How can I do position maintenance using a digital input to capture an encoder count and adjust the move profile on the fly.

[Boette1]

I have a rotary table (45:1 ratio) being driven by a stepper motor. I am using a 7344 motion controller. I want to be able to do position maintenance on the move. I have a home input on the table. My thoughts were to capture the position when the table goes by the home input and compare it with the previous time and make the adjustment in the next move. I am just not sure what the best way to do this is. I am thinking that I want to tie the home input to one of the trigger inputs as well as the home.

[Andy_Bell]

Hello,

Your best option will be to use an encoder for feedback in your system. If you use an encoder then at the end of the move, the controller will compare your trajectory position with the position the encoder reads (the actual position) and make the necessary adjustments. Also, this is all handled transparently so you won't have to worry about any complicated programming issues.

Regards,
Andy Bell
Applications Engineer
National Instruments