control a stepper motor using SAA 1042 and PWM

[sushma]

Hi ......I am trying to control the speed of bipolar stepper motor(STH-56D101) using the Motorola SAA1042 driver and the technique being used is PWM.The VI we are generating is not giving us the PWM wave we need instead its generating a square wave and thus we see no movement in the motor.Plz help me i have been stuck at this point for more than a week .............

[AnalogKid2DigitalMan]

Have you set the duty cycle to something other than 0.5 prior to running the vi? 0.5 will generate a square wave with 50% duty cycle.

The way this vi is written will not allow you to change duty cycle while the program is running.

Duplicate postings:
http://forums.ni.com/ni/board/message?board.id=240&message.id=3994

Message Edited by AnalogKid2DigitalMan on 11-08-2006 07:58 AM

http://forums.ni.com/ni/board/message?board.id=170&message.id=214290#M214290

Message Edited by AnalogKid2DigitalMan on 11-08-2006 07:58 AM

[VuD]

Sushma,

There are also some examples in LabVIEW which will give you a better idea of how to set up PWM.  If you have NI-Motion, there are specific flx functions that you can use to configure PWM for motion control (i.e. PWM duty, Configure PWM, etc.).  Hope that helps.

Regards,
Vu D
Applications Engineer

[sushma]

Ya i have tried changing the duty cycle and it works too.......................