The Allen-Bradley 803-F812RY is a Rotating Cam Limit Switch of the family of 803 switches. This device is used to open and close contacts on precisely defined positions of its shaft, whose speed is directly proportional to the machine mechanism to which it is connected. This sensing switch is attached over a solid connection or a chain to the target machine, which executes repetitive control operations. It is used for applications such as mechanical presses, packing machines, and material handling mechanisms. It is mechanically built for installation in any plane and its shaft can execute switching functions by rotating either CW or CCW.

This is a “Style F” device and as such has the special feature of external dwell and timing adjustments. Timing and dwell adjustments are to be set even when the device is operating. The 803-F812RY has 8 independent control circuits (1NO / 1NC contacts, 10A rated, snap action). Each can be set for operation by belonging to the cam assembly at any desired shaft angular position. This bulletin 803 device has an RY code extension, which means that its gear ratio is not the standard one.  A suffix code should be added to determine exact gear ratio. For example, 75TO1 (full code example 803-F812RY75TO1). The Allen-Bradley 803-F812RY weight is approximately 14 pounds (6.4 kilograms) and its dimensions excluding the shaft are 312.7 x 177.8 x 82.6 millimeters (12.31 x 7.00 x 3.25 inches). Its operating temperature range is -22 degrees Fahrenheit at the minimum and 150 degrees Fahrenheit at maximum (-30 to 66 degrees Celsius). Allen-Bradley is no longer producing this part, since 2007.