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1. A rtisan Artisan Technology Group is your source for quality TecmoogyGroup new and certified used pre owned equipment FAST SHIPPING AND SERVICE CENTER REPAIRS WE BUY USED EQUIPMENT DELIVERY Experienced engineers and technicians on staff Sell your excess underutilized and idle used equipment TENS OF THOUSANDS OF at our full service in house repair center We also offer credit for buy backs and trade ins IN STOCK ITEMS www artisantg com WeBuyEquipment 7 EQUIPMENT DEMOS HUNDREDS OF InstraV ea REMOTE INSPECTION LOOKING FOR MORE INFORMATION MANUFACTURERS Remotely inspect equipment before purchasing with Visit us on the web at www artisantg com 7 for more our interactive website at www instraview com information on price quotations drivers technical LEASING MONTHLY specifications manuals and documentation RENTALS ITAR CERTIFIED D a gaa tia Contact us 888 88 SOURCE sales artisantg com www artisantg com DMC 300 10 DC MOTOR CONTROLLER User s Manual June 1988 TABLE OF CONTENTS 1 Overview 2 Getting Started 2 1 System Elements 2 2 Connecting the Elements 2 3 Design Examples 3 System Compensation 4 Communication 4 1 Handshake 4 2 Address Selection 5 Instruction Set 6 Modes of Motion 6 1 Profiled Positioning 6 2 Incremental Mode 6 3 Velocity Mode 7 Special Modes of operation 7 1 Local Mode 7 2 Position Latch 7 3 Stop from Run 7 4 Re2. OF n Offset of n Range 0 127 TM n Controller sample time in microseconds Range 500 65000 TL n Torque limit Limits the output voltage to the range between 10 n 128 and 10 n 128 If motor cannot run at specified speed due to TL limit the commanded speed slows down in order to limit the position error to 1024 Range 0 127 denotes that command can be applied while motor is moving Control Modes SV Servo Mode System controls the position and corrects for errors continuously SH Servo Here Enables transition from Motor Off MO to servo mode Current motor position is defined as desired position MO Motor Off Mode The position is monitored continuously but the motor command is turned off This mode is useful when the motor shaft has to be turned manually Use SV to return to the original command position or SH to servo at the current position VM n Velocity Mode Specify parameter to define speed magnitude and direction Range 4 to 250000 counts sec Resolution is 4 counts Note The actual speed is 1000 1024 of the command speed DH n Defines the current and commanded position specified by n Range 8x106 SN n Stop from Run Stops motion a distance n counts after a low input on the start stop line Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Accuracy is SP 2000 n must be greater than SP 2000 SPI 2 AC FE Find Edge This command is us
3. The Y axis status registers occupy address N 6 The Z axis data registers occupy address N 8 The Z axis status register is address N 10 Communication between the DMC 300 and the VME Bus controller can be explained conceptually if one imagines two mailboxes an Incoming mailbox and an Outgoing mailbox The VME Bus controller can only receive mail or send mail when the corresponding mailbox flag is up If the VME Bus controller wants to receive mail it would check the Incoming mailbox flag When the flag is up the host can take the mail After the mail is removed the flag goes down and the host can take no more mail until the flag is put up again by the DMC 300 Similarly the host can send mail to the DMC 300 via the outgoing mailbox If the flag is up mail can be put in the box If the flag is down no mail can be put in the box The flags must be checked after every character is sent or received Handshake For each axis the handshake is done by the lowest 2 bits of the status register These bits are denoted by W and R MSB Status byte 76543210 WR The status bits indicate when a data byte is to be read and when the DMC 300 is ready to receive data The procedure is as follows When W 1 The DMC 300 is ready to receive a data byte When W 0 The DMC 300 is busy and cannot receive data When R 0 The DMC 300 has a data byte in the read data register to be read by the VME Bus Artisan Technology Group Quality Instru
4. 888 88 SOURCE www artisantg com A rtisan Artisan Technology Group is your source for quality TecmoogyGroup new and certified used pre owned equipment FAST SHIPPING AND SERVICE CENTER REPAIRS WE BUY USED EQUIPMENT DELIVERY Experienced engineers and technicians on staff Sell your excess underutilized and idle used equipment TENS OF THOUSANDS OF at our full service in house repair center We also offer credit for buy backs and trade ins IN STOCK ITEMS www artisantg com WeBuyEquipment 7 EQUIPMENT DEMOS HUNDREDS OF InstraV ea REMOTE INSPECTION LOOKING FOR MORE INFORMATION MANUFACTURERS Remotely inspect equipment before purchasing with Visit us on the web at www artisantg com 7 for more our interactive website at www instraview com information on price quotations drivers technical LEASING MONTHLY specifications manuals and documentation RENTALS ITAR CERTIFIED D a gaa tia Contact us 888 88 SOURCE sales artisantg com www artisantg com
