A stepper motor attached to PCI-7334 travels in same direction for both +/- input

[MrSteve]

Hi everyone, I'm seeing some bizarre behavior on my system and was hoping you could help me out.

I have the PCI-7334 stepper controller installed and running on my system, with 2 axis-s connected.

Axis 1 operates as expected, running one direction for a positive target, and the other for a negative target.

Axis 2 on the other hand, runs in the same direction regardless of if I give it a positive or negaative target position.

This seems to be  limited to axis 2, I connected the wires running from axis 1 on the connector block to the second motor driver and it then started to act as expected.

Any idea whats going on?

[Jochen]

Have you checked with a DMM or a scope if the Dir output is working fine? Maybe this behavior is caused by the wiring of the open collector outputs for step & direction. Maybe due to device tolerances the current driven by axis 2 for the Dir output is a little bit too low, so the drive doesn't recognize the changed level. Please refer to this link in our KB and check if the wiring hints apply to your setup.

A second option is a defective board. In this case please contact your local NI branch.

Thanks,

Jochen