BrianSS

The move that this axis makes is not always the same. Sometimes it is a 6 inch move, other times it only needs to move a few inches. I have seen it stop at seemingly random spots during the moves. I believe the axis is tuned fairly well and I am not seeing any significant following error. The only thing I can see is that when it stops I have the Block request bit on this axis. One of the moves it made was a move from 21.4" to 20", and it stopped ~20.75". The "rest" position for this axis is 21.5", so when we took it out of automatic (all axis' go to "rest" position) and the move command was re-issued, it succesfully moved from 21.5" to 20". So, by changing the start point by 0.1", the axis got to it's desired position.

Here is PROG 1 (called from PROG 31 above): ; Variables to pass arguments to subroutine ; Note that the variable numbers here are fixed #define AArg Q101 ; Variable to pass A argument #define DArg Q104 ; Variable to pass D argument #define PArg Q116 ; Variable to pass P argument #define SArg Q119 ; Variable to pass S argument #define VArg Q122 ; Variable to pass V argument #define XArg Q124 ; Variable to pass X argument ; Variables for general-purpose use #define ProgDist Q150 ; Signed distance for move #define Dir Q151 ; Direction of move #define AccDist Q152 ; Mag of distance for accel #define DecDist Q153 ; Mag of distance for decel #define AccTime Q154 ; Total time for accel #define DecTime Q155 ; Total time for S decel #define AccSTime Q156 ; Time for half of S accel #define DecSTime Q157 ; Time for half of S decel #define Apeak Q158 ; Mag of top accel reached #define Dpeak Q159 ; Mag of top decel reached #define ApeakTime Q160 ; Time at top accel reached #define DpeakTime Q161 ; Time at top decel reached #define ReachSpeed Q162 ; True (1) if move hits prog speed #define Seg1Dist Q163 ; Signed distance of 1st seg #define Seg1EndVel Q164 ; Signed end vel of 1st seg #define Seg2Dist Q165 ; Signed distance of 2nd seg #define Seg2EndVel Q166 ; Signed end vel of 2nd seg #define Seg3Dist Q167 ; Signed distance of 3rd seg #define Seg3EndVel Q168 ; Signed end vel of 3rd seg #define Seg4Dist Q169 ; Signed distance of 4th seg #define Seg4EndVel Q170 ; Signed end vel of 4th seg #define Seg5Dist Q171 ; Signed distance of 5th seg #define Seg5EndVel Q172 ; Signed end vel of 5th seg #define Seg6Dist Q173 ; Signed distance of 6th seg #define Seg6EndVel Q174 ; Signed end vel of 6th seg #define Seg7Dist Q175 ; Signed distance of 7th seg #define TopVTime Q176 ; Time at top speed #define Vpeak Q177 ; Peak speed if less than prog #define OldAbsIncMode Q178 ; Saved to restore at end #define FourSecDist Q179 ; Distance in 4 sec at top speed ; Subroutine used by multiple other programs to execute move using PVT segments OPEN PROG 1 CLEAR READ(X,S,V,A,D,P) ProgDist=XArg-SArg ; End minus Start, signed qty Dir=ABS(ProgDist)/ProgDist ; +1 or -1 (0 if no distance) ; Make sure S-curve percentage is in proper range IF(PArg<0.04) PArg=0.04 ; Minimum 4% S-curve IF(PArg>0.96) PArg=0.96 ; Maximum 96% S-curve ; LIMITS ACCEL RATE SO THAT EACH ACCEL SLICE DOES NOT EXCEED 4000 ms IF (((VArg/AArg)*1000*PArg/2)>4000) ; Calculates S-Curve AccTime AArg=VArg*1000*PArg/(4000*2) ENDIF IF (((VArg/AArg)*1000*(1-PArg))>4000) ; Calculates Linear AccTime AArg=VArg*1000*(1-PArg)/4000 ENDIF ; LIMITS DECEL RATE SO THAT EACH DECEL SLICE DOES NOT EXCEED 4000 ms IF (((VArg/DArg)*1000*PArg/2)>4000) ; Calculates S-Curve DecTime DArg=VArg*1000*PArg/(4000*2) ENDIF IF (((VArg/DArg)*1000*(1-PArg))>4000) ; Calculates Linear DecTime DArg=VArg*1000*(1-PArg)/4000 ENDIF ; Compute distances needed to get to and from full speed AccDist=VArg*VArg/AArg/2 ; Dist mag to reach