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Clearpath HLFB Use

Posted: Thu Jan 23, 2020 11:10 pm
by afeathers1
Just curious if anyone has experimented with a deviation from centroid's schematic using for Clearpath servos.

What I'm referring to is the use of an additional relay board to 'AND' together HLFB outputs from individual servos to one 'NO' signal.

It seems that you could source HLFB signal current from one of the Acorn board inputs, and daisy-chain that through the servos (Input to HLFB+ of servo X, HLFB- of servo X to HLFB+ of motor Y, HLFB- of motor Y to HLFB+ of motor Z, etc., etc., to common)

Has anyone tried this? I've had similar success with daisy-chained PNP prox home switches, provided NPN conversion logic at the input.

Just trying to keep the setup uncluttered. I'll certainly use relays if necessary.

Might try it if nobody has.

Thanks and regards,

- Austin

Re: Clearpath HLFB Use

Posted: Thu Jan 23, 2020 11:54 pm
by Gary Campbell
Austin...
I do it all the time with closed loop steppers and ClearPath servos.

Here's a video from a couple years back:

Re: Clearpath HLFB Use

Posted: Fri Jan 24, 2020 3:07 am
by afeathers1
Hi Gary,

Thanks for the post. You've put together an informative video regarding the relay solution.

What I'm curious about is going about using the isolated nature of the HLFB circuitry in the clearpath servos to daisy-chain the "Drive OK" signal through them, without the use of relays.

I don't have an additional relay board available, but will pick one up if this isn't possible.

Thanks and regards,

- Austin

Re: Clearpath HLFB Use

Posted: Fri Jan 24, 2020 8:58 am
by Gary Campbell
This is one of those 'in Theory" issues. Teknics says it will work, Centroid USED TO SAY it should, but in the real world it doesn't. Try if you wish and report back, but I haven't seen more than 2 daisy chained HLFB signals work reliably.

EDIT: Changed Centroids position (was looking at an old schematic) Always make sure yours are the "latest and greatest"

Re: Clearpath HLFB Use

Posted: Fri Jan 24, 2020 9:55 am
by cnckeith
correction centroid does not recommend daisy chaining clearpath HLFB signals.. please follow the centroid recommended hookup for clearpath, schematic #14972
S14972.r2.pdf
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