On Sun, 09 Jan 2011 15:04 -0800, "Kirk Wallace" <[email protected]> wrote: > On Sun, 2011-01-09 at 12:41 -0600, Jon Elson wrote:
> > The hal component encoder is a specific implementation of an encoder, > > equivalent in function > > to a general encoder counter module which might be partly implemented in > > hardware or software. > > I think the term encoder has been used rather loosely, but Wikipedia > states: > " > An encoder is a device, circuit, transducer, software program, algorithm > or person that converts information from one format or code to > another,... > " > > To me, that means a rotary disk and sensor encodes position information > into a set of quadrature signals. Then, I consider that the quadrature > signals are "decoded" by the misnamed encoder component into counts > which are then stored and managed by a count/position register -- > encoder => decoder => counter. Technically you are probably correct, but if we used that nomenclature we would confuse the hell out of everybody. In the CNC world, the encoder is the thing connected to a shaft that generates the pulses. To be precise we should say "absolute encoder" or "incremental quadrature encoder" or one of several other possibilities, but the default meaning is "incremental quadrature encoder", and when we refer to encoder signals we mean quadrature, possibly with an index pulse. The HAL component is technically a decoder and counter of those signals, but if we called it a decoder people would be really confused. Calling it an "encoder counter" or "encoder interface" would be better than just "encoder", but people usually know what we mean. Likewise, hardware boards that support quadrature signals with or without index pulses usually call them "encoder inputs" or "encoder counters". > It's really just mice nuts, but I'm doing jury duty right now, so I may > me in a lawyer's frame of mind. Lawyers, ewww. -- John Kasunich [email protected] ------------------------------------------------------------------------------ Gaining the trust of online customers is vital for the success of any company that requires sensitive data to be transmitted over the Web. Learn how to best implement a security strategy that keeps consumers' information secure and instills the confidence they need to proceed with transactions. http://p.sf.net/sfu/oracle-sfdevnl _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
