The 803-F212RH Rotating Cam Limit Switch by Allen-Bradley is a Style F circuit control switch with a shaft-mounted cam that is used with machinery with repetitive operation cycles in processes where the shaft rotation corresponds to the machine’s motion. It is built for long-life and the heavy-duty operations, and it is used in applications like steel forming / heavy metal processing, assembling/packaging, and metal forming operations. The 803-F212RH has 2 heavy-duty circuits with snap action contacts and with 2-cam independently-operated cam assemblies with adjustable valleys and lobes. It also has a 150 RPM rotating shaft with over-sized ball bearings, a keyway (shaft slot) for connecting machines to rotating shaft, and a contact-mounted spring-loaded cam-roller. When the shaft rotates, the cam lobes glide against the cam roller, activating the circuit in the process, and when the cam valley passes by the cam roller, the circuit is deactivated. The 803-F212RH has a dwell time (cam activation duration), determined by the size and length of the cam lobe, and the device can achieve the maximum dwell time when the cam lobes offset at the maximum angle, and it can achieve the minimum dwell time when they are aligned.

The 803-F212RH has a timing in an angular degree which is the moment of cam activation, and it is determined by the position of the shaft-mounted cam relative to the keyway position and it has a minimum and maximum range of 12 and 348 degrees. The device has external adjustment settings for both the timing and the dwell time which is adjustable by using a screwdriver even while the machine is in motion, and the settings of both the timing and the dwell time determine the machine operation. The 803-F212RH has a right-hand shaft extension, unlike the standard left-shaft extension for most Style F devices, and it comes in a NEMA Type 1 Enclosure. It has a functioning temperature range of -30 to 66 degrees Celsius (-22 to 150 degrees Fahrenheit), with a storage temperature range of -30 to 93 degrees Celsius (-22 to 200 degrees Fahrenheit), and it is CE, CSA, and UL-certified. The 803-F212RH has aggregate shipping dimensions of 446.1 x 82.6 x 177.8 millimeters (17.56 x 3.25 x 7 inches), and an approximate weight of 5.4 kilograms (12 pounds).