The 803-F312RH is a rotating cam limit switch by Allen-Bradley that is a heavy-duty circuit control device in the Style F series, which is used with heavy-duty industrial machines with repetitive operation cycles, in processes where the motion directly equals the shaft movement. It makes use of a shaft-mounted cam which produces contact actuation as the shaft rotates and it is suitable for heavy-duty industrial machines with long operation lives. The 803-F312RH comes with 3 independent cam operators with adjustable cam segments (lobes and valleys) and 3 control circuits with a 10A snap action contact. It has a contact-mounted and spring-controlled cam roller, with a 150 RPM rotating shaft, and a shaft slot (keyway) which connects moving machine parts to the rotating shaft. The 803-F312RH circuit is activated when the cam lobes brush against the cam-roller assembly, and when the valley passes through the cam roller, the circuit is deactivated.

The device has a dwell time (a cam activated duration) which depends on the size of the cam lobes and which can either be at the maximum or the minimum depending on the angular alignments of the cam lobes. The 803-F312RH has a timing in a degree corresponding to the position of the cam on the shaft with reference to the keyway, and like all Style F devices, it has external adjustments for both dwell time and timing, which is done by using a screwdriver while the machine is still in motion. It has a right-hand shaft extension modification and a cam duration range of 12 to 348 degrees. The 803-F312RH has a working temperature range of -30 to 66 degrees Celsius (-22 to 150 degrees Fahrenheit), with storage temperature limits of -30 to 93 degrees Celsius (-22 to 200 degrees Fahrenheit), and it is suitable for rugged industrial environments. It weighs about 5.4 kilograms (12 pounds), with approximate dimensions of 446.1 x 82.6 x 177.8 millimeters (17.56 x 3.25 x 7 inches), and it is CE, UL, and CSA-certified.