5. The actual response of the system is then observed using the DMM 900 card By observing the system response on an oscilloscope it is possible to select the best filter coefficients experimentally The ideal response has fast risetime minimum overshoot and no oscillations Curve a represents a slow underdamped response that can be improved by larger values of GN and ZR Response b is ideal Response c is underdamped and requires reduced gain Integrator Once the system GN ZR and PL are adjusted for the best system dynamic performance the integrator may be used to improve static accuracy Gradually increase KI until the position error at stop is zero You can monitor the position error by entering TE Tell Error If KI is too high the system will oscillate and become unstable Torque Limit The torque limit TL instruction will limit the magnitude of the motor command The normal range of the motor command is between 10V and 10V The range can be limited between a and a volts Suppose that we command TLn This limits the magnitude to a volts where 10n a Volts 128 The limit on the motor command limits the motor torque TL can also be viewed as a software adjustable current limit if the amplifier is a current amplifier The default value of TL is 127 Sampling Time The sampling time can be changed with the instruction TM The command TMn will increase the sampling time from 500 vs to n vs n gt 500 The change in samp
6. holding mode Normally the controller starts at the SV servo holding mode However if MOF is jumpered the default value is MO motor off The DE jumper allows differential inputs of an incremental encoder CHA and CHB to be input Differential inputs are useful when the effect of encoder noise needs to be minimized When a differential encoder is used the DE jumpers must be removed Appendix D Pin Out JX JY JZ 1 Ground 2 Sequence Complete 3 4 Motion Complete 5 Ground 6 Error 7 Forward Limit Switch 8 Reverse Limit Switch 9 Remote Local 10 Stop Start Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com 11 Ground 12 Direction Reverse Forward 13 Sign 14 Abort 15 Ground 16 PWM 17 Encoder Phase A 18 Encoder Phase B 19 5V 20 Encoder Phase A 21 Ground 22 Encoder Phase B 23 12V 24 12V 25 Ground 26 Motor Command Active Low Inputs Encoder Phase A Phase B Position feedback from incremental encoder with two channels in quadrature Phase A and Phase B Any resolution encoder may be used as long as the maximum frequency not exceed 250 000 quadrature states sec The DMC 300 performs quadrature decoding of the encoder signals resulting in a resolution of quadrature counts 4 x encoder cycles Encoder Phase A Phase B Differential encoder inputs If used must properly configure DMC 300 Refer to Appendix C Abort A low input stops motion instantly
7. return the SS1 ES1 RR and RD flags will be cleared If the limit switch in the direction of the motion is activated the motion stops and the controller exits from the incremental mode 6 3 Velocity Mode This mode is specified with the VM command In this mode an end position is not specified and the motor slews at the specified speed until a stop ST command is issued The acceleration and jog speed are specified using the AC VM or SP command respectively The direction of motion is specified by the sign of the VM parameter or using DF or DR commands Motion begins on the Begin command The speed may be changed at any time during motion The speed acceleration and direction of motion may be changed at any time during motion The IP n command can also be used to instantly change the motor position Upon receiving this command the motor will instantly try to servo to a position which is equal to the increment n plus the current position Important Note When using the SN command in the velocity mode the acceleration cannot be changed Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com on the fly It should be noted that the DMC 300 operates as a position controller even while in the jog mode The DMC 300 converts the speed and acceleration profile into a position trajectory A new position target is specified every 5 msec This method of control results in very precise speed r
8. without a controlled deceleration Reset A low input resets the state of the processor to its power on condition Forward Limit Switch Low input inhibits motion in forward direction Reverse Limit Switch Low input inhibits motion in reverse direction Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Remote Local Selects the control mode local or remote In the local mode the DMC 300 ignores all remote commands Stop Start When input is low the motor accelerates to the slew speed When input goes high the motor decelerates to a stop This input is ignored unless in the local mode or when SS1 or ES1 commands are given Direction Reverse Forward Selects direction of motion in the local mode or when the DS1 or FE command is given in the remote mode Active Low APPENDIX I Noise Considerations Gali controllers are microprocessor based where the processor is fetching instructions from memory in a controlled sequence Electrical disturbances such as from power supply disturbances noise on input lines or ground loops could cause the microprocessor to execute instructions erroneously or hang up Such a condition could cause motor runaway which might result in system damage It is strongly recommended that the engineer eliminate potential noise sources in the design process A few guidelines are provided here 1 Power Supply Disturbances If there is noise on
9. 128 1152 128 9 Step 2 Convert the result into binary 9 decimal 00000100 1 binary Step 3 Let A7 through A15 denote the binary result Then jumper the bits represented by zero Bits represented by one leave open JUMPER CONFIGURATION A15 A14 A13 A12 All A10 A9 A8 A7 XXXXX0XXO0 X Jumpered 0 Open NOTE The default address n of the DMC 300 is FF81 H 65409 which is represented by all bits one no jumpers Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com 5 INSTRUCTION SET The DMC 300 provides an extensive instruction set for programming a variety of motion profiles An instruction consists of two letters followed by an applicable parameter number All instructions are uppercase and sent one character at a time in ASCII A semicolon or carriage return terminates the instruction Example PR 4000 PR is the 2 character instruction code for position relative 4000 is the parameter which represents the required position value The terminates the instruction The instructions are grouped according to function and described below The commands noted with the can be applied while the motor is moving Control Parameters GN n Gain of digital filter Range 0 255 except for 1 ZR n Zero of digital filter Range 0 255 PL n Pole of digital filter Range 0 255 KI n Integrator of digital filter Range 0 127 DB n Deadband of n Range 0 127
