encoder wiring channel A and channel B

[senor J.]

I have 320 drives I am wiring up. I have shielded 2 pair wire for the encoders. Black and red are shielded together and white and green are shielded together. do I wire enc - and chanel B in the same pair or enc - and channel A? thanks for your help

[Al_The_Man]

Black & red, + & Com.
White & Green, A-B.
Al.

[morestuff]

I respectfully disagree with Al_The_Man.

Putting a differential signal on a twisted pair is desirable,
but in this case, encoder phase A and phase B are NOT
a differential signal.

A and B are quadrature signals, and as such they should
be prevented from having cross talk with each other.
Putting two single ended (non-differential) signals into
the same twisted pair will allow cross talk coupling. Since
you are using G320 drivers which have single ended
inputs and make no mention was made of converters, the
logical assumption is that you are using encoders with single
ended outputs.

The power and ground leads are intended to have a constant
voltage all the time and will couple less noise into the a
phase signal than would the opposite phase signal which is
a changing voltage signal.

When using an encoder with single ended outputs connected
through a cable with two shielded twisted pairs, I would
recommend the following:

Put phase A and Encoder Ground together in one twisted pair. I would
use Green for Ground and White for phase A.

Put phase B and Encoder +5V in the other twisted pair. I would use
Red for +5V and Black for phase B.

Connect the shields to ground (the negative supply for the
encoder) at the G320 end of the cable. Do not connect
the shield to anything at the encoder end of the cable.
This provides shielding, but prevents current from flowing
in the shield itself. Current flowing in the shield would
couple noise into the signal via a transformer-like action.

It is also important that the +5V and Ground have a filter capacitor
at or inside the encoder. Some HEDS encoders lack this capacitor.
See this Geckodrive application note if using HEDS encoders:

http://www.geckodrive.com/ark-2/supp...?pid=91&id=101

If you are using G320X drivers, you should also see the instruction
manual regarding the setting of DIP switch 6 for HEDS encoders.

Regards,
Steve Stallings
www.PMDX.com

[morestuff]

.... well my attempt to provide a link to the Geckodrive
application note about using HEDS encoders failed
because the web site uses dynamic links. To get to
the application note, go the www.Geckodrive.com
home page and use the following clicks to navigate:

>Support (on the selection bar at the top of the home page)
>Application Notes (from the vertical column of selections on the left side)
>Servo Drives (which appears below Applications Notes after you click there)
>Using HEDS Encoders (which appears below Servo Drives after you click there)

Regards,
Steve Stallings
www.PMDX.com