Is it the lenze controller or the isolation board on the end of the lenze ie the board on the opposite end to the rotary trimmers for setting max min appends etc

If it is the isolation board on the end then as long as you can isolate the BOB from the lenze itself then you don’t need the isolation board
Beware the lenze input control voltage floats at 112v to 122v depending on the commander spindle speed (assuming 220volts AC mains voltage)
I used a diycnc board to take step/ dir from the BOB and convert to pwm 0 to 10 volts as it also provides isolation for the BOB

You can connect a potentiometer 4.7k ohms or there about to test the lenze controller. Wiring schematic for the lenze 540 is on google and easily found

Cheers. Paul


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