positions This program assumes that we have done that and use the ending command as a command to machine zero It would have been possible to use g53 and arrive at the same place but that command would not have been modal and any commands issued after it would have returned to using the G55 offsets because that coordinate system would still be in effect G54 use preset work coordinate system 1 G55 use preset work coordinate system 2 G56 use preset work coordinate system 3 G57 use preset work coordinate system 4 G58 use preset work coordinate system 5 G59 use preset work coordinate system 6 G59 1 use preset work coord
158. of Ubuntu receives free security updates for 18 months after release some versions are supported for even longer Ubuntu uses the very best in translations and accessibility infrastructure that the Free Soft ware community has to offer to make Ubuntu usable for as many people as possible Ubuntu is released regularly and predictably a new release is made every six months You can use the current stable release or help improve the current development release e The Ubuntu community is entirely committed to the principles of free software development we encourage people to use open source software improve it and pass it on 2 2 EMC Download Page You will find the most recent releases of EMC2 announced on www linuxcnc org The releases of EMC2 will be done in two ways sources and binary package The sources described in the Developers Handbook consist of a tarball emc2 version tar gz which you should download and unpack into your home directory This document oriented towards the end user will only try to explain how to install the binary package on the Ubuntu distribution l Ubuntu is an ancient African word meaning humanity to others Ubuntu also means I am what I am because of who we all are The Ubuntu Linux distribution brings the spirit of Ubuntu to the software world You can read more about itathttp www ubuntu com 2For information regarding other Linux variants check the Developers Handbook or ask for
159. onfigure EMC for a wide variety of hardware devices Many of the building blocks are drivers for hardware devices However HAL can do more than just configure hardware drivers 3 1 1 HAL is based on traditional system design techniques HAL is based on the same principles that are used to design hardware circuits and systems so it is useful to examine those principles first Any system including a CNC machine consists of interconnected components For the CNC machine those components might be the main controller servo amps or stepper drives motors encoders limit switches pushbutton pendants perhaps a VFD for the spindle drive a PLC to run a toolchanger etc The machine builder must select mount and wire these pieces together to make a complete system 3 1 1 1 Part Selection The machine builder does not need to worry how each individual part works He treats them as black boxes During the design stage he decides which parts he is going to use steppers or servos which brand of servo amp what kind of limit switches and how many etc The integrator s decisions about which specific components to use is based on what that component does and the specifications supplied by the manufacturer of the device The size of a motor and the load it must drive will affect the choice of amplifier needed to run it The choice of amplifier may affect the kinds of feedback needed by the amp and the velocity or position signals that must be sent to t
160. onsists of the following in order with the restriction that there is a maximum currently 256 to the number of characters allowed on a line 1 an optional block delete character which is a slash 2 an optional line number 3 any number of words parameter settings and comments 4 an end of line marker carriage return or line feed or both Any input not explicitly allowed is illegal and will cause the Interpreter to signal an error Spaces and tabs are allowed anywhere on a line of code and do not change the meaning of the line except inside comments This makes some strange looking input legal The line gOx 0 12 34y 7 is equivalent to g0 x 0 1234 y7 for example 77 CHAPTER 8 LANGUAGE OVERVIEW 78 Blank lines are allowed in the input They are to be ignored Input is case insensitive except in comments i e any letter outside a comment may be in upper or lower case without changing the meaning of a line 8 2 Line Number A line number is the letter N followed by an integer with no sign between O and 99999 written with no more than five digits 000009 is not OK for example Line numbers may be repeated or used out of order although normal practice is to avoid such usage Line numbers may also be skipped and that is normal practice A line number is not required to be used but must be in the proper place if used 8 3 Word A word is a letter other than N followed by a real value Words ma
161. ontinue the rest onto adjacent pages If you publish or distribute Opaque copies of the Document numbering more than 100 you must either include a machine readable Transparent copy along with each Opaque copy or state in or with each Opaque copy a publicly accessible computer network location containing a complete Transparent copy of the Document free of added material which the general network using public has access to download anonymously at no charge using public standard network protocols If you use the latter option you must take reasonably prudent steps when you begin distribution of Opaque copies in quantity to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy directly or through your agents or retailers of that edition to the public It is requested but not required that you contact the authors of the Document well before redistributing any large number of copies to give them a chance to provide you with an updated version of the Document 4 MODIFICATIONS APPENDIX A LEGAL SECTION 124 You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above provided that you release the Modified Version under precisely this License with the Modified Version filling the role of the Document thus licensing distribution and modification of the Modified Version to whoever possesses a cop
162. ook or other written document free in the sense of freedom to assure everyone the effective freedom to copy and redistribute it with or without modifying it either commercially or noncommercially Secondarily this License preserves for the author and publisher a way to get credit for their work while not being considered responsible for modifications made by others This License is a kind of copyleft which means that derivative works of the document must themselves be free in the same sense It complements the GNU General Public License which is a copyleft license designed for free software We have designed this License in order to use it for manuals for free software because free software needs free documentation a free program should come with manuals providing the same freedoms that the software does But this License is not limited to software manuals it can be used for any textual work regardless of subject matter or whether it is published as a printed book We recommend this License principally for works whose purpose is instruction or reference 1 APPLICABILITY AND DEFINITIONS This License applies to any manual or other work that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License The Document below refers to any such manual or work Any member of the public is a licensee and is addressed as you 122 APPENDIX A LEGAL SECTION 123 A Modified Version of the
