[Jocke76]

Hello!,

I'm retrofitting a TOS CNC mill with a Siemens Sinumerik 802C.

The original Heidenhain TNC 145 shortcircuited because a cabinet lamp had worn thorugh a flatcable in the DC reg. for the axis. (Simoreg 6RB2025)

Should I isolate the 0-10V, analog setpoint, signals between the 802C and the Simoregs?

The 802C can deliver 3mA on the 0-10V outputs, I haven't figured out the input impedance for the Simoreg 6RB2025 / 6RA2620 yet.

I've been looking at Phoenix Contacts 3-way isolator, but they have around a 3mS delay on a 10-90% rising edge (if I'm not wrong) and are quite expensive (DIN rail mounted)

If anyone has a schematic to a mill that uses the 802C and wants to share it I'd be happy to look at some examples!

Thanks!

//Jocke

[Al_The_Man]

Most drives that use analogue ±10vdc have op amp input so the impedance is high and should not present a problem.
Of all the different systems I have implemented and mixed and matched over the years I have never had a reason to isolate the ±10vdc analogue signal.
Al.

[Jocke76]

Ok!, then I won't isolate the ±10VDC signal!

I suppose you don't want to build in unnecessary delays in the system, and like you said, the Simoreg drives have op amp inputs, (6RB2025 have 10kΩ input impedance)

Thanks!