Configuring Feedback and "Load Target" VI's

[RWA]

I have configured an axis to accept the signal from the DAC as primary feedback.  Next, I wish to be able to "load a target" into the program somehow so that the stepper motor will move until it is within some deadband of the desired digital bit signal (converted from load). 

I tried the "Load Target Position" VI, but this appears to still be loading steps.  Is this method correct, or is there another method by which to do this?

Message Edited by RWA on 07-08-2005 04:19 PM

[Jochen]

Yes, this method is also correct with analog feedback. Please refer to the document that I have posted for you in this thread.
As a bottom line: 12bit ADCs provide a travel range from -2048 to 2047 steps (NI 734x and NI 733x motion controllers), 16 bit ADCs provide a travel range from -32768 to 32767 (NI 735x motion controllers).

Best regards,

Jochen Klier
National Instruments Germany

[RWA]

When I try the analog method and try to configure the feedback, I get an error message along the lines:

"Cannot configure feedback to enabled axis"

So, I disabled the axis, configured it, then re-enabled the axis...then something like "Axis disabled, cannot complete move" came up.

Also,

Using the analog feedback doesn't return displacement (vertical) how do I get it to do that?  I've referred to the attatched document many times and I feel as though it assumes that I am more familiar with the setup than I am currently.

Help!

[Jochen]

This sounds like you have tried to change the feedback source while a move was running. You need to stop the axis in order to change the feedback. I tried the following sequence and it worked for me:

1. Stop axis
2. Disable axis
3. Change feedback to analog
4. Enable axis

For the case you still get an error please provide the exact error number.

Jochen