Application Note:QCI-AN034 QuickSilver Controls, Inc. Rotary Knife
Contents
1. MD 43 Mrs 23 TMD 45 Krs 24 Krsa 30 MMD 46 Mn 19 EGM Run EGM in modulo mode to automatically repeat every Mn Electronic Gearing Mode Acc Factor in AF 40 Scale Factor in SF 41 Trapezoid Move Enabled Start Position SP in Register 42 Master Distance MD in Register 43 Master Ramp Distance MRD in Register 44 Trapezoid Move Distance TMD in Register 45 Modulo Master Distance MMD in Register 46 Override Existing Move Relative Master Position Modulo Enabled EGM is launched and runs in the background while the Main Loop is executed for user specific code QuickSilver Controls Inc Page 7 of 14 Application Note QCI AN034 QuickSilver Controls Inc Rotary Knife Simple Dynamic qcp Requires eae e QuickControl 4 64 Pe ae Rotation e SilverDust Firmware 37 m nite The following is an overview of Rotary Knife Simple Dynamic qcp This is very similar to Rotary Knife Simple Fixed qcp except the EGM command is not run in modulo mode but instead is executed every Mn to allow for Mn to change on the fly i e using an HMI This program file is composed of the following programs Init Same as Rotary Knife Simple Fixed qcp except Mn can be thought of as an initial value Home to Index Same as Rotary Knife Simple Fixed qcp Rotary Knife F command EGM is executed for each Mn or in other words for each Rota Knife Operation knife revolution Each pass throu2. Mark 49 Reg Mark 48 Jump to LOOP Command Stop Motion acc 40000 cps s vel 0 cps Wait On Bit State Until Trajectory Active is LOW FALSE Disable Multi Tasking Wait Forever This allows somebody to use Real Time Trace to detect where the program is at Jump to 0 Application Note QCI AN034 QuickSilver Controls Inc Rotary Knife Simple SN qcp The following is an overview of Rotary Knife Simple SN qcp This is ER very similar to Rotary Knife Simple Dynamic qcp except it is written for Po a Rotation the SilverNugget Instead of the EGM command the SilverNugget uses the RSD command The SilverNugget does not support the extended calculation commands CLD CLX so the calculations usually require a little more code Servo Knife This program file is composed of the following programs Init Same as Rotary Knife Simple Dynamic qcp except as noted above Home to Index Same as Rotary Knife Simple Dynamic qcp except as noted above Rotary Knife This program switches the Registered Step and Direction RSD command s Scale Factor SF between the Cut Segment Scale Factor SFcs and the Return Segment Scale Re calculate Mrs in case Mn has changed Accumulator 10 Mn 19 Accumulator 1 0 Accumulator 1 0 Mcs 25 Return Segment Scale Factor SFrs Scale Factor SF E a lait E Start Return Segment Factor SFrs Mis Mn Mes for RS The desired knife movement is Krs the rest of t
3. Application Note QCI AN034 QuickSilver Controls Inc Date 18 July 2008 www QuickSilverControls com Rotary Knife Included files e QCI AN034 Rotary Knife pdf This document Rotary Knife Simple Fixed qcp Rotary Knife Simple Dynamic qcp Rotary Knife Registration qcp Rotary Knife Simple SN qcp Introduction Rotary knife systems are widely used to cut seal or perforate material moving along a conveyor Rotary knife system consists of a cylinder with a knife blade fastened along the longitudinal axis As the cylinder rotates it cuts the material passing underneath it During the cut the tangential knife velocity must match the linear speed of the material During the rest of the revolution the knife must either speed up or slow down to be ready for the next cut Most rotary knife applications are continuous operation with material continuously moving along the conveyer belt The knife axis slave is geared electronically to the feed axis master so that the material cut lengths are independent of the material feed speed Property of QuickSilver Controls Inc Page 1 of 14 This document is subject to change without notice QuickControl and QCI are Registered Trademarks of QuickSilver Controls Inc SilverLode SilverNugget SilverDust PVIA QuickSilver Controls and AntiHunt are trademarks of QuickSilver Controls Inc Application Note QCI AN034 QuickSilver Controls Inc This document will dis
