Connecting IO to 24V PNP PLC outputs

[Glen_Remix]

Hi all,

I'm working on a project using a Duet3 6XD for motion control for a larger system controlled by a PLC.

The PLC has 5 24V PNP outputs which trigger macros on the Duet, and 2 inputs from the Duet to indicate 'Busy' and 'Finished' states.

I have used up all four opto-isolated IO, and need to use three other pins.

The datasheet states that the Input pins are +30V tolerant. Does this mean that I can connect the IO GND pin to the PLC 0V and the ioX.in pin to the PLC Output? Does this require anything else to avoid damaging the Duet?

The PLC output is up to 0.5A per channel.

Any advice would be greatly appreciated.

Thanks,
Glen

[dc42]

@Glen_Remix said in Connecting IO to 24V PNP PLC outputs:

The datasheet states that the Input pins are +30V tolerant. Does this mean that I can connect the IO GND pin to the PLC 0V and the ioX.in pin to the PLC Output?

No because the input needs to be pulled down in order to register a logic low. However, you can use two resistors to connect a PNP output to a Duet input. See https://docs.duet3d.com/en/User_manual/Connecting_hardware/Z_probe_connecting#pnp-output-normally-open-inductive-or-capacitive-sensor.

[Glen_Remix]

@dc42 Thanks for your quick response.

I understand, thanks for clarifying. I think I will use interface relays.

Cheers.