The 0-10V signal is unacceptably dirty when inspecting it with an oscilloscope, and the spindle speed fluctuates here and there. The signal is generated from a PWM signal so dirty is what can be expected. The fluctuation one sees depends on the capacitance of ones VFD input and using a shielded cable will not remove this fluctuation. I’m now using a 33uF capacitor between GNDi and the voltage output and that smoothens things considerably. (The capacitor value is not calculated in any way, just a pick from my capacitors bin.)

I find no explanation from the manuals for the ‘PWM module period’ and ‘Multiplier’ value adjustments. I’m now using Multiplier value of 0.004129 and that gives me a pretty linear output for the default PWM module period value 100us. Changing the PWM module period would change everything again. If the manufacturer hears me or if someone knows, what are the manufacturers instrutions to get a decent output for the spindle speed?