10. DMC 300 card in an empty double height VME card slot and secure top and bottom with screws Make sure the DMC 300 is configured with appropriate options before inserting into VME card cage See Appendix C 4 Resecure system cover and tighten screws if applicable 5 Insert the 26 pin ribbons to the JX DMC 300 320 and 330 JY DMC 320 330 and JZ DMC 330 connectors Ends of the cable should be terminated appropriately to system components Step 2_ _Establishing Communication After you have installed the DMC 300 controller you should establish communication between the controller and host computer Refer to Chapter 4 for communication procedure Once you have established communication the computer display should Please consult the factory if you do not receive a show a colon Please consult the factory if y after pressing the carriage return or enter key Step 3 Connecting the Encoder The ICB 930 interconnect card easily connects the DMC 300 to other system elements such as the encoder If you are using the ICB 930 interconnect card simply connect the ribbon cab le from the controller to the JI connector of the interconnect card Be sure that the connector edge with the arrow corresponds to pin 1 If you also purchased a motor encoder from Gali simply connect the encoder to the 10 pin keyed connector on the ICB 930 card With other encoders connect the encoder signals to the pins marked PHA and PHB The ICB930 al
11. Off on Error Turns the motor command off when n 1 and the position error exceeds that specified by the ER error limit This mode is motor off MO Use SV or SH to turn the mol or back on n 0 turns off the off on error feature Range 0 or 1 PD n Position Dump If n l position reporting mode activated Change in position from previous sample is reported every sample The range of numbers is between 127 and 127 The numbers are reported as a single byte It is the responsibility of the user to read the reported position every sample period In the reporting mode the controller may receive commands but will not send responses to them For example ST stops the motion while TP results in no response Position reporting is stopped with PO 0 Numbering System DC Input numbers in decimal output in HEX HX Input in HEX output in HEX NOTE Negative numbers are input as signed negative numbers Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Interrogate TP Tell Position Reports the absolute position as a 6 digit hexadecimal number 2 s complement TE Tell Error Reports the position error as a 4 digit hexadecimal number 2 s complement TV Tell Velocity Reports actual motor velocity as 6 digit hexadecimal number 2 s complement This output is roundedto the nearest 2048 counts sec TI Tell inputs and status In response the system reports a 2 digit hexadecimal num
12. an limit them to a trapezoidal velocity The operation in the incremental mode is as follows Suppose that the motor position must follow an arbitrary trajectory x t shown in Fig 6 4 The motion time is then divided into increments of At and the corresponding increments in position are denoted by Ax The position trajectory is specified by the increments Ax once per interval The controller then integrates the Ax increments The time interval At has a minimum value of 0 5 ms and the value of Ax is limited to the range between 127 and 127 The controller can operate in either the normal mode or the incremental mode While in the incremental mode it can only receive the Ax values and no other communication can be performed The default mode of operation is the normal mode To activate the incremental mode use the command IM In the incremental mode all transmitted data is interpreted as Ax increments To exit from the incremental mode simply command 80H and that returns the controller back to the normal mode In the incremental mode the value of the increment is sent as a single byte When using bus communication the handshake consists of reading the write bit DI of address N 1 If D 1 data can be sent The controller will not respond with a colon after each transmitted byte Upon return to normal mode there will be no colon and the controller will be in the velocity mode where the direction is the last direction command sent Upon
13. aranteed 888 88 SOURCE www artisantg com 7 3 Stop from Run The instruction SN n is used to stop a distance n counts from the position at which a transition in input occurs Upon a low input must be low for at least 5 msec on the start stop input a new profile with n as the target distance will be created The motor will come to a stop at a location n counts away from input The accuracy in counts is given by SP 2000 The restriction on n is as follows n gt SP 2000 SP2 2 AC The SN n instruction must be respecified for each move 7 4 Repeat Modes A set of commands have been implemented to allow for automatic repetition of a move The user may specify the number of times the move is to be repeated or the DMC may be commanded to repeat indefinitely A pause lasting from 1 millisecond to 30 seconds may be inserted between moves by using the WT command The motion may be repeated in one direction using the repeat RP n command or it can be stepped back and forth by the repeat reverse RR n command Example interpretation PR 100 Specify step size WT 1000 Specify wait time in msec between moves RR 10 Repeat Reverse move 10 times BG Begin move sequence 7 5 Find Edge The Find Edge FE instruction is useful for initializing the system to a Home switch To enter this mode specify FE followed by BG Upon Begin the motor slews at the specified speed until a transition occurs on the direction input The motor will then in