163. or messages the numbers refer to the physical line number not the N word value 101 Chapter 15 Tool File and Compensation 15 1 Tool File The EMC uses a tool file that is read in when a machine control is started In a standard release this file is named emc var generic var or sim var and is used by the similarly named run file The specific name of the file that will be used is set by the ini file that is read at startup A tool file is required It tells which tools are in which carousel slots and what the length and diameter of each tool are The Interpreter does not deal directly with tool files A tool file is read by the EMC system and the Interpreter gets the tool information by making calls to canonical functions that obtain it The header line shown in Table 15 1 is essential for some of the graphical interfaces so it is sug gested but not required that such a line always be included as the first line in the file Each data line of the file contains the Figure 15 1 Typical Tool File data for one tool Each line has five entries The first four entries are re COMMENT quired The last entry a comment is tional It makes reading easier if 1 565 0 250 optional 1 000 0 247 Reground End Mill the entries are arranged in columns 1 125 2 000 Carbide Insert Face Mill 2S Shown in the table Dut the only AAA AA A at least one space or tab after each of the first three entries on a line and a space tab
164. or newline at the end of the fourth entry The meanings of the columns and the type of data to be put in each are as follows The POC column contains an unsigned integer which represents the pocket number slot number of the tool carousel slot in which the tool is placed The entries in this column must all be different The FMS column contains an unsigned integer which represents a code number for the tool The user may use any code for any tool as long as the codes are unsigned integers The LEN column contains a real number which represents the tool length offset This number will be used if tool length offsets are being used and this pocket is selected This is normally a positive real number but it may be zero The DIAM column contains a real number This number is used if tool radius compensation is turned on using this pocket number If the programmed path during compensation is the edge of the material being cut this should be a positive real number representing the measured diameter of the tool If the programmed path during compensation is the path of a tool whose diameter is nominal this should be a small number positive negative or zero representing the difference between the measured diameter of the tool and the nominal diameter used when the G code for the part was written 102 CHAPTER 15 TOOL FILE AND COMPENSATION 103 The COMMENT column may optionally be used to describe the tool Any type of description i
165. osine emc2 To see the effect of the 1inksp command we show the signals again CHAPTER 4 HAL TUTORIAL 44 emc2 bin halcmd show sig Signals Type Value Name float 0 00000e 00 X_vel lt siggen 0 cosine float 0 00000e 00 Y vel emc2 When a signal is connected to one or more pins the show command lists the pins immediately following the signal name The arrow shows the direction of data flow in this case data flows from pin siggen 0 cosine to signal X_vel Now let s connect the X_vel to the velocity input of a step pulse generator emc2 bin halcmd linksp X_vel freggen 0 velocity emc2 We can also connect up the Y axis signal Y_vel It is intended to run from the sine output of the signal generator to the input of the second step pulse generator emc2 bin halcmd linksp Y vel siggen 0 sine emc2 bin halcmd linksp Y vel freqgen 1 velocity emc2 Now let s take a final look at the signals and the pins connected to them emc2 bin halcmd show sig Signals Type Value Name float 0 00000e 00 X_vel lt siggen 0 cosine gt freqgen 0 velocity float 0 00000e 00 Y_vel lt siggen 0 sine gt freqgen 1 velocity emc2 The show sig command makes it clear exactly how data flows through the HAL For example the X_vel signal comes from pin siggen 0 cosine and goes to pin freqgen 0 velocity 4 4 3 Setting up realtime execution threads and functions Thinking about data flowing thr
166. ough wires makes pins and signals fairly easy to understand Threads and functions are a little more difficult Functions contain the computer instructions that actually get things done Thread are the method used to make those instructions run when they are needed First let s look at the functions available to us emc2 bin halcmd show funct Exported Functions Owner CodeAddr Arg P Users Name F 03 D89051C4 D88F10FC YES 0 siggen 0 update 02 D8902868 D88F1054 YES 0 freqgen capture_position 02 D8902498 D88F1054 NO 0 freqgen make_pulses 02 D89026F0 D88F1054 YES 0 freqgen update_freg emc2 CHAPTER 4 HAL TUTORIAL 45 In general you will have to refer to the documentation for each component to see what its functions do In this case the function siggen 0 update is used to update the outputs of the signal generator Every time it is executed it calculates the values of the sine cosine triangle and square outputs To make smooth signals it needs to run at specific intervals The other three functions are related to the step pulse generators The first one freqgen capture_position is used for position feedback It captures the value of an internal counter that counts the step pulses as they are generated Assuming no missed steps this counter indicates the position of the motor The main function for the step pulse generator is freqgen make_pulses Every time make_pulses runs it decides if it is time to take a step
167. parameter as the source for channel 1 Pins Signals Parameters siggen 1 sine siggen 1 square siggen 1 triangle stepgen 1 counts stepgen 1 dir stepgen 1 position stepgen 1 step stepgen 1 velocity stepgen 2 counts stepgen 2 dir Figure 4 6 Select Channel Source dialog To choose a signal just click on it In this case we want to use channel 1 to display the signal X_vel When we click on X_vel the dialog closes and the channel is now selected The channel 1 button is pressed in and channel number 1 and the name X_vel appear below the row of buttons That display always indicates the selected channel you can have many channels on the screen but the selected one is highlighted and the various controls like vertical position and scale always work on the selected one To add a signal to channel 2 click the 2 button When the dialog pops up click the Signals tab then click on Y_vel We also want to look at the square and triangle wave outputs There are no signals connected to those pins so we use the Pins tab instead For channel 3 select siggen 0 triangle and for channel 4 select siggen 0 square CHAPTER 4 HAL TUTORIAL 50 4 5 3 Capturing our first waveforms Now that we have several probes hooked to the HAL it s time to capture some waveforms To start the scope click the Normal button in the Run Mode section of the screen upper rig
168. parameter in the first column and the value to which that parameter should be set in the second column The value is represented as a double precision floating point number inside the Interpreter but a decimal point is not required in the file All of the parameters shown in Table 7 3 are required parameters and must be included in any parameter file except that any parameter representing a rotational axis value for an unused axis may be omitted An error will be signalled if any required parameter is missing A parameter file may include any other parameter as long as its number is in the range 1 to 5400 The parameter numbers must be arranged in ascending order An error will be signalled if not Any parameter included in the file read by the Interpreter will be included in the file it writes as it exits The original file is saved as a backup file when the new file is written Comments are not preserved when the file is written Table 7 3 Parameter File Format Parameter Number Parameter Value 5161 00 628 HomeX 5162 00 028 Home 7 6 Coordinate Systems In the RS274 NGC language view a machining center has an absolute coordinate system and nine program coordinate systems CHAPTER 7 MACHINING CENTER OVERVIEW 76 You can set the offsets of the nine program coordinate systems using G10 L2 Pn n is the number of the coordinate system with values for the axes in terms of the absolute coordinate system See Section 9 6 You can