full speed DecDist=VArg*VArg/DArg/2 ; Dist mag to decel to zero IF(AccDist+DecDist Vpeak=VArg ; Top speed is programmed ReachSpeed=1 ; Flag for future logic ELSE ; No full-speed segment Vpeak=SQRT(ABS(ProgDist)/((1/AArg+1/DArg)/2)) ; Lower peak speed mag AccDist=Vpeak*Vpeak/AArg/2 ; Dist mag to reach peak speed DecDist=Vpeak*Vpeak/DArg/2 ; Dist mag to decel to zero ReachSpeed=0 ; Flag for future logic ENDIF AccTime=Vpeak/AArg ; Total accel time in sec AccSTime=AccTime*PArg/2 ; In each half of S, in sec ApeakTime=AccTime*(1-PArg) ; Time at peak accel, in sec Apeak=Vpeak/(AccTime-AccSTime) ; Magnitude of peak accel Seg1EndVel=Dir*Apeak*AccSTime/2 ; Segment 1 signed end velocity Seg1Dist=Dir*Apeak*AccSTime*AccSTime/6 ; Segment 1 signed distance Seg2EndVel=Seg1EndVel+Dir*Apeak*ApeakTime ; Seg 2 signed end velocity Seg2Dist=(Seg1EndVel+Seg2EndVel)*ApeakTime/2 ; Seg 2 signed distance Seg3EndVel=Dir*Vpeak ; Segment 3 signed end velocity Seg3Dist=Dir*AccDist-Seg1Dist-Seg2Dist ; Segment 3 signed distance IF(ReachSpeed=1) ; Segment at programmed speed? Seg4Dist=ProgDist-Dir*(AccDist+DecDist) ; Signed distance at speed Seg4EndVel=Dir*Vpeak ; Signed end velocity TopVTime=Seg4Dist/Seg4EndVel ; Total time at top speed, in sec ENDIF DecTime=Vpeak/DArg ; Total decel time in sec DecSTime=DecTime*PArg/2 ; In each half of S, in sec DpeakTime=DecTime*(1-PArg) ; Time at peak decel, in sec Dpeak=Vpeak/(DecTime-DecSTime) ; Magnitude of peak decel Seg7Dist=Dir*Dpeak*DecSTime*DecSTime/6 ; Segment 7 signed distance Seg6EndVel=Dir*Dpeak*DecSTime/2 ; Segment 6 signed end vel Seg5EndVel=Seg6EndVel+Dir*Dpeak*DpeakTime ; Segment 5 signed end vel Seg6Dist=(Seg5EndVel+Seg6EndVel)*DpeakTime/2 ; Seg 6 signed distance Seg5Dist=Dir*DecDist-Seg6Dist-Seg7Dist ; Segment 5 signed distance BLOCKSTART ; Beginning of step sequence INC(X) ; Specify X moves by distance PVT(AccSTime*1000) ; Set move mode and time in msec X(Seg1Dist):(Seg1EndVel) ; 1st half of S-curve accel PVT(ApeakTime*1000) ; Time at peak accel in msec X(Seg2Dist):(Seg2EndVel) ; Peak accel segment PVT(AccSTime*1000) ; Time in 2nd half of S-curve X(Seg3Dist):(Seg3EndVel) ; Segment to reach top speed IF(ReachSpeed=1) ; Segment at programmed speed? WHILE(TopVTime>4) ; Too long for 1 PVT move FourSecDist=Seg4EndVel*4 ; Distance in 4 sec at top speed PVT4000 ; Set 4-sec move X(FourSecDist):(Seg4EndVel) ; Constant speed move for 4 sec TopVTime=TopVTime-4 ; Time remaining at top speed Seg4Dist=Seg4Dist-FourSecDist ; Distance remaining at top speed ENDWHILE IF(TopVTime>.0011) ; If Seg4 Move time is > 1.1 msec PVT(TopVTime*1000) ; (Remaining) time at top speed X(Seg4Dist):(Seg4EndVel) ; (Remaining) top-speed segment ELSE Seg5Dist=Seg5Dist+Seg4Dist ; Add skipped Seg4Dist to Seg5Dist ENDIF ENDIF PVT(DecSTime*1000) ; Time in 1st half of decel S-curve X(Seg5Dist):(Seg5EndVel) ; 1st half of S-curve decel PVT(DpeakTime*1000) ; Time at peak decel X(Seg6Dist):(Seg6EndVel) ; Peak decel segment PVT(DecSTime*1000) ; Time in 2nd half of decel S-curve X(Seg7Dist):0 BLOCKSTOP RETURN CLOSE

Hello, I am currently running a PVT move using the following program: OPEN PROG 31 CLEAR P7030=((M345*P7433*P4036)+((M362/(I308*32))/M391)) P3361=P7030 P3360=1 P3341=P4430 P3340=1 DWELL(0) IF(P7030-0.01 IF(P4430 P7630=6 GOTO1 END IF END IF DWELL(0) DWELL(0) CALL1 X(P4430)S(P7030)V(P4434)A(P4436)D(P4438)P(0.73) N1 DWELL(0) CLOSE The motion variables are all being sent from the PLC. Occasionally the axis will start the move and not get to the desired position and X:$B0 Bit 11 Block Request will be on. I have taken I5313 up to 10, this did not seem to help. The moves are typically a few inches for this axis and I have seen it on numerous different moves.