I'm not thrilled about having the vfd & Bob AI/AVI, CM/ACM connected together without a working voltage reading from the bob first.
I ALWAYS leave the bob analog output not connected until I know the volt readings are correct using the voltmeter.
By now myself I would be frustrated and ONLY connect a good 10v/CM from vfd to the corresponding 10v/GND on the bob as a test.
Leave all other vfd connections off. Stick voltmeter on AVI/ACM and test if it gives voltages on speed changes.
If no good still, play with changes to PWMbasefreq in Mach.
That's 10v/CM > 10V/GND ONLY. Nothing else until analog out reads good.
I'm NOT condoning to do this AT ALL.