169. put now switches from 5 0 to 5 0 and we happened to catch it switching this time 4 2 5 Saving the HAL configuration Most of what we have done with halcmd so far has simply been viewing things with the show command However two of the commands actually changed things As we design more complex systems with HAL we will use many commands to configure things just the way we want them HAL has the memory of an elephant and will retain that configuration until we shut it down But what about next time We don t want to manually enter a bunch of commands every time we want to use the system We can save the configuration of the entire HAL with a single command emc2 bin halcmd save components loadrt threads namel test thread period1 1000000 loadrt siggen signals links parameter values setp siggen 0 amplitude 5 00000e 00 setp siggen 0 frequency 1 00000e 00 setp siggen 0 offset 0 00000e 00 realtime thread function links addf siggen 0 update test thread emc2 The output of the save command is a sequence of HAL commands If you start with an empty HAL and run all these commands you will get the configuration that existed when the save command was issued To save these commands for later use we simply redirect the output to a file emc2 bin halcmd save gt saved hal emc2 4 2 6 Restoring the HAL configuration To restore the HAL configuration stored in saved hal we need to execute all of tho
170. r example after the line 3 15 3 6 has been interpreted the value of parameter 3 will be 6 If the order is reversed to 3 6 3 15 and the line is interpreted the value of parameter 3 will be 15 If the third group the comments contains more than one comment and is reordered only the last comment will be used If each group is kept in order or reordered without changing the meaning of the line then the three groups may be interleaved in any way without changing the meaning of the line For example the line g40 gl 3 15 foo 4 7 0 has five items and means exactly the same thing in any of the 120 possible orders such as 4 7 0 g1 3 15 g40 foo for the five items 8 8 Commands and Machine Modes In RS274 NGC many commands cause a machining center to change from one mode to another and the mode stays active until some other command changes it implicitly or explicitly Such commands are called modal For example if coolant is turned on it stays on until it is explicitly turned off The G codes for motion are also modal If a G1 straight move command is given on one line for example it will be executed again on the next line if one or more axis words is available on the line unless an explicit command is given on that next line using the axis words or cancelling motion Non modal codes have effect only on the lines on which they occur For example G4 dwell is non modal 8 9 Modal Groups
171. re the more generic motion controller However since EMC2 uses the HAL reconfiguration of the IO subsystem has become very powerful and flexible EMC2 contains even a Programmable Logic Controller module behaves just like a hardware PLC which can be used for very complex scenarios tool changers etc In EMC2 there is only one big I O controller which provides support for all kinds of actions and CHAPTER 1 THE ENHANCED MACHINE CONTROL 14 keystick Fi Estop On OFF PS HDI Mode PS Spndl Fud OFF ES Aborts Actions F2 Hachine On Off FA Reset Interp FAQ Spndl Rev OFF TR Selects Params F Manual Hode FF Hist Un DOFF PA Spndl Decrease HBE Quits Display Fa Auto Mode FB Flood On Off Fl Spndl Increase Toggles Help AUTO HOMED Override 100 LUBE OM cit i Tool a LUBE Ok MIST OFF Speed 560 0 Offset 0 OOO FLOOD OFF Incrt continuous Relative Act Post Program Line Command Interpretert IDLE Modal G Codes GEO 619 640 620 690 694 654 649 699 661 1 Modal M Codes Hd Ha M48 FO So e ee Figure 1 3 The Keystick interface hardware control All it s outputs and inputs are HAL logic items more on this later on so you can use only the subset which interests you or the one that fist on your hardware output e g if you have only one parallel port and no additional I O cards 1 5 4 Task Executor EMCTASK The Task Executor is responsible for interpreting G and M code programs whose behavior does not vary appreci
172. re was quite often the need to run things with root privileges Most of those things were related to the fact that HAL uses kernel modules to do much of it s work and because it also can access hardware directly Knowing that it is usually safer to avoid doing day to day work as root most of those things were reworked so that very limited root privileges are required If you are running a version of EMC2 and HAL more recent than early 2006 you can pretty much ignore this section To get around the need for root emc2 uses a small program called emc_module_helper which during the build process gets setuid status thus has root privileges This small software module takes care of the insmod rmmod commands that are needed to insert delete modules from the HAL You can use this program directly but it s lots easier to use the halemd loadrt amp unloadrt commands Here is an example of what happens when you don t have root privileges emc2 bin hal_parport 0278 PARPORT ERROR could not get I O permission emc2 As an alternative to logging in as root you can use the sudo command or the su c command The sudo command is very convenient to use and does not require you to know the root password However it needs to be configured by someone who does know the root password The configuration determines who may use sudo and what commands they can use it for We will not 33 CHAPTER 4 HAL TUTORIAL 34 discuss sudo configuration here
173. riant Sections in addition to the original versions of these Invariant Sections You may include a translation of this License provided that you also include the original English version of this License In case of a disagreement between the translation and the original English version of this License the original English version will prevail 9 TERMINATION You may not copy modify sublicense or distribute the Document except as expressly provided for under this License Any other attempt to copy modify sublicense or distribute the Document is void and will automatically terminate your rights under this License However parties who have received copies or rights from you under this License will not have their licenses terminated so long as such parties remain in full compliance 10 FUTURE REVISIONS OF THIS LICENSE The Free Software Foundation may publish new revised versions of the GNU Free Documentation License from time to time Such new versions will be similar in spirit to the present version but may differ in detail to address new problems or concerns See http www gnu org copyleft Each version of the License is given a distinguishing version number If the Document specifies that a particular numbered version of this License or any later version applies to it you have the option of following the terms and conditions either of that specified version or of any later version that has been published not as a draft by the
174. riod ServoPeriod and TrajPeriod respectively the actual times would depend on the ini That is one part of the config process and although it could be done manually it would normally be automatic The next step is to decide what each thread needs to do Some of those decisions would also be automatic the motion module would automatically connect its PlanTrajectory function to the TrajPeriod thread and its ControlMotion function to the ServoPeriod thread Other connections would be made by the integrator at least the first time These might include hooking the STG driver s encoder read and DAC write functions to the servo thread or hooking stepgen s function to the fast thread along with the parport function s to write the steps to the port 3 6 Dynamic Linking and Configuration It is indeed possible to configure HAL with a form of dynamic linking But it is different than DLLs as used by Microsoft tm or shared libraries as used in Linux Both DLLs and shared libraries essentially say Here I am I have this code you might want to use where you is other modules Then when those other modules or programs are loaded they say I need a function called X is there one and if the answer is YES they link to it With HAL a component still says Here I am I have this code you might want to use but you is the system integrator The integrator gets to decide what functions are used and doesn t have to worry about
