Joe, Yes more channels are usually needed for direction sensing. Single channel can do it, but it is more difficult, and requires ajustment of the periferal devise. But most of all the encoders I use (on motors and servos) are dual channel with a extra reference channel. Servos are usually fitted with a resolver.
Let me clarify what I said regarding counting. You are correct that the encoder does not count. The devise receiving the signal does.
I think we both are correct in our statements, I may have not provided enough information to you to make sense of my statements.
I am not going to get into a "who knows more" match with you. I am not a testing engineer. I just have worked with VFD's and other equipment that employ encoders and resolvers. Also measurement equipment ect..., that incorporate encoders on the equipment. But my statement regarding direction is sensed by the postive or negative output of the encoder. Turn an encoder in one direction it is a postive square wave relative to zero. And turn the other direction it is a negative square wave. Or Visa Versa.
The encoder is not smart. The devise receiving the signal is the smart one. It just receives the signal and does what it is programmed to do. Maybe we should discuss the smart equipment and leave the simple encoder to rest.....John
