-10V to 10v circuit

[Jonathan]

Assuming the OP still wants -10 to +10.
With the method proposed previously by Jonathan there exists a problem, if the reference wire to the servo driver goes open circuit, the drive would go to full speed reverse.

My intention was to expand on the circuit design when if it turned out to be necessary. There's a much easier way to solve that problem, but I don't think it's worth discussing the circuit here.

[irving2008]

My intention was to expand on the circuit design when if it turned out to be necessary. There's a much easier way to solve that problem, but I don't think it's worth discussing the circuit here.

Agreed, and I don't think OP wants to use analogue mode anyway as AFAIK Mach3 doesn't support open-loop servo & encoder feedback for positioning.

[EddyCurrent]

My intention was to expand on the circuit design when if it turned out to be necessary. There's a much easier way to solve that problem, but I don't think it's worth discussing the circuit here.

Oh yes there is, what's the point of keeping it a secret ? I want to hear about it.