I'm surprised this question doesn't appear in the forums or blogs. I figured I'd ask here rather than thru a support email....
I have a project that requires 100+ GPIO connections. Do you have any recommended hardware for GPIO expansion? I'd prefer not to add a second Arduino/RasPi PLC. It would also be nice to just have a I2C GPIO expander rather than having to interface Modbus and learn some kind of proprietary protocol.
I'm considering just buying multiple PLC controllers and learning NodeRed as a transparent way to access their GPIO with minimal firmware, but I'd really prefer zero firmware and microcontroller involved in the extra GPIO. Does Industrial Shield sell additional standalone I2C modules like the ones in the RasPi PLCs? Or do you have a preferred vendor for GPIO PLCs?