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5I25 of course. duh

Now I can find info about it in the emc2 manuals more easely

Ok, I will contact the local distributor to buy one. My step drivers are capable of x64 microstepping so the high step rate can indeed be nice.

Thanks, have a nice day

Jacques

Just in case you might be interested, I finally managed to track down my problem by probing the driver circuit with a scope. As you suspected, my parport is a bit weak on voltage. My stepper drivers are optoisolated and the leds are just too starved current wise to turn on most of the time.

On these drivers, the 5 volt input is set up to go through a 680 Ohm resistance so as to limit the current trough the led. I simply replaced that resistance with a 370 Ohm resistance and now, I get reliable stepping in both direction. I will see if the 50 Khz max steeping rate is ok for my current setup and if not, I will go definately go the 5I25 route.

Regards

Jacques