Biesse Rover 322 MESA retrofit

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6 years 4 weeks ago #184726 by tom_no
Got some good progress this week, getting drives activated and somewhat running. Encoder scales and directions plus homing seems to work perfectly. However, I'm struggling bigtime with the servo tuning. I have found settings that allow jogging up to a certain speed, but get "not following error" when increasing speed. I suspect I've arrived at Calibration values that "work", but probably are far from sane.

Need help pointing out where I've taken the wrong turn and how to get back on the right track.

I think my Output scale is way off, but if I bring it down to 10 as suggested in the guide the machine literally jumps (all 3.7 tons of it). It tries to move quite violently and immediately shuts down (faults out in LCNC). I've attached my HAL and INI files for reference.

Any and all suggestions will be greatly appreciated.

File Attachment:

File Name: Biesse_Rover_322.hal
File Size:10.22 KB

File Attachment:

File Name: Biesse_Rover_322.ini
File Size:3.75 KB

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6 years 4 weeks ago #184737 by PCW
Replied by PCW on topic Biesse Rover 322 MESA retrofit
A couple of things

if you have an output scale of 150 the limits must be +- this number:

OUTPUT_SCALE = 150
OUTPUT_MIN_LIMIT = -150
OUTPUT_MAX_LIMIT = 150

2. If these are velocity mode drives, most of the tuning will be done with FF1
Further, if you have OUTPUT_SCALE set correctly (the velocity at 10V)
FF1 == 1.000

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6 years 4 weeks ago #184743 by tommylight
The servo period in the ini file has to be 1 or max 2 million, not 6M.
The output scale is wrong for all axis, it should be 10 for the min and max you are using.
Refer to this topic for tuning, wiring and checking everything:
forum.linuxcnc.org/10-advanced-configura...ning-detailed-how-to

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6 years 4 weeks ago - 6 years 4 weeks ago #184744 by PCW
Replied by PCW on topic Biesse Rover 322 MESA retrofit
I would tend to disagree on the output scale. ideally it should be the machine
velocity (in machine units per second) at 10V, so 10 makes senses if the maximum
speed is 10 mm/second (at a full scale 10V output)

The reason to use this scaling is:
1. FF1 == 1.000
2. PID values are the same for inch and metric machines
3. All the PID values are in normal engineering units
for example, a P value of 1 means: correct the velocity
by 1mm/s for a 1 mm position error
Last edit: 6 years 4 weeks ago by PCW.

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6 years 4 weeks ago #184747 by tommylight
In that case, would the min and max output have to be scaled accordingly or remain at -10 and 10 ?

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6 years 4 weeks ago #184749 by tom_no
Thanks for input Peter! I'll update the limits tomorrow and test again.

The drives are Yaskawa Servopacks and may well be velocity mode drives. How do I tell for sure?

Can I calculate the correct OUTPUT_SCALE from maximum speed at 10V? IE 75 m/min = 1250 mm/sec?

Also; Having you here; RS-485 control of the VFD should be possible through the 7i77 and it's sserial port, right?

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