4. Number of knife encoder counts for Cut Segment CS This is somewhat arbitrary It needs to be long enough to clear the material at both ends It also needs to be long enough to allow the knife to settle into matching speed prior to engaging the material The following is a good default number Kes Kepr 4 e Knife Return Segment Krs Knife encoder counts for Return Segment RS This is just the rest of the knife s rotation Krs Kcpr Kcs e Cut Segment Scale Factor SFcs Scale Factor SF for CS The Rotary Knife is an electronic gearing application therefore a key calculation that needs to be made is the EGM command s Scale Factor SF SF is basically a gear ratio between the knife slave and master See Application Note QCI AN019 Electronic Gearing for more information The general equation of SF is SF SF1 GR where SF1 is SF for a 1 1 ratio In other words if SF SF1 the knife axis would move the same number of encoder counts as the master SF1 is not user settable and is automatically calculated in the program QuickSilver Controls Inc Page 3 of 14 Application Note QCI AN034 QuickSilver Controls Inc Gear Ratio GR is the slave axis movement knife encoder counts movement over the given master axis movement master encoder counts that synchronizes the knife to material passing beneath it GR should be less than 1 0 for smooth operation GRs of 1 0 and greater will require servo tuning Therefore the Cut S
5. ams see app note SF 41 SFes 18 AF 40 SF 41 LO 1000 Write 0 to SP 42 Register MD 43 Mrs 23 MRD 44 MD 43 LO 100 MRD 44 Max of MRD 44 or 1 TMD 45 Krs 24 Krsg 30 Electronic Gearing Made Acc Factor in AF 40 Scale Factor in SF 41 Trapezoid Move Enabled Start Position SP in Register 42 Master Distance MD in Register 43 Master Ramp Distance MRD in Register 44 Trapezoid Move Distance TMD in Register 45 Modulo Master Distance MMD in Register 46 Override Existing Move Relative Master Position One Trapezoid Move Only Wait for one full rotation Accumulator 10 Target Position O Kepr 13 Jump to 1 If Last Cale Was Negative TRUE Modulo Knife Targ Kepr 13 Pos Kepr 13 Loop forever Jump to LOOP Application Note QCI AN034 QuickSilver Controls Inc T2 Queue Mn Reading the RMS and queuing up the Mn s is done in the controller s 2nd program thread This is actually a separate program running in parallel to the thread 1 programs Init Home to Index and Rotary Knife See Multi Thread in User Manual for details This program calculates the Mn s and pushes them onto a queue to be later popped off and used by the Rotary Knife program The queue is first set to hold a maximum of 50 Mn s The Main Loop waits for RMS to go HIGH and then saves the master encoder position reg 200 into a user register Reg Mark Mn is calculated by comparin
6. cuss two types of rotary knife applications Simple and Registration Direction of Rotation Knife In the Simple application the material length is Pa Ye fixed in the program or selected by an operator iieis and the cuts are made continuously Feed Master Direction of Encoder Rotation Knife Material ae Rotary Knife Simple Feed Teod o The Registration application adds a Registration Mark Sensor RMS that detects a registration mark on the material where the cut is to be made The material length is variable and the RMS may be several material lengths Rotary Knife Registration from the knife Master i Encoder Registration Marks Registration Mark Sensor RMS QuickSilver Controls Inc Page 2 of 14 Application Note QCI AN034 QuickSilver Controls Inc Rotary Knife Simple The material feed is continuous The knife speed matches the material speed Sidi Sar keti for the Cut Segment CS and then Segment Kcs depending on Material Length Mn C Knife Radius R speeds up or slows down during the ie gt Mrs lt gt i lt I Mcs Return Segment RS to get into position for the next cut lg gt Mn t Mn is set by the operator or hard coded in the program i eoa Application Specific Parameters e Knife Counts Rev Kcpr Kcpr is the number of knife encoder counts for 1 revolution of the Knife Kcpr lt user defined gt e Knife Cut Segment Kcs
