motion control

[GT]

"I have a 7344 board with the UMI7764 which worked fine to control a brush-type motor. I now have a brushLESS motor (requiring commutation via Halls). Am I able to use the 7344 and UMI7764 to control this motor?"

[Jochen]

As long as your drive does the electronic commutation for your brushless motor you will be able to usee the 7344 and the 7764.
Typically these types of drives generate a quadrature encoder emulation signal. In this case for the 7344 there is no major difference between a brush-type and a brushless motor.

Things are different if your drive is not capable of doing the commutation. In this case you should exchange the 7344 to one of the newly released 735x series motion control boards which are pin- and software-compatible to the 734x boards. These boards can do the electronic commutation onboard. In electronic commutation mode the 735x boards use two axes outputs for each axis that needs electronic commutation. That means with the 7352 you can control one, with the
7354 two brushless motors. For more information please refer to this link:
http://sine.ni.com/apps/we/nioc.vp?cid=10026〈=US

Best regards,

Jochen Klier
NI-Germany

[GT]

Thanks Jochen. I have a copleycontrol accelus digital servo amp which is capable of this. Thus, the halls inputed directly into the drive. However, when I close the position loop (encoder) via the 7764 and the motor is enabled, the motor seems to be getting full current (as the shaft can't be rotated). Nor am I able to jog the motor using the MAX. Any suggestions?

[Jochen]

I haven't worked with this special type of servo amp so far but with many others. There could be several reasons for the behvior you could check:

1. Have you specified the correct control input for your amp? Many amps provide various control inputs like Analog Input (that's what you need) and several fieldbus options

2. If you have configured your amp for velocity mode you should be able to move the motor by applying a DC voltage to the analog control input.

3. Please check the status of your 7344 in the Interactive window in MAX. Are any limit switches active? Is the motor stopped because a following error has occurred?
In these cases you may have to change the polarity of the limit switches and/or of the encoder or in case of the followi
ng error you may need to adjust your PID settings.

Jochen
NI-Germany