175. rrent point and whose radius is the radius of the tool The destination point of the tool tip is then found as the center of a circle of the same radius tangent to the tan gent line at the destination point This is shown in Figure 9 If the programmed point is inside the initial cross section of the tool the circle on the left an error path of tool tip destination point of tool tip current point Second construct this line to determine the destination point programmed point First construct this line Figure 9 First Cutter Radius Compensation Move Straight A programmed centerpoint destination point of tool tip programmed end point AN Second construct this arc which is the path taken current point 108 Yo Figure 10 First Cutter Radius Compensation Move Arc is signalled Hirst construct this auxiliary arc If the first move after cutter radius compensation has been turned on is an arc the arc which is generated is derived from an auxiliary arc which has its center at the programmed center point passes through the programmed end point and is tangent to the cutter at its current location If the auxiliary arc cannot be constructed an error is signalled The generated arc moves the tool so that it stays tangent to the auxiliary arc throughout the move This is shown in Figure 10 Regardless of whether the first move is a straight line or an arc the Z axis may also mo
176. rwise it is a helical arc 9 3 2 Center format arcs In the center format the coordinates of the end point of the arc in the selected plane are specified along with the offsets of the center of the arc from the current location In this format it is OK if the end point of the arc is the same as the current point It is an error if AG when the arc is projected on the selected plane the distance from the current point to the center differs from the CHAPTER 9 G CODES 85 distance from the end point to the center by more than 0 0002 inch if inches are being used or 0 002 millimeter if millimeters are being used When the XY plane is selected program G2 X Y Z A B C I J or use G3 instead of G2 The axis words are all optional except that at least one of X and Y must be used I and J are the offsets from the current location in the X and Y directions respectively of the center of the circle I and J are optional except that at least one of the two must be used It is an error if e X and Y are both omitted e or I and J are both omitted When the XZ plane is selected program G2 X Y Z A B C I K or use G3 instead of G2 The axis words are all optional except that at least one of X and Z must be used I and K are the offsets from the current location in the X and Z directions respectively of the center of the circle I and K are optional except that at least one of the two must be used It is an error if e X
177. s OK This column is for the benefit of human readers only The units used for the length and diameter of the tool may be in either millimeters or inches but if the data is used by an NC program the user must be sure the units used for a tool in the file are the same as the units in effect when NC code that uses the tool data is interpreted The lines do not have to be in any particular order Switching the order of lines has no effect If the same pocket number is used on two or more lines which should not normally be done the data for only the last such line will persist and be used 15 2 Tool Compensation Tool compensation can cause problems for the best of nc code programmers But it can be a powerful aid when used to help an operator get a part to size By setting and reseting length and diameter of tools in a single tool table offsets can be made durring a production run that allow for variation in tool size or for minor deviation from the programmed distances and size And these changes can be made without the operator having to search through and cange numbers in a program file Throughout this unit you will find ocasional references to cannonical functions where these are nec essary for the reader to understand how a tool offset works in a specific situation These references are intended to give the reader a sense of sequence rather than requiring the reader to understand the way that cannonical functions themselves work within the
178. s called RS274 and several standard variants of it have been put forward It has also been expanded by machine tool and control builders in order to meet the needs of specific machines If a machine changed tools during a program it needed to have tool change commands If it changed pallets in order to load new castings it had to have commands that allowed for these kinds of devices as well Like any language RS274 has evolved over time Currently there are several dialects In general each machine tool maker has been consistent within their product line but different dialects can have commands that cause quite different behavior from one machine to another More recently the language of CNC has been hidden behind or side stepped by several programming schemes that are referred to as Conversational programming languages One common feature of these kinds of programming schemes is the selection of a shape or geometry and the addition of values for the corners limits or features of that geometry The use of Computer Aided Drafting has also had its affect upon the CNC programming languages Because CAD drawings are saved as a list or database of geometries and variables associated with each they are available to be interpreted into G Code These interpreters are called CAM Computer Aided Machining programs Like the CAD converters the rise of drawing programs like Corel IM and the whole bunch of paint programs converters have been written
179. s given below Changing a tool while cutter radius compensation is on is not treated as an error although it is unlikely this would be done intentionally The radius used when cutter radius compensation was first turned on will continue to be used until compensation is turned off even though a new tool is actually being used concave corner tool does not fit concave ure too small tool does not fit When cutter radius compensation is on it must be physically possible for a circle whose radius is the half the diameter given in the tool table to be tangent to the contour at all points of Figure 8 Two Cutter Radius Compensation Errors In both examples the line represents a contour and the circle represents the cross section of a the contour tool following the contour using cutter radius compensation tangent to one side of the path In particular the interpreter treats concave corners and concave arcs into which the circle will not fit as errors since the circle cannot be kept tangent to the contour in these situations This error detection does not limit the shapes which can be cut but it does require that the programmer specify the actual shape to be cut or path to be followed not an approximation In this respect the interpreter differs from interpreters used with many other controllers which often allow these errors silently and either gouge the part or round the corner If cutter radius compensation has alre
