Siemens plc i/o module, 24v dc supply voltage, 8 digital inputs - simatic s7-300 series - 6es7221-1bf32-0xb0. Ensure the efficient and safe transfer of energy across your plc (programmable logic controller) devices with this communication module from siemens. It’s fitted with multicoloured led lights and a diagnostic alarm, so you can check on operating status at a glance. The alarm is triggered when an electrical fault or circuit break occurs, which notifies users of potential hazards and the need for repairs.