For the printer I am working on I need to run the Y and Z axis with two external stepper drivers each, but this is not going well so far. Currently the external driver for my X axis is working fine and I've yet to test the extruders, but they will be NEMA 17s running off the on board drivers so I have not reason to think they won't work.
Y and Z are wired up the same. I have the signal wire going to one of the drivers, then daisy chained to the other driver. Each driver is wired up to their own stepper and getting their own power from a 24v 20a supply. When I run each in their respective negative direction, they move in sync as they should with normal sounds. When I run them in the positive direction they don't seem to move at all, maybe a little, but not much and they also make a grinding sort of sound like it's skipping steps.
I have also disconnected each extra driver so only a single driver was running off the signal from Smoothie and each driver operated normally with only 2 (1 Y & 1 Z) of the 4 connected, in any combination. I checked the signal current ratings for Smoothie and my drivers and came to the conclusion that I wasn't getting nearly enough current to run each driver from a single output.
So, first things first, am I missing something? Is there some basic "thing" that I missed that would swiftly solve my woes? If it is indeed more complicated than that, a friend of mine suggested using something to amplify the signal coming out of Smoothie to create enough current to drive the drivers. Would that be a way to go and is it possible with this board?
An idea I had was to see if there was a way to use the free GPIO pins to send signals to the two extra drivers and slave/mirror them with another axis. Would that be possible? My hope with this approach is that you'd have the ability to home each side of a gantry to ensure it's square to the X axis. Granted this is only really needed if you have a reallllllly long gantry like mine, which is why I need two steppers in the first place :)
Here is some info about my drivers and steppers to help the ball rolling on dissection. I'm running everything off 220v also in case that might be helpful lol
Steppers - openbuildspartstore /nema-23-stepper-motor
Drivers - amazon /SainSmart-Micro-Stepping-Stepper-Driver-Bi-polar
But in any case, any solution that works is a good solution in my book, I just want to get my printer going! Thank you for your time!