If you need electronic simulator with the ability to set the speed of the rotation, and start and stop on demand as in the actual system then check out this Encoder Simulator. The project very useful for troubleshooting or developing new programs for control systems when there is unavailability of the target system for experiment, risk of damage to the target, and physical distance of the developer from the target location.
This ATmega162 Based Encoder Simulator is programmed by the user through a simple Windows interface. Communication to the simulator is through RS232. Both 8 bit and 12 bit encoders are supported. In fact two simultaneous encoders can be simulated. Each of the two encoders can be programmed to increment at its own rate, so an effective gear ratio between the two can be produced. Start/stop of the encoders can be through the user program or a digital input from the target simulator. Additionally, a few digital outputs can be set to turn on and off at specific encoder positions to provide stimulus for the target simulator.
Thomas Kohan, the project designer, said that the MCU does all the work while the Windows program is just a user friendly terminal program. The Encoder Simulator uses LED‘s for visual feedback of rotation speed to the user.
Project Detail and Documentation (zip)