The PT series of on-board I/O modules are DECOWELL's flexibly designed distributed expansion modules. The modules consist of an adapter, an I/O module, and a power supply module, and the PT series of on-board I/O modules can be integrated with various communication interfaces and functions through a customised backplane, which enables the miniaturisation of the control module and reduces the cost of installation and commissioning by means of pre-fabricated cables.