180. scale emc2 4 4 2 Connecting pins with signals What we have is two step pulse generators and a signal generator Now it is time to create some HAL signals to connect the two components We are going to pretend that the two step pulse generators are driving the X and Y axis of a machine We want to move the table in circles To do this we will send a cosine signal to the X axis and a sine signal to the Y axis The siggen module creates the sine and cosine but we need wires to connect the modules together In the HAL wires are called signals We need to create two of them We can call them anything we want for this example they will be X_vel and Y_vel To create them we use the the newsig command We also need to specify the type of data that will flow through these wires in this case it is floating point emc2 bin halcmd newsig X_vel float emc2 bin halcmd newsig Y vel float emc2 To make sure that worked we can look at all the signals emc2 bin halcmd show sig Signals Type Value Name float 0 00000e 00 X_vel float 0 00000e 00 Y_vel emc2 The next step is to connect the signals to component pins The signal X_vel is intended to run from the cosine output of the signal generator to the velocity input of the first step pulse generator The first step is to connect the signal to the signal generator output To connect a signal to a pin we use the 1inksp command emc2 bin halcmd linksp X_vel siggen 0 c
181. se HAL commands To do that we use halcmd f lt filename gt which reads commands from a file emc2 bin halcmd f saved hal emc2 4 3 Looking at the HAL with halmeter You can build very complex HAL systems without ever using a graphical interface However there is something satisfying about seeing the result of your work The first and simplest GUI tool for the CHAPTER 4 HAL TUTORIAL 39 HAL is halmeter It is a very simple program that is the HAL equivalent of the handy Fluke multimeter or Simpson analog meter for the old timers We will use the siggen component again to check out halmeter If you just finished the previous example then siggen is already loaded If not we can load it just like we did before emc2 scripts realtime start emc2 loadrt siggen emc2 loadrt threads namel test thread period1 1000000 emc2 bin halcmd addf siggen 0 update test thread emc2 bin halcmd start emc2 bin halcmd setp siggen 0 amplitude 5 emc2 4 3 1 Starting halmeter At this point we have the siggen component loaded and running It s time to start halmeter Since halmeter is a GUI app X must be running We can start halmeter in the background by following it s name with a s emc2 bin halmeter 1 22093 emc2 Since we started halmeter in the background Linux prints its process id 1 22093 and immediately returns to the shell prompt At the same time a halcmd window opens on your screen looking something like
182. spindle is turning or not Ifthe speed override switch is enabled and not set at 100 the speed will be different from what is programmed It is OK to program SO the spindle will not turn if that is done It is an error if e the S number is negative As described in Section 9 17 5 if a G84 tapping canned cycle is active and the feed and speed override switches are enabled the one set at the lower setting will take effect The speed and feed rates will still be synchronized In this case the speed may differ from what is programmed even if the speed override switch is set at 100 12 3 T Select Tool To select a tool program T where the T number is the carousel slot for the tool The tool is not changed until an M6 is programmed see Section 10 3 The T word may appear on the same line as the M6 or on a previous line It is OK but not normally useful if T words appear on two or more lines with no tool change The carousel may move a lot but only the most recent T word will take effect at the next tool change It is OK to program TO no tool will be selected This is useful if you want the spindle to be empty after a tool change It is an error if e a negative T number is used e or a T number larger than the number of slots in the carousel is used On some machines the carousel will move when a T word is programmed at the same time ma chining is occurring On such machines programming the T word several lines before a tool c
183. t When we talked about hardware design we referred to the individual pieces as parts building blocks black boxes etc The HAL equivalent is a component or HAL component This document uses HAL component when there is likely to be confusion with other kinds of components but normally just uses component A HAL component is a piece of software with well defined inputs outputs and behaviour that can be installed and interconnected as needed Parameter Many hardware components have adjustments that are not connected to any other components but still need to be accessed For example servo amps often have trim pots to allow for tuning adjustments and test points where a meter or scope can be attached to view the tuning results HAL components also can have such items which are referred to as parameters There are two types of parameters Input parameters are equivalent to trim pots they are values that can be adjusted by the user and remain fixed once they are set Output parameters cannot be adjusted by the user they are equivalent to test points that allow internal signals to be monitored Pin Hardware components have terminals which are used to interconnect them The HAL equiva lent is a pin or HAL pin HAL pin is used when needed to avoid confusion All HAL pins are named and the pin names are used when interconnecting them HAL pins are software entities that exist only inside the computer Physical_Pin Ma
184. t F2 gt has not been pressed Joe Martin says When all else fails press a software ESTOP This does everything that abort does but adds in a reset so that the EMC returns to the standard settings that it wakes up on If you have an external estop circuit that watches the relevant parallel port or DIO pin a software estop can turn off power to the motors Most of the time when we abort or EStop it s because something went wrong Perhaps we broke a tool and want to change it We switch to manual mode and raise the spindle change tools and assuming that we got the length the same get ready to go on If we return the tool to the same place where the abort was issued the EMC will work perfectly It is possible to move the restart line back or ahead of where the abort happened If you press the Back or Ahead buttons you will see a blue highlight that shows the relationship between the abort line and the one on which the EMC will start up again By thinking through what is happening at the time of the restart you can place the tool tip where it will resume work in an acceptable manner You will need to think through things like tool offsets barriers to motion along a diagonal line and such before you press the Restart button 6 5 Left Column There are two columns below the control line The left side of the screen displays information of interest to the operator There are very few buttons to press here 6 5 1 Axis Position Displa
185. that will take a bitmap or raster or vector image and turn 1One machine tool manufacturer Hurco claims to have a right to the use of these programming schemes and to the use of the term conversational when used in this context CHAPTER 1 THE ENHANCED MACHINE CONTROL 10 it into G Code that can be run with a CNC You re asking yourself Why did I want to know this The answer is that the EMC2 as is currently exists does not directly take in CAD or any image and run a machine using it It The EMC2 uses a variant of the earlier CNC language named RS 274NGC Next Generation Controller All of the commands given to the EMC2 must be in a form that is recognized and have meaning to the RS274NGC interpreter This means that if you want to carve parts that were drawn in some graphical or drafting program you will also have to find a converter that will transform the image or geometry list into commands that are acceptable to the EMC2 interpreter Several commercial CAD CAM programs are available to do this conversion At least one converter Ace has been written that carries a copyright that makes it available to the public There has been recent talk about writing a conversational or geometric interface that would allow an operator to enter programs is much the same way that several modern proprietary controls enter programs but it isn t in there yet 1 3 Computer Operating Systems The EMC2 code can be compiled on almost any GNU Linux
