There's a kernel module called piControl (source code is on GitHub) which periodically polls the I/O modules. The values written to the outputs are taken from a

There's a kernel module called piControl (source code is on GitHub) which periodically polls the I/O modules. The values written to the outputs are taken from a memory area called the "process image". Values read from inputs are stored in that same memory area. User space accesses the memory area via regular open/read/write/close system calls. Plus there's a bunch of ioctls to perform special actions such as firmware updates on the I/O modules. You may use whatever language you prefer. There's a Python module called RevPiModIO, authored by a member of the Revolution Pi community, Sven Sager: https://revpimodio.org/en/homepage/ https://revpimodio.org/en/homepage/ A NodeRED module was contributed by another customer, Erminas: https://flows.nodered.org/node/node-red-contrib-revpi-nodes https://flows.nodered.org/node/node-red-contrib-revpi-nodes If you're into Structured Text, there's a software called logi.RTS included in our image (needs a license for unlimited use, 1 hour is free).