The 803-P12LH Rotating Cam Limit Switch by Allen-Bradley is a heavy-duty circuit control device used with industrial machines with repetitive operation cycles, in a wide range of applications where motion corresponds to shaft rotation. The device has a rotating switch, which rotates in any direction on any plane, and it is suitable for heavy-duty and long-lived industrial operations. The 803-P12LH is a control device in the Allen-Bradley 803 high-speed, low-cost internal adjustment, Style P series, and like all members in the series, it comes with a standard right shaft extension, and a base shaft speed of 400 RPM. The 803-P12LH has 12 control circuits with a cam-opened contact, 12 cam assemblies with adjustable cam segments, a spring-loaded cam-roller, and a rotating shaft with 400 RPM maximum shaft speed. It has a 25A normally closed (NC) contact with AC and DC ratings of 30/3A MAKE/BREAK contact ratings at 600 Volts AC and 230 to 250 Volts DC, and with 1800 Volts A MAKE/BREAK real power rating. The 803-P12LH has a higher (lobe) and lower (valley) cam segment, which activates and deactivates the circuit when it passes the cam-roller, and it also has a keyway slot which connects the shaft to machines.

The circuits are activated when the lobe brushes against the spring-loaded cam-roller, and the period of activation (dwell time) is determined by the size of the lobe. The circuit is de-activated when the valley passes under the cam-roller, and the cam is timed (timing) in degree, and the 803-P12LH like every Style P device, it has a cam duration range of 11 degrees to 349 degrees. It has an internal dwell time, and timing adjustment, and it has a left-hand shaft extension modification. The device has an operating temperature range of -30 degrees Celsius to 66 degrees Celsius (-22 degrees Fahrenheit to 150 degrees Fahrenheit), with a storage temperature range of -30 to 93 Celsius (-22 to 200 degrees Fahrenheit), and it is enclosed in a NEMA enclosure. The 803-P12LH has both cam and non-cam options, and it has an approximate weight of 19.1 kilograms (with full cams), and its total dimensions are 483.3  millimeters x 181 millimeters x 138.1 millimeters.