We stock Siemens S5-135/155. When this system was introduced it was intended primarily for larger applications. The S5-135/155 is an advanced modular PLC system that in addition to digital I/O modules also offers analog I/O modules, modules for temperature measurement and temperature control, counters, positioning modules and more. The system is long obsolete but we can offer used/refurbished Siemens S5-135/155 spare parts from our stock.