An incremental encoder that uses precision measuring
wheels to directly measure the movement of a conveyor belt or other
material.
Wheeled encoders more accurately track
the conveyor belt or other material than shaft encoders. Two problems with shaft
encoders in this application are: (1) slippage of the conveyor belt on the
roller, and (2) inaccuracy of roller diameters. Both of these contribute to
inaccuracies that reduce the overall efficiency of a material handling sortation system.
Wheeled encoders ride directly on the moving material, use a wheel tread having a
high coefficient of friction, and have a very low starting torque resulting in
virtually no slippage of the wheels on the belt. In addition, the wheels are
precision ground to 12.00 inch or 30.00 centimeter circumference with a
tolerance of +/- .01" or .025cm., versus a roller which has a much larger
tolerance and its circumference seldom translates into an integral number of
encoder pulses per unit of linear movement.
Photocraft model RH wheeled encoders offer additional advantages. The
integral arm on the encoder and various accessories make it easy to install. The
"anti-jitter" feature eliminates tracking problems and the resulting
miss-sorts often encountered when a conveyor stops and then restarts. The circuit
board includes a high degree of circuit protection that eliminates failures
caused by the very significant levels of static electricity often associated
with conveyors. Finally, we offer a "programmable" version of the RH
encoder that enables selection of the pulses per revolution and output circuit
type at installation time, resulting in maximum flexibility for you with minimum
inventory.
