The 803-F812P6 Rotating Cam Limit Switch with an Adjustable Cam option is a circuit control device by Allen-Bradley that is used for heavy-duty machinery with repetitive operation cycles. It is used in industrial applications where machine speed directly correlates to shaft rotation. The 803-F812P6 is built for long-lived, heavy-duty operations, and it makes uses of shaft-mounted cams which actuate circuits as the shaft rotates. The device comes with one 8A snap action NC contact block, a NO contact block, and a rotating shaft with 150 RPM maximum shaft speed, and a spring-controlled cam roller assembly. The rotating shaft has over-sized ball bearings, with an internal slot (keyway) which provides connection to machines, and the rotation of the shaft initiates contact actuation. The 803-F812P6’s cam assemblies have adjustable cam upper (lobe) and lower (valley) segments, which activates and deactivates the circuit as it passes by the cam roller assembly, and the total activation period (dwell time) which is determined by the cam lobe size, can either be set at a maximum or a minimum depending on the angular alignment of the cam lobes.

The device achieves maximum dwell time when the cam lobes are offset at the maximum angle, and when they align they provide the minimum dwell time. The device has an operational (activation) timing, determined by the position of the cam on the shaft, relative to the key, and like all Style F cam devices, it has a cam duration range of 12 to 348 degrees. The 803-F812P6 timing and dwell time can be adjusted externally while the machine is moving, and it has an internally adjustable cam option, with 6 available substituted cams for adjustment. It has a standard left extension, with dust-tight and oil-tight NEMA Type 13 enclosure, and it has a functional temperature range of -30 to 66 degrees Celsius (-22 to 150 degrees Fahrenheit) with a storage range of -30 to 93 degrees Celsius (-22 to 200 degrees Fahrenheit). The 803-F812P6 weighs approximately 6.4 kilograms (14 pounds), with dimensions of 177.8 x 82.6 x 312.7 millimeters (7 x 3.25 x 12.31 inches).