14. ber The 8 decoded bits represent the following status Bit 7 Executing Sequence 6 Executing Move 4 REV limit switch 0 Excessive position error__ TT Tell Torque Reports the motor command as a 2 digit 2 s complement number Example TT Response Motor Command TC Tell Code Allows the user to determine why the motor stops The controller responds with the stop code as follows 00__ Motor is running no stop command received __ 03 ID ecelerating or stopped by REV limit switch 04 Decelerating or stopped by Stop Command ST 06 Stopped by Abort Input 08 Decelerating or stopped by Off on Error OE1 _ 09 Stopped after finding edge FE _ Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com 11 Stopped after input but n too small SN n RD n Reports H to the command port when motion command is complete and if n l Range 0 or 1 TS Reports the latched position captured with LT I command Other SM n Sign Magnitude Sets the mode of the motor command When n O the PWM output is 0 duty cycle for full negative voltage 50 for 0 voltage and 99 6 for full positive voltage When n l the PWM signal is 0 for 0 voltage 99 6 for full voltage and the sign of the motor command is available at the sign output Range 0 or 1 RS Resets the controller to default values All position counters are initialized to zero ER n Error Li
15. d where needed 2 GETTING STARTED 2 1 System Elements Before you start you must get all the necessary elements These include 1 DMC 300 Series controller Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com 2 DC Motor with 2 channel incremental encoder for each axis 3 Motor driver for each axis 4 Power supply for drivers 5 VME Bus power supply for controller 5V 12V 12V 6 Host computer 7 Cable Set CC 3 I O cables Helpful but not necessary 8 ICB 930 interconnect board for each axis 9 DMM 900 position monitor 10 Oscilloscope Motor The motor may be brush type or brushless of any size The motor should be properly sized to move the load at the required speed and acceleration The power driver should also be sized for the motor and load Power Driver The driver should be suitable for the motor and may be linear or pu ise width modulated A driver may have current feedback or voltage feedback The driver should accept an analog signal in the 10V range as a command The amplifier gain should be set so that a IOV command will generate the maximum required current For example if the motor peak current is 10A the amplifier gain should be 1 A V Encoder The encoder must be TTL with two channels in quadrature A differential encoder may also be used Appendix C It is easier when a rotary encoder is mounted directly on the motor shaft however other forms
16. ed to reference the system to an external switch Following the FE and BG command the motor slews at the specified speed until a transition occurs on the direction switch Pin 12 of Jl The direction of motion is defined by the initial level of the direction switch IM Incremental Mode Allows arbitrary position trajectory to be specified Disables controller profiler Use IM to specify mode Use 80 hex to terminate mode While in the incremental mode controller can receive only position increment values and no other communication can be performed Profiling Parameters PR n Specifies target distance of n counts relative to current command position Units are quadrature counts Range 8x106 PA n Specifies target position to absolute position n This position is referenced from the absolute zero Range 8x106 SP n Specifies speed rate in counts sec for velocity and position mode Resolution is 4 counts sec Range 0 250000 Note The actual speed is 1000 1024 of the commanded speed AC n Specifies acceleration and deceleration rate in units of counts sec Resolution is 4096 counts sec only when in VM mode Range 0 1 3x108 DF Specifies direction as FWD in VM mode SS n Start motion on switch if n 1 and when stop start input Pin 10 of Jl goes low following BG command SSO disables function Range 0 or 1 ES n End motion in switch of n 1 and when stoplstart input Pin 10 of Jl goes high Range 0 or 1 OE n
17. egulation with phase lock accuracy 7 SPECIAL MODES OF OPERATION 7 1 Local Mode This mode permits velocity control by local switches To operate in this mode provide a low voltage to the Remote local input Pin 9 on J1 The local mode uses the following inputs Input Description Remote local Selects local mode Direction REV FWD Selects direction of motion Stop Start Starts and stops motion FWD limit switch Inhibits motion in FWD direction RVS limit switch Inhibits motion in RVS direction Abort Stops motion instantaneously To start motion bring the stop start input low The motor will accelerate to the specified slew speed The direction of motion is determined by the direction input The motor decelerates to a stop when the stop start input is brought high The speed and acceleration will be at the specified values programmed during remote operation or the default values 7 2 Position Latch The controller can latch the motor position and store it in a special register This position can be interrogated later The latch function can be armed with the instruction LT1 and disarmed with LTO Once the latch is armed it will capture the motor position if the start stop input line is held low for a minimum of 5 msec Once the position is latched the function is disarmed The latched position can be interrogated with the instruction TS Tell Saved Position Artisan Technology Group Quality Instrumentation Gu
