Can I add clamping diodes to the outputs of the MID-7602?

[EM]

I am driving a stepper motor with the MID-7602 and experiencing some noise problems on some sensor signals. The noise appears to be generated by the 20kHz switching of the MID-7602. The motor output voltage of the MID-7602 is 30V.

Can I add clamping diodes (12V Zener) to the motor outputs to reduce the generated noise?

What impact would this have on motor performance? (I am testing a product that is normally driven by a 12V stepper driver.)

[algames]

Before trying a solution with a diode, I would like to suggest the following options that might help to reduce or remove the noise.

Have you trying shielding your cables?
Make sure that the motor signals are in a different cable that any sesnore or switching signals cause niose might come from them.

Where are the sensors with relationship to the motors? If they are very near you might try getting them away from the motors.

Are you connecting the sensors to the analgo inputs of the motion controller? If so, then you could try to condition your signals either by placing a lowpass filter on them or you might even consider using some of our signal conditioning solutions (SCXI).

What is the frequency of the noise you are seeing? If you are reading high fre
quency signals with high freuency noise a filter might not work.

Let me know what you think

[EM]

Thanks for the reply. My application is a production line tester for an existing assembly.

Unfortunately, the assembly has several problems from a noise aspect. First, the sensors are within 3 inches of the motor. Second, inside the assembly the motor signals are in a flex cable which is taped back-to-back to the signal flex cable. The coupling between these cables appears to be quite high.

I am using shielded cable for the motor signals inside the fixture. It appears to help the problem slightly, but not significantly enough.

The sensors are connected to comparators in the test fixture, before sending the signals to the motion controller. The signal is a 5V pulse train, with a maximum frequency of about 250Hz. The noise is 20kHz. I am still expe
rimenting with filtering, but can't afford to change the rise time of the signal.

If the filtering doesn't quite clean things up enough, can the output voltage of the stepper amp either be adjusted or clamped? I certainly would like to avoid this solution, but if necessary can it be done?

[PdB]

If you have enough unused signal cables, you can consider to take a driver and an inverted driver (electronics) that you connect to the comperator output.
At the receiving end, connect the input of an optocoupler between the leads (with some aiding 3-rd order passive filtering) for extra protection.
Note: this will only work if the signal from the comperator is clean.