2.7.15

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27 Feb 2020 15:45 - 27 Feb 2020 15:51 #158644 by PCW
Replied by PCW on topic 2.7.15
It has been fixed but hal files created before the fix will need to be updated
Last edit: 27 Feb 2020 15:51 by PCW.

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27 Feb 2020 23:35 #158698 by andypugh
Replied by andypugh on topic 2.7.15
Only faulty HAL files, though it is possible that pncconf wasn't making them correctly and nobody noticed.

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28 Feb 2020 06:15 #158727 by cmorley
Replied by cmorley on topic 2.7.15
They were not faulty when Pncconf built them originally.
PID behavior was changed (I guess nobody thought to check how the configuration programs used them)

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28 Feb 2020 10:30 #158737 by andypugh
Replied by andypugh on topic 2.7.15

They were not faulty when Pncconf built them originally.


The HAL shown earlier had a signal connected to pid.N.command-deriv, but there was no driver for that signal.

While command-deriv was broken and ignored, that didn't matter, but I don't think it was correct.
It's curious that the command-vel output from motion (which I think is the correct signal to drive command-deriv) lives in the "debugging pins, might be removed" section.

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28 Feb 2020 16:53 #158764 by cmorley
Replied by cmorley on topic 2.7.15
Yes that was a bad choice for the PID component. but when pncconf originally was built that was fine - in fact there are lots of pins that pncconf adds signals to but not driving pins. It does so so that added HAL code files could be more consistent.
Breaking a system because you added a signal to a pin is not user friendly.
The following user(s) said Thank You: tommylight

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28 Feb 2020 19:39 #158779 by PCW
Replied by PCW on topic 2.7.15
The problem was that the PID component had a bug (it ignored the command-deriv pin)
The fix implemented simply made the PID component match its long standing manual page description, that is, make the PID component calculate the command derivative internally if the command-deriv pin was unconnected but use the command-deriv pin value if connected.

This matches the feedback-deriv pin behaviour, and any other fix (mode pins etc) would likely have much broader impact.
The following user(s) said Thank You: tommylight

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28 Feb 2020 20:33 #158782 by cmorley
Replied by cmorley on topic 2.7.15
yes but breaking peoples systems on a released version is not helpful.
Especially since it's very difficult to find the problem, if you don't know about the special behavior.
Adding the fix to master would have been ok (Though I still disagree with the black magic)
I realize nobody did this on purpose - but telling people that adding a signal to a pin that is not connected to another driving pin is incorrect - is wrong - other then for the PID component.

Chris

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28 Feb 2020 20:49 #158785 by PCW
Replied by PCW on topic 2.7.15
I agree that this should have been left in 2.8 and later.

I do think that making command-deriv match the manual page and
feedback-deriv behaviour has the least impact on existing hal files
while fixing a even more mystifying bug (command-deriv having no effect)

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04 Mar 2020 09:14 #159173 by jazial
Replied by jazial on topic 2.7.15
Hello,

some time today to try to update the machine

I've added :
# --- added for 2.7.15
net x-vel-cmd <= axis.0.joint−vel−cmd

but halfile is not interpreted after this line (all signals after this one are ignored)

In Hal viewer, net x-vel-cmd is only connected to pid.x.command-deriv

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04 Mar 2020 12:05 #159186 by jazial
Replied by jazial on topic 2.7.15
Here is the error
twopass: Error in file ./my_LinuxCNC_machine.hal:
    Pin 'axis.0.joint−vel−cmd' does not exist

what I don't understand is the line
net x-pos-fb               =>  axis.0.motor-pos-fb
is working, so the axis.0.xxx pins are available

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