Hi All

I am trying to get my MX3660 to control spindle speed by PWM on Linux cnc. I was expecting to put in a voltage and get out between 0v and reference voltage -1.1v but this isn't happening. I tried it on my mill and it didn't work so I used a 9v battery and my multimeter to see what is going on.

so +ve 9v goes into the 10v plug on the MX3660. the 0-10v 'wiper' out put is connected to the positive probe on the multi meter. Then the negative probe on the multi meter is touching the negative battery terminal.

With linuxcnc set to spindle off the voltage recorded is 7.5v and as I increase the spindle speed rate it goes up to 7.75v.

I was expecting it to have a starting point of 0v otherwise the spindle will always be on. Has anyone ever faced this issue or have any ideas why it would be happening?

Jools