186. themselves recursively if it makes sense to do so The maximum subroutine nesting level is 10 11 2 Looping do while endwhile break continue The while loop has two structures while endwhile and do while In each case the loop is exited when the while condition is false draw a sawtooth shape F100 1 0 0101 while 1 1t 10 G1 X0 G1 Y 1 10 X1 1 1 1 0101 endwhile 97 CHAPTER 11 O CODES 98 Inside a while loop 0 break immediately exits the loop and 0 continue immediately skips to the next evaluation of the while condition If it is still true the loop begins again at the top If it is false it exits the loop 11 3 Conditional if else endif The if conditional executes one group of statements if a condition is true and another if it is false Set feed rate depending on a variable 0102 if 2 gt 5 F100 0102 else F200 0102 endif Chapter 12 Other Codes 12 1 F Set Feed Rate To set the feed rate program F The application of the feed rate is as described in Section 7 2 5 unless inverse time feed rate mode is in effect in which case the feed rate is as described in Section 9 19 12 2 S Set Spindle Speed To set the speed in revolutions per minute rpm of the spindle program s The spindle will turn at that speed when it has been programmed to start turning Itis OK to program an S word whether the
187. ther quantities involved in machine control cannot be changed Different quantities use different specific units Spindle speed is measured in revolutions per minute The positions of rotational axes are measured in degrees Feed rates are expressed in current length units per minute or in degrees per minute as described in Section 7 2 5 7 2 9 Current Position The controlled point is always at some location called the current position and the controller always knows where that is The numbers representing the current position must be adjusted in the absence of any axis motion if any of several events take place 1 Length units are changed 2 Tool length offset is changed 3 Coordinate system offsets are changed 7 2 10 Selected Plane There is always a selected plane which must be the XY plane the YZ plane or the XZ plane of the machining center The Z axis is of course perpendicular to the XY plane the X axis to the YZ plane and the Y axis to the XZ plane 7 2 11 Tool Carousel Zero or one tool is assigned to each slot in the tool carousel 7 2 12 Tool Change A machining center may be commanded to change tools 7 2 13 Pallet Shuttle The two pallets may be exchanged by command CHAPTER 7 MACHINING CENTER OVERVIEW 73 7 2 14 Feed and Speed Override Switches The feed and speed override switches may be enabled so they work as expected or disabled so they have no effect on the feed rate or spindle spe
188. to 2147483647 Function Real hardware components tend to act immediately on their inputs For example if the input voltage to a servo amp changes the output also changes automatically However software components cannot act automatically Each component has specific code that must be executed to do whatever that component is supposed to do In some cases that code simply runs as part of the component However in most cases especially in realtime components the code must run in a specific sequence and at specific intervals For example inputs should be lThere has been some discussion about whether we really need all the integer types Maybe they will be reduced or eliminated later Most signals and pins will be either floats or bits CHAPTER 3 INTRODUCTION 28 read before calculations are performed on the input data and outputs should not be written until the calculations are done In these cases the code is made available to the system in the form of one or more functions Each function is a block of code that performs a specific action The system integrator can use threads to schedule a series of functions to be executed in a particular order and at specific time intervals Thread A thread is a list of functions that runs at specific intervals as part of a realtime task When a thread is first created it has a specific time interval period but no functions Func tions can be added to the thread and will be executed in order
189. to install EMC2 using a console and apt commands If you know a bit about Linux and Debian flavored distributions this might be trivial If not you might consider reading 2 3 First add the repository to etc apt sources list sudo sh c echo deb http dsplabs cs upt ro emc2 breezy emc2 gt gt etc apt sources list echo deb src http dsplabs c Then update amp get emc2 axis sudo apt get update sudo apt get install emc2 axis This command will install the emc2 axis package along with all dependencies You might get warnings that the packages are from an untrusted source this means your com puter doesn t recognize the GPG signature on the packages To correct that issue the following commands gpg keyserver pgpkeys mit edu recv key BC92B87F gpg a export BC92B87F sudo apt key add 3The emc2 axis package is the AXIS gui packaged for emc2 4The dependencies are one of the nicest thing in Debian based distributions They assure you have everything installed that you need In the case of emc2 it s even a RT patched kernel and all needed libraries Part II Configuring EMC2 24 Chapter 3 Introduction 3 1 What is HAL HAL stands for Hardware Abstraction Layer At the highest level it is simply a way to allow a number of building blocks to be loaded and interconnected to assemble a complicated system The Hardware part is because HAL was originally designed to make it easier to c
190. tour is the same regardless of the actual or intended diameter of the tool Example 1 Here is an NC program which cuts material away from the outside of the triangle in figure above In this example the cutter compensation radius is the actual radius of the tool in use which is 0 5 The value for the diameter in the tool table is twice the radius which is 1 0 N0010 G41 Gl X2 Y2 turn compensation on and make entry move N0020 Y 1 follow right side of triangle N0030 X 2 follow bottom side of triangle N0040 X2 Y2 follow hypotenuse of triangle N0050 G40 turn compensation off This will result in the tool following a path consisting of an entry move and the path shown on the left going clockwise around the triangle Notice that the coordinates of the triangle of material appear in the NC code Notice also that the tool path includes three arcs which are not explicitly programmed they are generated automatically CHAPTER 15 TOOL FILE AND COMPENSATION 106 Tool Path Contour When the contour is a tool path contour the path is described in the NC program It is expected that except for during the entry moves the path is intended to create some part geometry The path may be generated manually or by a post processor considering the part geometry which is intended to be made For the interpreter to work the tool path must be such that the tool stays in contact with the edge of the part geometry as shown on the left s
191. tract a single document from such a collection and distribute it individually under this License provided you insert a copy of this License into the extracted document and follow this License in all other respects regarding verbatim copying of that document 7 AGGREGATION WITH INDEPENDENT WORKS A compilation of the Document or its derivatives with other separate and independent documents or works in or on a volume of a storage or distribution medium does not as a whole count as a Modified Version of the Document provided no compilation copyright is claimed for the compilation Such a compilation is called an aggregate and this License does not apply to the other self contained works thus compiled with the Document on account of their being thus compiled if they are not themselves derivative works of the Document If the Cover Text requirement of section 3 is applicable to these copies of the Document then if the Document is less than one quarter of the entire aggregate the Document s Cover Texts may be placed on covers that surround only the Document within the aggregate Otherwise they must appear on covers around the whole aggregate 8 TRANSLATION Translation is considered a kind of modification so you may distribute translations of the Document under the terms of section 4 Replacing Invariant Sections with translations requires special permission from their copyright holders but you may include translations of some or all Inva
