Parker ViX250IM, User Manual

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VIX IM MICROSTEPPER INDEXER DRIVE USER GUIDE 90
Settle Time
When Position Maintenance is enabled all moves will track actual position against
commanded position. Position Maintenance allows the in-position signal to be held off for a
settle-time, the value of which can be programmed in the command parameters.
Speed Of Correction
Once a move has been completed and the controller decides position maintenance
correction is required, it will move the motor at a fixed speed of 1rps.
Example of Position Maintenance
The following code illustrates how position maintenance is implemented. The example is
based upon a motor resolution of 4000 steps per rev and a 1000 line encoder giving 4000
counts per rev.
1DECLARE(TRIAL)
1MOTOR(X,X,4000,X,X,X,X)
;X is set depending upon the application
1TRIAL:
1ON
1R(EI)
; check encoder is set to quadrature operation
1POSMAIN0(20,3,0) ; set-up position maintenance, dead band of 20 encoder
steps, output 3 to be used, no programmed settle time
1D40000 ; program distance, 10 revs
1V5 ; set velocity to 5 rev/s
1A10 ; set acceleration to 10 rev/s/s
1POSMAIN1 ; enable position maintenance
1POSMAIN ; check status of command
1W(PA,0) ; set absolute position to zero
1G ; start the move, motor turns 10 revs
1R(PA) ; read position
1END
Following the G command the system will attempt to correct any final position error at the
end of the move.
Note: When the command is armed output 3 will come on with the motor in position and
stationary. When the G command is given output 3 will turn off until the motor is back in
position within the dead band.