Rev Pi DI Reading of Active Low (0V) Signals

[ctf]

I have an existing system with a switch that provides a 0V (V-) reference when closed, otherwise it is disconnected/open. Is there any configuration of the Revolution Pi DI (or DIO) inputs that are able to read distinguish between these two states? I do not see any information regarding internal pull up/down resistors on the inputs, which could be useful in this scenario. The existing hardware was able to read these inputs successfully, but I am replacing that old hardware with Revolution Pi components. I wanted to ask before looking for alternate solution in case I am missing something in the documentation, etc. Thanks for the assistance.

[dirk]

Hi ctf, the device at the digital input (MAX31913) requires a current flow into the input pin. However, the TO requires an input with pull-up resistor. This is not easy to do. It is most likely to succeed with an additional coupling relay.

Example

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