setp encoder scale by mux2

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11 Oct 2017 10:45 #100201 by billykid
billykid created the topic: setp encoder scale by mux2
I wanted to select two spindle encoder scales, one for orient mode and one for speed by means of a mux2.
but connecting the output of the mux2 setp hm2 ...... encoder.scale does not work.
they are both float but float rw encoder pin.
any suggestions ?
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11 Oct 2017 15:39 #100215 by PCW
PCW replied the topic: setp encoder scale by mux2
Encoder scale is a parameter, not a pin so cannot be linked to a signal

Normally spindles are scaled for revolutions so the encoder velocity is in RPS
If you want RPM its probably easiest to use the scale component and multiply the
RPS number by 60 to get RPM
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12 Oct 2017 12:19 #100271 by billykid
billykid replied the topic: setp encoder scale by mux2
I thought you could change the parameters with a command but that is not the case.
I used a scale and it works fine.
Pcw, I posted a small error in the 7i40 manual I do not know if you read it, and I asked in the other post where it was about 7i40 if you can connect a motor.

forum.linuxcnc.org/27-driver-boards/33261-5i23-two-7i40-7i37
forum.linuxcnc.org/27-driver-boards/33336-7i40-manual-issue

thanks for your patience
regards
Mauro
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13 Oct 2017 12:48 #100321 by andypugh
andypugh replied the topic: setp encoder scale by mux2
If you change the scale then the position output will change by a _lot_.

One solution would be to use two separate encoder counters with different scales sharing the same input. Another (more efficientt, probably) is to scale one output.
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13 Oct 2017 18:43 #100330 by billykid
billykid replied the topic: setp encoder scale by mux2
Thanks Andy,
we were today with my friend doing the tests.
we used the solution to scale an output as you said and it works pretty well.
there is a problem, the orientation is at a very low speed of 15 millivolt max and the 7i33 by a stop of -5 millivolt.
will be brought to zero, now I see how to do it.
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13 Oct 2017 18:47 #100332 by andypugh
andypugh replied the topic: setp encoder scale by mux2
There is an "inverse deadband" component that might help there.
wiki.linuxcnc.org/cgi-bin/wiki.pl?Contri...idb_Inverse_Deadband
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14 Oct 2017 19:00 - 14 Oct 2017 19:01 #100355 by billykid
billykid replied the topic: setp encoder scale by mux2
I've seen but I do not understand if it can serve.
the problem that the spindle enabled turns very slowly instead of being stationary.
because from 7i33 they leave about 5 millivolts at zero speed.
the fanuc ac drive is in place because without the input it is perfectly firm.
you say i can use inverse deadband?
Last Edit: 14 Oct 2017 19:01 by billykid.
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14 Oct 2017 19:09 #100356 by PCW
PCW replied the topic: setp encoder scale by mux2
Slow drift should be expected with a analog servo if there is no feedback.
Since you have an encoder, why dont you close the feedback loop?
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14 Oct 2017 19:42 #100358 by billykid
billykid replied the topic: setp encoder scale by mux2
I have two pid, one speed and one position for spindle orientation, fanuc servo ac has its encoder.
orientation is not very accurate but it works.
the drive accepts 0 to +10 volts and fwd and rev. with zero input is perfectly firm.
now unfortunately I do not have the last files because I'm at home.
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14 Oct 2017 19:51 #100359 by PCW
PCW replied the topic: setp encoder scale by mux2
If it drifts in position mode, the PID is not working
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