pulse width with stepper 7342?

[Giana Nicolini]

I'm controlling two stepper motors with a NI-7342. I distribute the signals via an UMI-7774 powered with 24V. Viso and Ciso are, at the moment, the same 24V of the main supply.
I do not use feedback. With MAX I've configured the interface and I can see the step & dir waveform on the scope.
Unfortunately, the step pulse is only 15us wide and the motor driver does not see it.

Q.: Is there a way to increase the pulse width?

Thanks in advance

G.

[Jochen]

The NI-7342 (as any other NI-Motion board) doesn't allow to set the pulse width of the step output as an absolute value. Still you can vary the duty cycle of this signal between 25% and 50% by using flex_setu32() in C or Set u32.flx in LabVIEW. Please refer to the NI-Motion Function Help or the NI-Motion VI Help. The attribute that you need to change is Step Output Duty Cycle.

I hope this helps,

Jochen Klier
National Instruments

Message Edited by Jochen on 09-13-2007 04:17 PM

[Giana Nicolini]

Everything ok, thanks alot.

G.

[Hermes Arytto]

I´m in a similar trouble. But I´m using a NI-7340 to control a stepper motor. I tried to change the duty cycle using Set u32.flx in LabVIEW but I didn´t see changes in pulses on the scope. To certify that Set u32.flx was working I used this tool in an example Simple One Move.vi and I didn´t see changes again.

How can I increase the pulse?

Thanks.