18. is reduced the slew time will decrease In the limiting case of PR 160 the slew time is zero Shorter moves will result in triangular velocity profiles with the same acceleration and lower peak velocities Increment Position The IP n command may be used while the motor is moving to specify a new position target The new end position is equal to the old end position plus the increment n Upon receiving the IP command a revised profile will be generated for motion towards the new end position The position increment n must be in the same direction of motion The IP command does not require a begin Note If the motor is not moving the IP n command is equivalent to the PR and BG command combination For example the instructions PR 2000 SP 10000 AC 40000 BG can be immediately followed with the instruction IP 1000 which sets the total distance to 3000 counts Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com If the IP command is issued while the motor is on the final deceleration toward the position 2000 the motor accelerates again to the required velocity A typical velocity profile is shown in Fig 6 3 The IP n instruction can also be given while the motor is at rest no BG is required IP cannot be used in the velocity mode VM 6 2 Incremental Mode The controllers can be operated in an incremental mode that allows them to follow an arbitrary position profile rather th
19. istance of 10 000 counts at a slew speed of 20 000 counts sec and an acceleration rate of 100 000 count s2 Instruction Interpretation PR 10000 Distance SP 20000 Speed AC 100000 Acceleration BG Start motion In response the motor turns and stops Example 2 Absolute Position Objective Command motion be specifying the absolute position as 7000 counts from zero Instruction Interpretation PA 7000 Set the desired absolute position BG Start motion 3 SYSTEM COMPENSATION The DMC 300 provides digital compensation with programmable Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com coefficients GN PL ZR and KI These parameters can be adjusted for optimum performance This step is the most critical one as it stabilizes the system without a tachometer The Gain term GN affects the system stiffness The Zero term ZR provides damping The integrator KI affects accuracy and eliminates position error at stop The exact mathematical model of the filter is given in Appendix F The DMC 300 filter parameters are set at the following values on power up GN 8 ZR 232 PL O KIO These will provide adequate performance for several motor systems If your motor and load have high inertias you may find it better to gradually increase the value of zero This can be done by the command ZR N Set Zero N Similarly the value of the pole PL can be selected by the command PL N Se
20. ling time has several effects on the system First it lowers the motor speed by a factor of n 500 It also lowers the motor acceleration by the ratio n 500 2 A secondary effect is on the digital filter It introduces longer delay that will normally result in less stable systems After a change in TM the filter parameters have to be re adjusted for best performance Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com 4 COMMUNICATION The VME Bus controller communicates with the DMC 300 as it would with any I O card The address N of the DMC 300 card only is selectable by a set of jumpers labeled A7 through A15 The default address of the card is FF81 H Communication is in the form of ASCII characters all letters must be uppercase sent one character at a time with a handshake procedure as described below The DMC 300 has registers which are used for communication via the VME bus For each axis of motion two registers are read only registers and the third is write only The write only register is used to transmit data to the DMC 300 The read only registers are used to receive data from the DMC 300 and to read the status byte which is required for the handshake The read data register and the write data register of the X axis occupy the same address N in the I O address space The read status register occupies the next address N 2 The Y axis data registers occupy address N 4
21. lowed by CR LF and For all other valid instructions the response is If the instruction is not valid or cannot be recognized the response is 4 The flow chart in Fig 4 1 shows the sequence for writing to and from the DMC 300 Address Selection The DMC 300 controls 1 axis denoted by X only The DMC 320 controls 2 axis denoted by X and Y The DMC 330 controls 3 axis of motion denoted by X Y and Z Each axis of motion has a separate address as follows ADDRESS DESCRIPTION X AXIS DATA X AXIS STATUS Y AXIS DATA Y AXIS STATUS Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com N 8 Z AXIS DATA Z AXIS STATUS The address N can be every 128th number between 129 and 65409 Note The controller card will occupy 128 bytes of the I O address space However only 6 addresses are used in the controller communication The selection of the address N is done by placing tje appropriate jumpers on the jumpers labeled A7 through A15 Since the allowable addresses of the DMC 300 start as 129 A7 through A15 denote the 27 through 215 bits of an address For example to select an address N first make sure N 1 is divisible by 128 Next use jumpers A7 through A15 to represent the binary result A jumper across Ax respresents a binary zero An open across Ax represents binary one Example Select address N of the DMC 300 as 1153 Step I Check if N 1 is divisible by
