Incremental encoder for low speed applications

ROTALINK has released an incremental dual channel encoder which is available across its range of modular brushed DC motors and gearboxes and is suitable for numerous low speed positioning applications.

Addition of the incremental encoder is claimed to provide the ability to position components with an accuracy limited only by the 2° backlash of the gearbox. The original purpose of the encoder was to offer closed loop control and provide users with the benefit of feedback from the gear motor, where normally this would be impractical due to cost.

One of the most common uses is precisely controlling the speed of a peristaltic pump, and the amount of fluid it dispenses. Without the encoder, the varying tolerances in motor output and wear in the pump tube can cause gear motor speed to vary by as much as 15% and so compromise pumping accuracy. Other examples of low speed applications include positioning rotary valves in water softeners, transferring filters from cinema projectors, panning CCTV cameras and positioning a chute in a cash dispenser.

The encoder can also be used for basic closed-loop positioning and whilst it still requires a single limit switch, it has the ability to move to multiple positions as opposed to between two extremes defined by a pair of limit switches.

The incremental encoder offers a range of output options up to 48ppr, is available in single or dual channel configurations and size variants of 28, 42 and 52mm. This layout provides a ‘sandwich’ mount between the standard Rotalink single shaft DC motors and gearboxes which provides the dual benefits of protecting the encoder and making efficient use of space. It is said to feature a capacitance design based around a custom ASIC with internal amplification, can directly drive TTL logic, is designed to operate over a wide range of temperatures and is unaffected by external magnetic forces.