Control system using incremental decoder


Thread Starter


I am designing a system to control a pneumatic acutator. As it needs to work under a magnetic enviornment, i think is a good idea to use an incremental decoder to sense the displacement and feedback to the computer for control. However, I know very little about it and would be very appreciated if anyone can point me to a good reference books, websites, journals, etc.

Also I want to buy some simple kit to test out my idea. If I just buy an oridinary photodiode and a LED, do i have to worry any compatability problem?

Thank you very much.

Robert Scott

People normally do not build their own incremental encoders from photodiodes and LEDs. You buy the completed unit with logic-level ouput in the form of two phases that are 90 degrees apart, and perhaps an index pulse as well. Look up BEI and other encoder vendors for more information.

-Robert Scott
Real-Time Specialties
Embedded Systems Consulting

Yuri Mitnick

I guess you are talking about incremental ENcoder. Hall position sensors are obsolete due to strong external magnetic fields.

To be exposed to AC brushless with incremental encoder without Hall sensors start-up (power-on) problems and approaches, read Smart Position Initialization article overview at