A-M-C A12A100 Servo Drive with SouthWestern Ind ProtoTrak Plus

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5 years 8 months ago #198562 by PCW
Unfortunately those traces are not of much use.

You need a trace like the previous one:

forum.linuxcnc.org/media/kunena/attachme...45f2-.1236feed20.png

with a jog showing acceleration and a constant speed region (the regions Todd circled)

You tune FF1 first to minimize the following error during constant speed motion

Then you tune FF2 to minimize the error during acceleration and deceleration

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5 years 8 months ago #198563 by new2linux
PCW, Thanks for your help!! Attached is a pic of low P as you have suggested. Feed rate 50.9"/min!! Many thanks!

Edit: New pics, better f-error? 1 trace with FF2, 1 w/o FF2. Tried to be in center of the zone. I will work this over the weekend, please point out any suggestions or I will work with the guidance provided. many thanks!! Take notice the units are not uniform!

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5 years 8 months ago #198564 by PCW
So you still have a FF2 value set, it should be 0 at this point

Next step is to dial in FF1

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5 years 8 months ago #198701 by new2linux
PCW many thanks, for your help!! I have worked on this a great deal, but only saved the pics you see. Only 1 of the 3 has any FF2, the units for the scale are not the same in all pics. The best error looks to be under 3 units (in the higher scale, even though the trace looks like no improvement) around 2.8 in 5m/unit scale. When adjusting the settings, I was tiring to flatten out the f error trace.

Many thanks!

PCW, this is from another post, can FF1 be calculated?:
PCW, I have read this (calculating FF1) several times, can I work with? This is from this link, tommylight as written: forum.linuxcnc.org/10-advanced-configura...ning-detailed-how-to
"Added 22.08.2019
-PCW mentioned several times that the FF1 value can be:

You either calculate FF1 (10/velocity@10V)
or
scale the analog output in velocity in which case FF1 = 1.0"

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5 years 8 months ago #198737 by PCW
What mode are you running the drive in? It does not appear to be running in velocity mode

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5 years 8 months ago #198743 by new2linux
PCW, Current mode. I will edit my 1st post.

many thanks

This is new traces with very low FF1 & FF2, feed rate 60"/min!! The file name has settings or read from the pic. ALL prior tuning had DeadBand set to a value, this is not the case now. The units are not uniform, see the screen shot.

many thanks!

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5 years 8 months ago #198771 by PCW
Ok for a single LinuxCNC PID loop driving a torque mode drive I would try this:

Start with all PID settings=0 except a bit of P, say 10 or 20

1. Set D as high as possible without buzzing/oscillation
2. Then set P as high as possible without oscillation
3. Next tune FF2 for the lowest following error during accel/decel
4. Finally increase I until you get oscillation (watch out you can get large motion)
then set I to about 1/2 the value that first caused oscillation

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5 years 8 months ago #198806 by new2linux
PCW, Many, many thanks!! As be clear is:

"1. Set D as high as possible with buzzing/oscillation"

or is that "with" or "without"?

many thanks!

Attached are the latest halscope trace. The file name has the settings, units are not sorted.

Many thanks

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5 years 8 months ago #198810 by PCW

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5 years 8 months ago #198960 by new2linux
PCW, Many thanks! Attached are several pic of the hal trace. There is an order the gain values are not uniform, please see pic for settings. The feed rate was only 29"/min. Did not see the big oscillation, as though with the "I".

many thanks!

Edit: PCW, this is from another post, can FF1 be calculated?:

PCW, I have read this (calculating FF1) several times, can I work with? This is from this link, tommylight as written: forum.linuxcnc.org/10-advanced-configura...ning-detailed-how-to
"Added 22.08.2019
-PCW mentioned several times that the FF1 value can be:

You either calculate FF1 (10/velocity@10V)
or
scale the analog output in velocity in which case FF1 = 1.0"

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