7. e QCI AN034 QuickSilver Controls Inc Rotary Knife This program uses the EGM command to run in the rotary knife function in the background Knife Return Segment Geared Krsg is the distance the knife would move during the RS if it stay geared at the synchronous scale factor of SFcs This is used as a base distance to calculate how much more or less the EGM command s Mapezele Move feature needs to move during the RS to be ready for the next cut Label Command Krsg Mrs GR Mrs SFcs SF1 Note that we have to use the 64 bit multiple and divide to not overflow the 32 bit registers The EGM Trapezoid Move Registers define the distance the knife will move during the RS e Start Position SP 0 Start immediately e Master Distance MD Mrs e Move Ramp Distance MRD MD 100 Nice easy acc dec e Trapezoid Move Distance TMD Krs Krsg The distance TMD is the extra distance the knife will travel during the RS Note this is in addition to the distance traveled as normal electronic gearing Krsg Negative values of TMD mean the knife will rotate slower than during the CS e Master Modulo Distance MMD Mn Modulo every Mn Rotary Knife Operation Knife Return Segment Geared Krsg Distance Knife will move during Mrs due to GR Krsg Mrs GR Krsg Mrs SFes 10 000 000 T64L 38 U64 Mrs 23 SFes 18 Krsg 30 T64L 38 U64 1 0000000 EGM Params see app note Write 0 to SP 42 Register
8. egment Scale Factor SFcs is as follows SFcs SF1 GR SFcs SF1 Kcs Mcs GR Kcs Mcs lt 1 0 e Material Length Mn Material Length in Master Encoder Counts In the Rotary Knife Simple Fixed qcp example Mn is fixed at the beginning of the program file In the Rotary Knife Simple Dynamic qcp example Mn can changed from a host i e HMI in real time Mn lt user defined gt e Master Cut Segment Mcs Master encoder counts for CS Mcs is calculated from Kcs using GR Mcs Kcs GR Mcs Kes SF1 SFcs e Master Return Segment Mrs Master encoder counts for RS Mrs Mn Mcs QuickSilver Controls Inc Page 4 of 14 Application Note QCI AN034 QuickSilver Controls Inc Setup 1 Initialize the servo as described in the User Manual chapter 1 The application assumes the knife rotates in the servo s positive Servo direction You may need to edit the DIR command in the Pee Ce Initialization Wizard to change the servo s positive direction Knife 2 Attach the servo to the knife axis aligning the encoder index SSS with the knife blade at the end of the Cut Segment This can be done by either physically aligning the index mark on the motor s shaft or by running a program to make the motor move to its index See the example file included with QuickControl QCI Examples Homing Routines Home To Encoder Index qcp 3 Wire the servo for electronic gearing by connecting the master encoder A B signals to t
9. g the current Reg Mark with the Last Reg Mark Mn Reg Mark Last Reg Mn is then forced to be within the user defined min max Mn is pushed onto Q If more than 50 Mn s are pushed onto the queue thread 1 is forced to load and run the Fault program and thread 2 halts Fault Fault stops the servo and enters an infinite loop The infinite loop keeps the program running which is nice when using QuickControl s Real Time Trace feature to identify what the program is doing QuickSilver Controls Inc Page 12 of 14 Label Command PUSH GOOD Thread 2 Queue Up Material Lengths Mn Initialize Mn Queue Init Queue Mn Q 50 Size 50 Accumulator 1 0 Size Clear Last Reg Mark 49 Main Loop Wait for Reg Mark RMS Wait On Bit Edge Until 1 0 1 is HIGH TRUE Reg Mark 48 External Encoder Position 200 Mn This RM Last RMS Accumulator 10 Reg Mark 48 Last Reg Mark 49 Clip Between Mmin and Mmax Accumulator 10 Min of Accumulator 10 or Mmax 32 Accumulator 10 Max of Accumulator 10 or Mmin 31 Push onto Queue Fault if push fails Mn Q 50 Head lt Accumulator 1 0 Accumulator 10 Size Jump to PUSH GOOD If Last Cale Was Zero TRUE Fault Force Thread 1 to fault and halt program here Force Load and Run in Thread 1 Program Fault Wait Forever This allows somebody to use Real Time Trace to detect where the program is at Jump to 0 Push Good Last Reg
