Festo SIEN-4B-PO-K-L Inductive Proximity Switch

The Festo SIEN-4B-PO-K-L inductive proximity switch is a compact 4 mm sensor that detects metallic objects without contact in pneumatic automation and machine control. Its flush-mount design and IP67 enclosure suit space-constrained installations across pneumatic actuators, cylinders, conveyors, packaging lines, and robotic cells, delivering reliable position sensing and feedback signals. Core specs include operating voltage 10–30 VDC, max output current 200 mA, and a 3-wire PUR cable with a 2.5 m length. It switches via a PNP output in a normally closed configuration, with a nominal sensing distance of 0.8 mm and an assured distance of 0.64 mm, and it supports high switching rates up to 3000 Hz. Built with a high-alloy stainless steel housing for rugged industrial use, the SIEN-4B-PO-K-L is designed for continuous operation from −25°C to +70°C and carries EN 60947-5-2, CE, UL, and RoHS compliance. Typical replacements include the SIEN-4B-PS-K-L and SIEN-4B-NO-K-L, as well as the SMC D-M9B Auto Switch Proximity Sensor, making it suitable for OEM retrofits, sensor replacements, and automation maintenance on automatic production lines.