Encoder for axis tacho feed back

Have you read my post in the past?

What about polarity of your simulated output to servodrive?
I wrote you that Feadback from tacho always Positive.

PCW replied
"Maybe the Fanuc Tachometer simulator is unipolar?

You might try running the velocity through the abs component
before feeding it to the analog output hardware so the velocity signal
is always positive"


I have not been able to run (or understand) the abs component , to get, only positive tacho feedback, and as I do not know where to start.
Any advice or direction will be most appreciated.

At present all I have managed is to add ,
loadrt abs count=1
addf abs.0



net x-pos-fb <= hm2_5i24.0.encoder.00.position
net x-vel-fb <= hm2_5i24.0.encoder.00.velocity
net x-pos-fb => joint.0.motor-pos-fb
net x-index-enable joint.0.index-enable <=> hm2_5i24.0.encoder.00.index-enable
net x-pos-rawcounts <= hm2_5i24.0.encoder.00.rawcounts


net x-enable hm2_5i24.0.7i83.0.4.analogena0
net x-vel-fb hm2_5i24.0.7i83.0.4.analogout0
setp hm2_5i24.0.7i83.0.4.analogout0-maxlim 277.7777
setp hm2_5i24.0.7i83.0.4.analogout0-minlim -277.7777
setp hm2_5i24.0.7i83.0.4.analogout0-scalemax 277.7777

cheers john

loadrt abs count=1
addf abs.0 servo thread


net x-pos-fb <= hm2_5i24.0.encoder.00.position
net x-vel-fb <= hm2_5i24.0.encoder.00.velocity
net x-vel-fb => abs.0.in
net x-vel-fb-abs <= abs.0.out
net x-pos-fb => joint.0.motor-pos-fb
net x-index-enable joint.0.index-enable <=> hm2_5i24.0.encoder.00.index-enable
net x-pos-rawcounts <= hm2_5i24.0.encoder.00.rawcounts


net x-enable => hm2_5i24.0.7i83.0.4.analogena0
net x-vel-fb-abs => hm2_5i24.0.7i83.0.4.analogout0
setp hm2_5i24.0.7i83.0.4.analogout0-maxlim 277.7777
setp hm2_5i24.0.7i83.0.4.analogout0-minlim -277.7777
setp hm2_5i24.0.7i83.0.4.analogout0-scalemax 277.7777

Many thanks PCW for your reply.

The Fanuc Tachometer simulator is not unipolar, when using the abs component.
A negative, axis motion command, will result in instant motor runaway.
A positive , axis motion command , will result with correct movement.

I intend to try another servo drive ,motor combination that is known to be correct .

cheers john