After a bit of a late night, I've connect four motors to my servo controller. I wanted to clean up the layout a little, and I think for a prototype, it's pretty neat.

I had recently finished fitting encoders to my other motors, and thought it was time to test the limits of the controller.

I had always designed my controller to handle four servos, but didn't have the hardware to test it. Armed with the extra hardware, I had the opportunity to see how well my theory would work in practise. Once again, I was very happy with myself.

There's a couple of things the keen-eyed will notice.

• The motors don't always turn at the same speed - The test here is limited by the power delivered to the motors. It's set to output 33% max. Different motors will have slightly different performance, especially when moving in different directions. The motors I'm using slightly prefer one direction to the other.
• The motors overshoot - the PID parameters aren't tuned yet.
• The motors sometimes hunt - it's the cogging of the unloaded motor & the PID parameters aren't tuned yet.

This test was just sending serial set-point commands. The controller can also be able to decode STEP+DIR input from Mach3 and such (I haven't fully wired up the break out board yet).

I've put it off long enough, I think I'll have to work on the PID tuning...