I'm using a gecko g540 to control a hitachi WJ200 vfd. I'm using the 0-10v signal for speed and output 1 for run control. Everything was working fine but today I came down to machine some parts and unplugged a USB cable connecting the hitachi to the compute, just because i didn't think it necessaryr. When I went to run my program, the spindle didn't start up and I almost wrecked a bit.

I figured it t on accident when I started up pro drive next, hitachi's programming software to see if any settings mysteriously changed on me. When I plugged the USB cable back in, the spindle started up!

I'm thinking this must be a grounding issue because there's no control software running on the pc to run the vfd.

My connections between the gecko are

GND, 10v and signal to pins L, H and O, Output one to smart pin 1.

Any ideas as to what may be wrong?