10. gh Main Loop is one LOOP Main Loop revolution Re calculate Mrs in case Mn has changed Mrs Mn Mcs Mrs 23 Mr 19 Mes 25 Mrs is re calculated in case Mn has changed lier el ry istance Knife will move during Mrs due to GR Krsg Mrs GR Krsg Mrs SFes 10 000 000 T64L 38 U64 Mrs 23 SFcs 18 Krsg 30 T64L 38 U64 1 0000000 EGM Params see app note Write 0 to SP 42 Register MD 43 Mrs 23 5 7 5 MRD 44 MD 43 LO 100 The EGM Trapezoid Move Registers define the distance the se ert a as knife will move during the RS All the parameters are the TMD 45 Krs 24 Krsa 30 i i 3 x i i Electronic Gearing Mode same Rotary Knife Simple Fixed qcp except there is no Acc Factor in AF 40 Scale Factor in SF 41 MMD and EGM is configured execute only one Trap Move Tiavard Move crated Start Position SP in Register 42 Master Distance MD in Register 43 Master Ramp Distance MAD in Register 44 Trapezoid Move Distance TMD in Register 45 Modulo Master Distance MMD in Register 46 Override Existing Move Relative Master Position While EGM is executing the program waits for one Doe opezi Maa Do P ey Wait for one full rotation complete revolution of the knife After which the knife s Accum deter 10 Tasgot Postiont0 Kegst a ae position is modulo down by one revolution and we jump ipo back to the start for the next pass Modulo Knife Targ Kepi 13 Pos Kep
11. he knife rotation While the knife goes the distance Krs the ee aa master must move the rest of material pass the knife The ig Accumulator 10 F1 23 material distance Mcs has already passed therefore the Accumulator 10 Accumulator 10 Krs 24 f Accumulator 10 Accumulator 10 Mrs 23 master just has to move Mrs Mn Mcs SFrs is therefore cC SF 28 Accumulator 10 Wait for Return Segment to pass y Accumulator 1 0 Target Position 0 S Frs S F 1 Krs M rs 14 Accumulator 1 0 Accumulator 1 0 Krs 24 Jump to 2 If Last Cale Was Negative TRUE Start Cut Segment Accumulator 10 SFes 18 SF 28 Accumulator 10 Wait for Cut Segment to pass Accumulator 10 Target Position 0 Accumulator 1 0 Accumulator 1 0 Kepr 13 Jump to 2 If Last Cale Was Negative TRUE Modulo Knife Targ Kepr 13 Pos Kepr 13 Loop forever Jump to LOOP QuickSilver Controls Inc Page 13 of 14 Application Note QCI AN034 QuickSilver Controls Inc Other Considerations Programmable Limit Switch PLS A PLS could be used to signal End of Cut to allow an outfeed stage to process the newly cut piece The PLS would be added to the knife program and configured to trigger sometime after the Knife Cut Segment Kcs See Application Note QCI ANO50 Programmable Limit Switch for details Control Constants In an Electronic Gearing application the slave has to determine its target position from incoming master enc
12. he controller s I O 6 and 7 See Application Note QCI ANO19 Electronic Gearing for more information It is assumed the master encoder rotates in the positive direction Reverse the A B signals to reverse your master encoder QuickSilver Controls Inc Page 5 of 14 Application Note QCI AN034 QuickSilver Controls Inc Servo Rotary Knife Simple Fixed qcp Positive Requires a Rotation e QuickControl 4 64 e SilverDust Firmware 37 Knife The following is an overview of Rotary Knife Simple Fixed qcp This QCP is well documented and should be easy to follow The following overview in combination with the rest of this app note and the QCP s source code remarks should allow the user to modify the QCP for their specific needs This program file is composed of the following programs Init Initialize application specific and derived parameters registers and setup the servo for an electronic gearing application On completion Init runs the Home to Index program The only registers you should have to edit for your application are Kcpr SFcs and Mn Home to Index Homes the servo to its internal index pulse Note how electronic gearing is used to rotate the knife at the Cut Segment s matching speed This ensures the knife will not bind during the homing process Once the index is found the encoder is zeroed to the index location and the Rotary Knife program is run QuickSilver Controls Inc Page 6 of 14 Application Not
13. o Index Same as Rotary Knife Simple Fixed qcp except e Thread 2 Queue Mn is started after index found see below for details Rotary Knife This program is similar to the same program in Rotary Knife Simple Dynamic qcp except that Mn is retrieved popped from the queue Q see below for details on Q If Q is empty SF is set to zero to stop the knife and we jump back to the start Once a valid Mn is received the EGM command is used the same as Rotary Knife Simple Dynamic qcp Note the first Mn after an empty Q causes the knife to start from a stop The EGM first ramps up to speed using AF and SF and then executes the Trap Move to move the knife to the correct place for the cut You will see the knife start up quickly as it ramps up to speed and then slow down as the Trap Move is executed This is normal QuickSilver Controls Inc Page 11 of 14 Command Add user specific code here Pop Mn from Queue Mn Q 50 Tail gt Mn 19 Hold motion if Q empty This is done by setting SF 0 Jump to VALID MN If Last Calc Was Zero TRUE Write 0 to SF 41 Register Loop back Jump to LOOP Valid Mn popped from Q Master Return Segment Mrs Mrs Mn Mes Mrs 23 Mn 19 Mcs 25 Knife Return Segment Geared Krsg Distance Knife will move during Mrs due to GR Krsg Mrs GR Krsg Mrs SFes 10 000 000 T64L 38 U64 Mrs 23 SFes 18 Krsg 30 T64L 38 U64 1 0000000 EGM Par