192. travel one inch that means the overall scaling is 10000 steps per inch We need to multiply the velocity input to the step pulse generator by 10000 to get the proper output That is exactly what the parameter freqgen n velocity scale is for In this case both the X and Y axis have the same scaling so we set the scaling parameters for both to 10000 emc2 bin halcmd setp freqgen 0 velocity scale 10000 emc2 bin halcmd setp freqgen 1 velocity scale 10000 emc2 This velocity scaling means that when the pin freqgen 0 velocity is 1 000 the step generator will generate 10000 pulses per second 10KHz With the motor and leadscrew described above that will result in the axis moving at exactly 1 000 inches per second This illustrates a key HAL concept things like scaling are done at the lowest possible level in this case in the step pulse generator The internal signal X_vel is the velocity of the table in inches per second and other components such as siggen don t know or care about the scaling at all If we changed the leadscrew or motor we would change only the scaling parameter of the step pulse generator 4 4 5 Run it We now have everything configured and are ready to start it up Just like in the first example we use the start command emc2 bin halemd start emc2 Although nothing appears to happen inside the computer the step pulse generator is cranking out step pulses varying from 10KHz forward to 10KHz reverse and back aga
193. try man sudo and or talk to your system administrator If sudo is properly configured here is what happens emc2 sudo bin hal_parport 0278 Password lt enter your password gt PARPORT installed driver for 1 ports emc2 As an added convenience sudo remembers your password for a short time so if you enter another sudo command within the time limit usually 5 minutes you don t have to type your password again The su c command does not require configuration but does require you to know the root password and to type it in for every command You also must put quotes around the command you are trying to run emc2 su c bin hal_parport 0278 Password lt enter root password gt PARPORT installed driver for 1 ports emc2 To avoid cluttering up the examples we will not show sudo or su c Instead commands that require root privileges will be preceded by and other commands will be preceded by by emc2 ls bin emc2 bin hal_parport 0278 4 1 3 The RTAPI environment RTAPI stands for Real Time Application Programming Interface Many HAL components work in realtime and all HAL components store data in shared memory so realtime components can access it Normal Linux does not support realtime programming or the type of shared memory that HAL needs Fortunately there are realtime operating systems RTOS s that provide the neccessary extensions to Linux Unfortunately each RTOS does things a little differently To
194. unction It requires floating point It is not currently linked to any threads so users is zero 4 2 3 Making realtime code run To actually run the code contained in the function siggen 0 update we need a realtime thread Eventually halcmd will have a newthread command that can be used to create a thread but that requires some significant internal changes For now we have a component called threads that is used to create a new thread Lets create a thread called test thread with a period of 1mS 1000000nS emc2 bin halcmd loadrt threads namel test thread period1 1000000 Let s see if that worked emc2 bin halcmd show thread Realtime Threads Period FP Name Time Max Time 999849 YES test thread 0 0 emc2 It did The period is not exactly 1000000nS because of hardware limitations but we have a thread that runs at approximately the correct rate and which can handle floating point functions The next step is to connect the function to the thread emc2 bin halcmd addf siggen 0 update test thread emc2 Up till now we ve been using halcmd only to look at the HAL However this time we used the addf add function command to actually change something in the HAL We told halcmd to add the function siggen 0 update to the thread test thread and if we look at the thread list again we see that it succeeded emc2 bin halcmd show thread Realtime Threads Period FP Name Time Max Time 999849 YES test thread 0 0 1
195. ut for this example we are using only 4 at a time Before we select any more channels we need to turn off a couple Click on the channel 2 button then click the Off button at the bottom of the Vertical box Then click on channel 3 turn if off and do the same for channel 4 Even though the channels are turned off they still remember what they are connected to and in fact we will continue to use channel 3 as the trigger source To add new channels select channel 5 and choose pin stepgen 1 dir then channel 6 and select stepgen 1 step Then click run mode Normal to start the scope and adjust the horizontal zoom to 5mS per division You should see the step pulses slow down as the velocity command channel 1 approaches zero then the direction pin changes state and the step pulses speed up again You might want to increase the gain on channel 1 to about 20m per division to better see the change in the velocity command The result should look like figure 4 11 XA HAL Oscilliscope CTE Horizontal Run Mode Trigger Zoom _ J 500mSec 4047 samples Normal Normal Pos per div at 19 9 KHz C Single C Auto _ _ TRIGGERED C Stop Force Vertical Level Pos Gain Pos Scale Level i 0 000 Rising Selected Channel Source 5 stepgen 1 step Chan Off Chan 3 Figure 4 11 Looking at Step Pulses Part III Using EMC2 56 Chapter 5
196. ve at the same time It will move linearly as it does when cutter radius compensation is not being used Rotary axis motions A B and C axes are allowed with cutter radius compensation but using them would be very unusual After the entry moves of cutter radius compensation the interpreter keeps the tool tangent to the programmed path on the appropriate side If a convex corner is on the path an arc is inserted to go around the corner The radius of the arc is half the diameter given in the tool table When cutter radius compensation is turned off no special exit move takes place The next move is what it would have been if cutter radius compensation had never been turned on and the previous move had placed the tool at its current position Programming Entry Moves In general an alignment move and two entry moves are needed to begin compensation correctly However where the programmed contour is a material edge contour and there is a convex corner on the contour only one entry move plus possibly a pre entry move is needed The general method which will work in all situations is described first We assume here that the programmer knows what the contour is already and has the job of adding entry moves General Method The general method includes programming an alignment move and two entry moves The entry moves given above will be used as an example Here is the relevant code again N0010 Gl X1 Y4 5 make aligment move to point
197. w you to save a complete list of all the parts wires and other information about the system so that it can be rebuilt with a single command 3 1 1 4 Testing Very few machines work right the first time While testing the builder may use a meter to see ifa limit switch is working or to measure the DC voltage going to a servo motor He may hook up an oscilloscope to check the tuning of a drive or to look for electrical noise He may find a problem that requires the wiring diagram to be changed perhaps a part needs to be connected differently or replaced with something completely different HAL provides the software equivalent of a voltmeter oscilloscope signal generator and other tools for testing and tuning a system The same commands used to build the system can be used to make changes as needed 3 1 2 Summary This document is aimed at people who already know how to do this kind of hardware system integration but who do not know how to connect the hardware to EMC The traditional hardware design as described above ends at the edge of the main control Outside the control are a bunch of relatively simple boxes connected together to do whatever is needed Inside the control is a big mystery one huge black box that we hope works HAL extends this traditional hardware design method to the inside of the big black box It makes device drivers and even some internal parts of the controller into smaller black boxes that can be