22. mand HX isused and to send commands in decimal DC is HEX number 3FA71B would be 3 1048576 15 65536 10 4096 7 256 1 16 11 4171547 decimal Note Negative hex values are represented as 2 s complement quantities For example 111111 hex is 1 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com decimal Appendix B Pulse Width Modulation Besides the analog motor command the DMC 300 produces two types of pulse width modulated signals which can be used to directly drive an amplifier The forms are for a chopper or an inverter amplifier configuration In the inverter form the PWM signal will be 50 duty cycle for 0 current 0 duty cycle for full negative current and 99 6 duty cycle for full positive current This method of driving an amplifier has the advantage of being very linear but it is not very power efficient The DMC 300 will produce this form of PWM if SMO is specified If SM1 is specified then the form of PWM is the chopper form In this form the PWM duty cycle represents the magnitude of current while the sign of the current is contained in the SIGN signal Zero or low is for positive current one or high is for negative current This form of PWM is more power efficient but is nonlinear Appendix C Jumpers The DMC 300 has two options that can be jumpered These are marked MOF and DE The MOF jumper affects the default value of the
23. mentation Guaranteed 888 88 SOURCE www artisantg com controller This data byte must be read before the DMC 300 can receive new data When R 1 The DMC 300 READ data register is empty NOTE A data byte is one ASCII character The status byte includes 2 more bits Bit 2 is one when the sequence is complete for that axis and bit 3 is zero when the position error exceeds 1024 counts for that axis To send each character in an instruction the__status byte must always be checked for the appropriate bit conditions Failure to do so could result in lost or erroneous data Communication The basic rules of communication by the VME bus are the following 1 The user may read the output byte whenever R O Similarly whenever W 1 the user may write an input byte It is a good practice to read the output byte before writing so that when the DMC has to echo a response the output buffer is empty 2 The DMC 300 reads one byte at a time and decodes it Since the communication is done on a low priority basis the transfer rate is approximately 100 us byte During acceleration the transfer rate is longer approximately 500 us byte Also the decoding of the CR or is equivalent in length to 5 bytes of data 3 A command instruction to the DMC 300 controller must be terminated by a carriage return CR or The response of the DMC 300 is as follows For instructions requiring data such as TP TE TI the response will include the data fol
24. mit Specifies the position error limit as n counts Whenever this limit is exceeded the error output will indicate that Range 0 1023 LT n Latch Position n 1 arms position latch Captures motor position if the start stop input is held low for a minimum of 5 msec Once the position is latched the function is disarmed Read latched position with TS command Range 0 or I Interrogate It is possible to interrogate the system with the commands TQ Report torque command level GN Report gain ZR Report zero PL Report pole DB Report deadband OF Report offset command level Default Parameters Upon reset the system starts in a position control servo mode SV If the MOF is jumpered the default mode is motor off MO The digital filter default values are GN 8 ZR 232 PL O and KI O Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com The motor command mode is bipolar SM n n 0 and the default values of the speed and acceleration are SP 32768 AC 65536 6 MODES OF MOTION The DMC 300 controller can operate in various modes of motion including profiled positioning incremental positioning and jogging In all of these modes the DMC 300 must be in servo operation 6 1 Profiled Positioning In this mode the acceleration rate AC slew speed SP and end position PA or PR is specified On Begin BG the DMC 300 generates a trapezoidal or t
25. nd ground are connected to pins 3 and 2 respectively Adjust the offset trimmer TS until the motor stops For other amplifiers and motors consult the appropriate documentation for proper connections and offset adjustments Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Before connecting the controller output to the amplifier input type the command OE 1 CR This instruction shuts off the motor command when the position error exceeds 1024 counts It will inhibit the motor from running away if it is not connected properly Also command the instruction GN 1 CR This reduces the gain of the control system to the minimum value Now you can close the loop by applying the motor command signal from the controller to the amplifier When the ICB 930 is used with the ESA amplifier connect the pin of the J4 connector marked MCMD to pin 7 of the amplifier The GND pin should be connected to pin 9 of the amplifier only if the amplifier supply is floating in reference to the controller supply With other amplifiers apply the motor command signal to the amplifier in a similar manner When the control loop is closed there is a 50 probability that the feedback polarity is wrong When that is the case the position error increases toward 1024 counts causing the controller to shut off the motor The red LED will also be lit If this condition occurs simply reverse the feedback polarity by reve
26. of coupling are possible The limitation on the encoder line density is that if the encoder has N cycles per revolution the maximum frequency of the encoder must be limited to 62 5 KHz For example if N 1000 pulses rev the maximum motor velocity is 62 5 rev s or 3750 rpm The interface between the DMC 300 and the motor encoder is simplified greatly if the ICB 930 interconnect board is used especially when the encoder and the motor are purchased from Gali You need one ICB 930 for each axis Motion Monitor Understanding the system behavior becomes easier if you use the DMM900 monitor This monitor Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com decodes the motor position from the optical encoder and displays it as one digital byte It also converts the position to an analog signal which can be displayed on an oscilloscope The analog display allows you to see if the system overshoots or oscillates An alternative to the DMM 900 is a potentiometer that can be attached to the motor shaft Now that you have all these parts ready you can proceed to the first step 2 2 Connecting the Elements Step 1 Installing the DMC 300 The DMC 300 may be installed directly into the VME double height backplane The simple procedure is outlined below 1 Make sure all power to the system is off Unplug power cord from your system 2 Expose the VME card cage to allow access to it 3 Insert