14. oder counts Because there is no pre planed trajectory to follow the servo loop does not have acceleration feedforward information This is less of an issue as the line is typically brought up to speed slowly low acceleration The various Step and Direction routines estimate velocity feedforward from incoming master encoder counts CTC CTC start with factory defaults and make the following change Ki 0 for increased stability Increase Ki if your application requires the servo to firmly hold its position while stopped NOTE Kv2 may need to be increased for larger inertial mismatches 10 See Technical Document QCI TD054 Servo Tuning Missing Register Marks Rotary Knife Registration qcp assumes the products can change length Mn often It cannot therefore distinguish between a missing registration mark and an extra long product If your application only has only small changes in Mn a missing mark can be identified and Mn for the missing mark can be calculated using the past Mn s QuickSilver Controls Inc Page 14 of 14
15. peed By default Mmin is Mmin Mcs Mmin lt Mmax Mmin lt user defined gt Material Length Mn Mn is automatically calculated by reading the difference between two registration marks NOTE Because the difference between two readings is being used to calculate Mn the RMS delay or de bounce time is cancelled out Therefore a high speed RMS is not required NOTE The 2 s complement math makes the equation work even through master encoder rollover QuickSilver Controls Inc Page 9 of 14 Application Note QCI AN034 Quicksilver Controls Inc Setup 1 Do Simple version steps 1 3 2 Wire RMS to I O 1 with an HIGH meaning registration mark detected The only place this input is used is in the WBE command at the beginning of T2 Queue Mn Modify this WBE command if your RMS is not active HIGH on I O 1 3 Edit the Application Specific Parameters section of the Rotary Knife Registration qcp Init program Edit the registers using information from your application QuickSilver Controls Inc Page 10 of 14 Application Note QCI AN034 QuickSilver Controls Inc Rotary Knife Registration qcp The following is an overview of the Rotary Knife Registration qcp file This program file is composed of the following programs Init Same as Rotary Knife Simple Fixed qcp except e Moved Mn and Mrs to Rotary Knife program e Added Mnmax Mnmin which defines the longest and shortest material lengths Home t
16. r 13 Loop forever Jump to LOOP QuickSilver Controls Inc Page 8 of 14 Application Note QCI AN034 QuickSilver Controls Inc Rotary Knife Registration Requires Direction of e QuickControl 4 64 Rotation nife e SilverDust Firmware 37 gf Material Feed cat This version of the Rotary Knife uses a sensor RMS to read registration marks on the material to calculate the Material Length Mn Since there A Master could be several registration marks Encoder between the knife and the RMS the program needs to queue up several lengths Registration Marks Registration Mark Sensor RMS In the case where the RMS stops detecting registration marks i e material is not present the knife comes to a stop after the Cut Segment Once a mark is read the knife starts back up again to get into position for the next cut Knife Return Additional Application Specific Segment Krs Parameters E T e Maximum Material Length in Seament Kes Master Encoder Counts Mmax Mmax is also the distance from ZN i i J l Mcs the RMS to end of Mcs i i l RMS i i lt gt Mrs 1 Mn 2 1Mn 1 Mn i lt gt lt a Mmax SS Mmax lt user defined gt e Minimum Material Length Mmin You may change Mmin to an Application Specific Parameter if you have a particular Mmin you want to enforce The smaller Mmin the faster the knife axis will have to go Be careful not to exceed the knife s maximum s
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