Inductive Encoders.How do they work? Are they more accurate? Reliable ?

Good Morning ,

I was asked a question that I could not answer ( Like many questions I can't answer ) . It was concerning Inductive Encoders. I have never heard of them. Could you folks please offer some feedback on these. I googled them and found some good information on them , but mainly from their manufactures. How do they work ? Are they more accurate ? What temperature can they handle ? How do they interface with a PLC ? How reliable are they ?

Thanks in advance ,

http://www.zettlex.com/articles/optical-encoders-versus-inductive-encoders/

The above article compares optical to inductive encoders.
The interface to the PLC will depend on the type of encoder, absolute or incremental.

Hope this helps you out.
Regards,