27. peat Mode 7 5 Find Edge Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com 8 Error Handling Appendices A Decimal to Hex Conversion B Pulse Width Modulation C Jumpers D Pin Out E Pin Description I Noise Considerations 1 OVERVIEW The DMC 300 series is a VME bus compatible motion controller for 1 2 or 3 DC motors The DMC 300 controls one axis the DMC 320 and DMC330 control two and three axes Each product is configured as a VMr _ bus compatible I 0 card As a true general purpose controller the DMC 300 series can operate in numerous modes including point to point positioning and jogging Several commands are provided including instructions for specifying the motor position velocity and acceleration The motion generated is along trapezoidal velocity profiles and the velocity level can be changed on the fly For each axis controlled the DMC 300 accepts position feedback from an incremental encoder No additional velocity feedback is required because the controller implements a digital filter for stability The coefficients of the filter are programmable allowing for optimum dynamic performance For each axis the DMC 300 produces a 10 volt range analog output which is input to a power amplifier of any size NOTE This manual will refer to all products in the DMC 300 series as the DMC 300 The DMC 300 DMC 320 DMC 330 specific features will be note
28. riangular velocity profile and position trajectory An example velocity profile and position trajectory is shown in Fig 6 1 A new command position along the profile is generated every 5 msec Motion is complete when the last position command or target position is generated by the DMC 300 The actual motor motion may not be complete at this point A new Begin command for the next move may not be given until motion is complete The speed can be changed at any time during motion The acceleration cannot be changed during positioning A stop command can be issued at any time to decelerate the motor to a stop before it reaches its final position Instruction Interpretation PR 500 Specify position as 500 counts SP 10000 Specify speed as 10000 counts sec AC 500000 Specify acceleration as 500000 counts sec BG Begin motion The following example generates a periodic motion in one direction The velocity profile is shown in Fig 6 2 PR 1000 Move a step size of 1000 counts SP 4000 Slew velocity 4000 counts s Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com AC 100000 Acceleration 100 000 counts sl WT 200 Wait time 200 ms RP Repeat indefinitely The resulted motion will have an acceleration time of Ta SP AC 4000 100000 0 04s The slew time Ts is found from SP ta ts 1000 or ts 0 21 sec To terminate the motion input the command ST STOP If the step size
29. ror condition These signals include Signal or Function State if Error Occurs Status Register Bit 3 Goes low Error Output Line Goes low OE Function Shuts motor off 8 3 Off on Error The software command off on error OE1 turns the motor off when the position error exceeds 1024 or the limit set by the ER command The profile being executed is also aborted To re enable the system Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com use the reset RS servo SV or servo here SH command To activate the OE function specify 1 0 disables off on error 8 4 Stop Code The instruction TC Tell Code allows the user to determine why a motor stops The controller responds with the stop code as follows Code Meaning 00 Motor is running no stop command was received 01 Stopped at commanded position 02 Decelerating or stopped by FWD limit switches 03 Decelerating or stopped by REV limit switches 04 Decelerating or stopped by Stop command ST 05 Decelerating or stopped by End on Switch ES1 06 Stopped by Abort Input 07 Stopped by Abort AB 08 Decelerating or stopped by off on error OE1 09 Stopped after finding edge FE 10 Stopped n counts from input SM n 11 Stopped after input but n too small SN n Appendix A Decimal to Hex Conversion The Hexadecimal numbering system base 16 is used in addition to the decimal system in the DMC oe send commands in hex the com
30. rsing either the motor wires or the encoder channels Once the correct feedback polarity is established repeat Step 4 by first typing RS Reset The motor should remain at the initial position The position of the motor may be interrogated with the instruction TP CR In response to that the controller reports the position Under normal conditions the position should be near zero Repeat the above procedure for each motor in your system For the DMC 320 the outputs and inputs for each axis are distinguished by X Y For the DMC 330 the outputs and inputs are denoted by X Y Z Step 5 Compensation Once the loop has been closed it is necessary to adjust the filter parameters GN ZR PL KI A simple procedure is to gradually increase the gain GN until the position error is minimized This can be done for example with the instruction GN 6 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com which increases the gain to 6 The resulting system accuracy may be interrogated with the instruction TE CR which responds with the position error As the gain is increased the position error decreases proportionately If the system starts to oscillate lower the gain A more detailed discussion is given in Section 3 and in Appendix F 2 3 Design Examples The following examples illustrate the use of the DMC 300 controller Example 1 Profiled Move Objective Rotate the motor a d
