Re: [CAD_CAM_EDM_DRO] Encoder question

In a message dated 4/5/2005 1:48:48 AM Eastern Standard Time,
elson@... writes:
Yes, exactly. It is a pulse that goes true over a very short angle of
movement,
and is often referenced to a particular transition of the quadrature
signal, as well.
It is usually once per rev on shaft encoders. Some linear scales have the Z
repeat every so often, or arrange it so that its relation to the
quadrature signal
allows the DRO to figure out which specific repeat of the Z it just
passed over.
That's how the absolute DRO's work.

Jon
Exactly, however some rotory incremental encoders have 2 Z pulses per
revolution. In many applications, the OEM puts either a limit switch or proximity
sensor near the end of the reference travel on each axis and when the controller
sees this limit switch/sensor, it starts looking for the Z pulse and stops
when it sees that pulse. This allows for any change in the trip point of the
limit switch/sensor over time. As you indicated, in some cases they use the
relationship to the quadrature pulses for this.

My two cents worth, again,

Randy Abernathy
4626 Old Stilesboro Road
Acworth, GA 30101
Ph / Fax: 770-974-5295
E-mail: cnc002@...

I furnish technical support, repair, and other related services for your
industrial woodworking machinery. My background as Senior Service Engineer for the
SCMI Group for nearly fifteen years with factory training, combines with my
extensive background in electronics, mechanics, pneumatics, electrical and CNC
machinery to offer you needed support for your machinery.


[Non-text portions of this message have been removed]