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Testing rig for stepper drivers?

Posted by jemenake 
Testing rig for stepper drivers?
March 18, 2018 01:38PM
Executive summary: Does someone sell (or offer schematics for) a device to test/adjust stepper drivers?

I’ve got several that I suspect are defective, because, when I plug them into my 2-in-1 Arduino/RAMPS board, the light (which is normally always-in) comes on for a second or two and goes out. It scares the heck out of me because I’ve already fried two Arduinos and on 2-in-1, so I don’t dare leave the driver plugged in and the controller board powered while it take a bunch of voltage readings and experiment with different pot settings.

“Wouldn’t it be great,” I asked myself, “if there were a little circuit board I could plug my driver into and it would tell me if the driver were behaving normally (eg. not drawing too much current, producing proper output on steps. etc), so that I would know to toss it and not try to get it to work in my RAMPS board?”

In fact, wouldn’t it *also* be great if I could use it to adjust my Vref in a way that weren’t so prone to shorting the Vref pin like when you do it on the actual, powered RAMPS board (like how I fried one of my Arduinos)?

It would probably be greater *still* if, instead of just relying on ballpark values for Vref, the circuit could try to drive one of the steppers on the printer at certain acceleration rates, back and forth. I could leave it running at a certain Vref setting for, say, 10 minutes, and I could see if the stepper motor got too hot or if it was skipping (determined by whether extruder was drifting away from the two points it had started out moving between).

Does anybody make one of these? Or have a schematic/code for one?
Re: Testing rig for stepper drivers?
March 18, 2018 03:24PM
How about Ramps_test? It's a program for Ramps/Mega to test mainly the RAMPS functions, but runs continusly for driver testing too.
I'd start with no load and when you found out, how the steppers react, you can integrate it in your printer. But it doesn't care about jerk, acceleration or steps/mm.
open | download - _Ramps_test.ino (3.2 KB)
Re: Testing rig for stepper drivers?
June 27, 2018 07:09PM
Something like this?

Easy Stepper on RepRap.me

Wiki Article on it: Easy Stepper Wiki

It doesn't give you the feedback you're looking for, but it does allow you to test driver/motor combinations and adjust the VRef. Was actually considering getting one myself.
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