31. so provides 5V supply and GND to power the encoder Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com These signals are available on the appropriately marked pins If you are not using the ICB 930 interconnect board connect the encoder signals to the JX JY and JZ connectors as follows Signal Pin on JX JY JZ Channel A 20 Channel B 22 SV 19 GND 21 Once the encoder is connected rotate the motor shaft Mdnually and interrogate the position with the instruction TP lt carriage return gt The controller response should vary as the motor is turned The position reported will be in two s complement Hexadecimal Make sure you enter commands in uppercase For example at position zero the response to TP is TP lt carriage return gt 000000 For the DMC 320 and DMC 330 repeat the above procedure for the X Y and Z axis encoders Step 4 Connecting the Motor and the Amplifier For best results the amplifier should operate as a current source with no additional compensation The gain of the amplifier should be such that a IOV command results in the MdXimum required current If you are using a voltage amplifier consult Galil The first step is to connect the motor to the amplifier and to adjust the offset signal so that with no input command the motor stops When using the ESA amplifier from Gali Motion Control connect the motor to pins 1 and 4 The supply voltage a
32. stantly come to a stop For a decelerated stop use the End on Switch command ES1 and stop input The direction of motion is defined by the initial level of the direction switch 8 ERROR HANDLING The DMC 300 provides several features to check for error conditions and to inhibit the motor on error These features help protect the various system components from damage Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com 8 1 Hardware Protection The DMC 300 includes hardware input and output protection lines for various error and mechanical limit conditions These include Output Protection Lines m This signal goes low when the position error exceeds the value specified by the error limit command ER Input Protection Lines aoe K low input stops motion instantly without a controlled deceleration Also aborts motion profile Low input inhibits motion in forward direction Low input inhibits motion in reverse direction 8 2 Programmable_Error Limit The DMC 300 provides a programmable error limit The error limit can be set for any number between 1 and 1023 by using the ER n command The units of the error limit are quadrature counts The error is the difference between the command position and actual encoder position If the absolute value of the error exceeds the value specified by ER the DMC 300 will generate several signals to warn the host system of the er
33. t Pole N The gain can also be increased using GN N noting that as the gain increases the system performance improves up to a certain gain value and then the system becomes underdamped and finally even unstable To determine the best values of ZR PL and GN start with a low value of GN and increase it gradually until the system overshoots then reduce the gain slightly For best resolution the gain should be between 20 and 200 If the gain is too low you can increase its value by lowering the amplifier gain by the same proportion Similarly if the system is stable for GN 255 you can increase the amplifier gain This will result in lower values for the controller gain GN Another method for selecting the ZR and GN parameters is by observing the step response The motor is commanded to step back and forth and its position response is monitored by the DMM 900 from Gali The output of the DMM 900 is displayed on an oscilloscope for easy analysis of system performance The system is commanded to step back and forth by the following instructions Instruction Interpretation PR 40 Move 40 counts must be small step WT 50 Wait 50 msec at the end of move RR Repeat move indefinitely BG Begin motion sequence Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com When using the step response test it is a good idea to command a small step such as 40 counts to prevent roll over of the DMM 900
34. your power supply apply large filter capacitors i e 500 microfarad near the location where power enters the controller board Ferrite beads can also be used 2 Noise on General and Switch Inputs You can add ferrite beads and capacitors to minimize noise disturbance on inputs A better approach is to use opto isolators near the controller on each input line 3 Ground Loops A ground loop can occur when a magnetic field passes throuah the ground path inducing a current this can be avoided by connecting grounds in a tree structure If you are shielding components all shields must beterminated only at one end 4 Encoder Noise Erroneous counting due to encoder noise is prevented from the controller filtering circuitry However in extremely noisy environments extra protection can be achieved by using differential encoders 5 Catastrophic Failure Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com To protect your hardware from controller failures it is a good idea to connect mechanical limits and emergency stop inputs to the amplifier in addition to the controller To further protect the system against amplifier failures it is advised to connect the motor to the amplifier by a relay Whenever the extreme mechanical limits are activated the relay will disconnect the motor from the amplifier and short its leads Artisan Technology Group Quality Instrumentation Guaranteed
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