198. wo or three rotational axes with X Y and Z axes not moving the rate is applied as follows Let dA dB and dC be the angles in degrees through which the A B and C axes respectively must move Let D y d4 dB dC Conceptually D is a measure of If the parallelism requirement is violated the system builder will have to say how to distinguish clockwise from counter clockwise CHAPTER 7 MACHINING CENTER OVERVIEW 72 total angular motion using the usual Euclidean metric Let T be the amount of time required to move through D degrees at the current feed rate in degrees per minute The rotational axes should be moved in coordinated linear motion so that the elapsed time from the start to the end of the motion is T plus any time required for acceleration or deceleration 7 2 6 Coolant Flood coolant and mist coolant may each be turned on independently The RS274 NGC language turns them off together see Section 10 4 7 2 7 Dwell A machining center may be commanded to dwell i e keep all axes unmoving for a specific amount of time The most common use of dwell is to break and clear chips so the spindle is usually turning during a dwell Regardless of the Path Control Mode see Section 7 2 15 the machine will stop exactly at the end of the previous programmed move as though it was in exact path mode 7 2 8 Units Units used for distances along the X Y and Z axes may be measured in millimeters or inches Units for all o
199. y begin with any of the letters shown in Table 8 1 The table includes N for completeness even though as defined above line numbers are not words Several letters I J K L P R may have different meanings in different contexts Table 8 1 Words and their meanings AA axis ona ne C_ Caxis ofmachine SSO Z offset for arcs and G87 canned cycles Spindle Motion Ratio for G33 synchronized movements Miscellaneous function See table 7 Dwell time in canned cycles and wi 4 Key used with G10 8 3 1 Number The following rules are used for explicit numbers In these rules a digit is a single character between O and 9 e A number consists of 1 an optional plus or minus sign followed by 2 zero to many digits followed possibly by 3 one decimal point followed by 4 zero to many digits provided that there is at least one digit somewhere in the number CHAPTER 8 LANGUAGE OVERVIEW 79 e There are two kinds of numbers integers and decimals An integer does not have a decimal point in it a decimal does e Numbers may have any number of digits subject to the limitation on line length Only about seventeen significant figures will be retained however enough for all known applications e A non zero number with no sign as the first character is assumed to be positive Notice that initial before the decimal point and the first non zero digit and trailing after the decimal point and the last non zero digit zeros ar
200. y of it In addition you must do these things in the Modified Version A Use in the Title Page and on the covers if any a title distinct from that of the Document and from those of previous versions which should if there were any be listed in the History section of the Document You may use the same title as a previous version if the original publisher of that version gives permission B List on the Title Page as authors one or more persons or entities responsible for authorship of the modifications in the Modified Version together with at least five of the principal authors of the Document all of its principal authors ifit has less than five C State on the Title page the name of the publisher of the Modified Version as the publisher D Preserve all the copyright notices of the Document E Add an appropriate copyright notice for your modifications adjacent to the other copyright notices F Include immediately after the copyright notices a license notice giving the public permission to use the Modified Version under the terms of this License in the form shown in the Addendum below G Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document s license notice H Include an unaltered copy of this License I Preserve the section entitled History and its title and add to it an item stating at least the title year new authors and publisher of the Modified Version as given o
201. ys The axis position displays work exactly like they do with tkemc The color of the letters is important e Red indicates that the machine is sitting on a limit switch or the polarity of a min or max limit is set wrong in the ini file e Yellow indicates that the machine is ready to be homed e Green indicates that the machine has been homed The position can be changed to display any one of several values by using the menu settings The startup or default settings can be changed in the ini file so these displays wake up just the way that you want them 6 5 2 Feedrate Override Immediately below the axis position displays is the feedrate override slider You can operate feed rate override and feedhold in any mode of operation Override will change the speed of jogs or feed rate in manual or MDI modes You can adjust feed rate override by grabbing the slider with your mouse and dragging it along the groove You can also change feed rate a percent at a time by clicking in the slider s groove In auto mode you can also set feed override in 10 increments by pressing the top row of numbers This slider is a handy visual reference to how much override is being applied to programmed feedrate CHAPTER 6 USING THE MINI GRAPHICAL INTERFACE 65 6 5 3 Messages The message display located under the axis positions is a sort of scratch pad for the EMC If there are problems it will report them there If you try to home or move an axis when the ES
202. ys also when we think of the length of the toy asa measure of the time taken to get from one end to the other A very different thread or backbone is created by connecting the same set of hubs with different length rods The total length of the backbone can be changed by the length of rods used to connect the hubs The order of operations is the same but the time to get from beginning to end is very diferent 3 4 4 A Lego Example When Lego blocks first arrived in our stores they were pretty much all the same size and shape Sure there were half sized one and a few quarter sized as well but that rectangular one did most of 3Tinkertoy is now a registered trademark of the Hasbro company 4The Lego name is a trademark of the Lego company CHAPTER 3 INTRODUCTION 31 the work Lego blocks interconnected by snapping the holes in the underside of one onto the pins that stuck up on another By overlapping layers the joints between could be made very strong even around corners or tees I watched my children and grandchildren build with legos the same legos There are a few thousand of them in an old ratty but heavy duty cardboard box that sits in a corner of the recreation room It stays there in the open because it was too much trouble to put the box away and then get it back out for every visit and it is always used during a visit There must be Lego parts in there from a couple dozen different sets The little booklets that came with them are long

Download Pdf Manuals

Related Search

Related Contents

Construcción - Tierra Mia CA  Instruction Manual 使用说明书 取扱説明書  OPERATING MANUAL - quarta-rad  Doser correctement vos produits détergents  TL-WN821N Adaptateur USB sans fil N  0 Manuel d`utilisation - ODK - CRF  D2825-32 Brushless Motor User Manual    SIMON 24 (LS)  

Copyright © All rights reserved. Failed to retrieve file