In the future there will be larger versions of Industruino with more I/O. Currently the best way to add extra I/O is to connect extra IND.I/O's together via the RS485 connection. The RS485 connection allows you to connect a maximum of 32 units togerher via the same 3 core cable. You can then have one Industruino act as a master and retrieve the I/O status of the other slave units.
I think you can multiplex digital inputs on one analog input using resistors you will shunt with your dry contact inputs and the 24 Vdc power supply to generate a 0-20 mA current. I have this idea on a side burner for now, but it will come to the front quite soon.
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