Differential for Encoders?

[Jeshua]

Greetings,

I have to have two of my servos connected to my Gecko 320s with more than 6 feet of cable (I guess I will need around 12 feet).

Do you think it might work without differential signals?

The two servos in question have a US Digital encoder (HEDS-9100-A00).

I assume I would need something that connects to the US digital encoder that converts the signal to differential, then another device that connects to the Gecko 320 that converts the differential signal back into what the Gecko expects.

Can anyone recommend a source for reasonably cost signal differentials?

Thank you!

[BobWarfield]

Sure it can work. I run more than 6 feet. You need to do a couple of things to maximize you chances.

First, run shielded cable and ground the cable at you electronics enclosure end rather than at the machine.

Second, since you're running HEDS encoders, be sure to add the bypass capacitors Mariss F. has recommended.

I'm not having any problems since having done those two things.

For more on the bypass caps for HEDS, go to this page:

http://www.cnccookbook.com/CCMillCNCHome.html

and search for HEDS.

Cheers,

BW

[keebler303]

Its probably worth trying first without the differential signals.

If you have problems, US Digital sells differential drivers/receivers to convert your encoder to differential signals. I don't know if you would consider it a resonable cost or not.

If you are moderately electronically inclined, you can easily fabricate them yourself and save some money by using 26ls31 and 26ls32 chips. They can be had from digikey or elsewhere for a buck or less.

Matt