Open loop ok, no operation in Axis

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10 years 8 months ago - 10 years 8 months ago #70752 by djs14
Guys not sure if this belongs here or in the Axis section.

I got both X and Z axes moving in open loop and reading position feedback but when I open in Axis the axes just drift.

I see the feedback position moving with the drift ... like the control is not closing the position loop so it is not holding position.

I have a feeling it's just some fundamental error preventing enable ... like an estop input or something that got added in there while I was pasting things together.

Have a look at my files and see if anything jumps out.

cheers

File Attachment:

File Name: MiyanoLath...-3-4.hal
File Size:11.25 KB


File Attachment:

File Name: MiyanoLath...-3-4.ini
File Size:2.81 KB


File Attachment:

File Name: another-2.clp
File Size:9.99 KB


File Attachment:

File Name: panel-2-3-4.xml
File Size:982 B


File Attachment:

File Name: spindle_to...-2-3.hal
File Size:537 B


The drives have no separate enable pins.

Thank you
Last edit: 10 years 8 months ago by djs14.

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10 years 8 months ago - 10 years 8 months ago #70754 by PCW
This is expected since the P terms are 0

HOWEVER be aware that you may get a runaway as soon as you set a non-0 P term

So its crucial that your drive enables be under LinuxCNC control so LinuxCNC can disable the drives if a following error is sensed
Last edit: 10 years 8 months ago by PCW.

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10 years 8 months ago - 10 years 8 months ago #70767 by djs14

PCW wrote: This is expected since the P terms are 0

HOWEVER be aware that you may get a runaway as soon as you set a non-0 P term

So its crucial that your drive enables be under LinuxCNC control so LinuxCNC can disable the drives if a following error is sensed


Thank you for the response. I tried P values of 50.0 on both axes and still they are creeping.

The strange thing to me is the commanded position is moving with the creeping. Shouldn't the controller be sending a position of zero as command? Instead it is following the axis. It makes sense how an axis creeps especially in velocity mode when sitting idle in open loop because any voltage is a velocity ... but if it is closing position loop which should be zero, why is the commanded position moving? Following error staying at zero also..

What else could I look at?

Thank you for any thoughts.

cheers

edit: motors are unhooked from machine so no damage will occur if they run away
Last edit: 10 years 8 months ago by djs14.

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10 years 8 months ago - 10 years 8 months ago #70769 by PCW
Are you sure the commanded position is creeping?
( Axis's DRO shows the feedback position, not the commanded position )
Last edit: 10 years 8 months ago by PCW.

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10 years 8 months ago #70774 by djs14

PCW wrote: Are you sure the commanded position is creeping?
( Axis's DRO shows the feedback position, not the commanded position )


I'll double check it is command.

The function boxes in the axis gui are grayed out/not clickable if that means anything.

If following error was staying zero wouldn't that mean the command is equal to feedvack? I will double check.

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10 years 8 months ago #70775 by djs14
Analog out is zero.

It is like it is just minimal voltage on the analog output.

The e stop doesn't seem to do anything. Just throwing out observations.

I will double check there are not enables on the drives I have brain faded.

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