Using a Non-7390 Motion Controller with a P-Command Drive Primary Software: Driver Software>>NI-Motion/FlexMotionPrimary Software Version: 7.0 Primary Software Fixed Version: N/A Secondary Software: N/A Hardware: Motion Control>>Controllers
Problem: I have my 7330/7340/7350 motion controller configured in MAX in closed loop stepper mode and it is connected to a p-command drive. Every time I do a move, the encoder feedback always shows that the motor is a few counts off. Solution: When using a 7330/7340/7350 motion controller with a p-command drive, you should not use it in closed loop stepper mode. In closed loop stepper mode, the motion controller will execute pull-in moves at the end of a move if the encoder feedback is off from the target position. However, a p-command drive receives a number of pulses and then uses its own PID control to move the motor with an analog voltage output, so a p-command drive does not need pull-in moves. Instead the pull-in moves are now sending extra pulses and incorrectly changing the p-command drive’s target position. When using a 7330/7340/7350 motion controller with a p-command drive, you should select Stepper for Type in the Axis Configuration tab in MAX, and then select P-Command instead of “closed loop” for Stepper Loop Mode in the Stepper Settings tab. Related Links: Attachments: 
Report Date: 10/18/2006 Last Updated: 10/30/2007 Document ID: 42HHJIS4 |
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