abs enc

Hi everyone

one of my frnd asked me abt absolute encoder retaining data. I said the tracks been inside so only data's are available. But He told me tat he had dismantled encoder wires and rotated an encoder and he checked the wires and he found some voltage. After removing the supply wires hw the voltage will come in encoder terminals? I told him there must an external pwr available with encoder. But my question is, is it right?

If you are referring to a single-turn absolute encoder then the code at the current position of the disk is the 'memory'. But you are probably referring to multi-turn encoders. This link discusses absolute encoders including multi-turn. But most multi-turn encoders I have used preserve the 'full-turns' information in digital circuitry which must be continously supplied with power. I haven't used any which write the 'full-turn' information to non-volitile memory.

could you be talking about a resolver?

http://www.amci.com/tutorials/tutorials-what-is-resolver.asp

checked the wires and he found some voltage

Click to expand...

also, don't forget a Digital MultiMeter will read voltage on my head... and there's nothing happening there