The large brick-type open source PLC has 22 digital inputs, 6 analog inputs and 16 transistor outputs. It also features a SD card socket, 2 RS-232 ports, 1 RS-485 port, 1 USB device port and a JTAG port for programming and debugging.
All the source files including circuit diagrams for building the large open source PLC are available for download at the above link.