Open loop ok, no operation in Axis
28 Feb 2016 16:30 - 28 Feb 2016 16:31 #70752
by djs14
Open loop ok, no operation in Axis was created 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
The drives have no separate enable pins.
Thank you
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
The drives have no separate enable pins.
Thank you
Last edit: 28 Feb 2016 16:31 by djs14.
Please Log in or Create an account to join the conversation.
28 Feb 2016 17:33 - 28 Feb 2016 17:34 #70754
by PCW
Replied by PCW on topic Open loop ok, no operation in Axis
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
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: 28 Feb 2016 17:34 by PCW.
Please Log in or Create an account to join the conversation.
28 Feb 2016 21:00 - 28 Feb 2016 21:01 #70767
by djs14
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
Replied by djs14 on topic Open loop ok, no operation in Axis
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: 28 Feb 2016 21:01 by djs14.
Please Log in or Create an account to join the conversation.
28 Feb 2016 21:16 - 28 Feb 2016 21:16 #70769
by PCW
Replied by PCW on topic Open loop ok, no operation in Axis
Are you sure the commanded position is creeping?
( Axis's DRO shows the feedback position, not the commanded position )
( Axis's DRO shows the feedback position, not the commanded position )
Last edit: 28 Feb 2016 21:16 by PCW.
Please Log in or Create an account to join the conversation.
28 Feb 2016 21:58 #70774
by djs14
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.
Replied by djs14 on topic Open loop ok, no operation in Axis
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.
Please Log in or Create an account to join the conversation.
28 Feb 2016 22:02 #70775
by djs14
Replied by djs14 on topic Open loop ok, no operation in Axis
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.
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.
Please Log in or Create an account to join the conversation.
28 Feb 2016 22:44 - 28 Feb 2016 22:49 #70777
by djs14
Replied by djs14 on topic Open loop ok, no operation in Axis
Cmd-pos is following feedback in lock step.
There are no enable inputs on the drives. They are wired into limit switches which shut the drives down when triggered. And there are override buttons on the original operator panel that orverride the switches to jog off.
I'm mentioning this because I do no "enabling" of any outputs or halpins (that I'm aware of) related to drives. I guess this is all just happening in the background when I launch axis? edit: My thought process here being when does the control actually look at the current position and close the position loop to it? Do I have an error preventing this from happening?
I included some e-stop ladder when I was first putting things together and deleted those ladders. Did a variable get introduced somewhere that is related to e-stop or something? Sorry for the rambling post. Just trying to shed light on the problem.
There are no enable inputs on the drives. They are wired into limit switches which shut the drives down when triggered. And there are override buttons on the original operator panel that orverride the switches to jog off.
I'm mentioning this because I do no "enabling" of any outputs or halpins (that I'm aware of) related to drives. I guess this is all just happening in the background when I launch axis? edit: My thought process here being when does the control actually look at the current position and close the position loop to it? Do I have an error preventing this from happening?
I included some e-stop ladder when I was first putting things together and deleted those ladders. Did a variable get introduced somewhere that is related to e-stop or something? Sorry for the rambling post. Just trying to shed light on the problem.
Last edit: 28 Feb 2016 22:49 by djs14.
Please Log in or Create an account to join the conversation.
29 Feb 2016 00:03 #70785
by djs14
Replied by djs14 on topic Open loop ok, no operation in Axis
Are my pyvcp's with my classicladder tool changer holding things up?
My ladder is running looking at a pyvcp for a tool changer value for now. I will be calling that with an M6 command ultimately.
My ladder is running looking at a pyvcp for a tool changer value for now. I will be calling that with an M6 command ultimately.
Please Log in or Create an account to join the conversation.
29 Feb 2016 13:47 #70811
by andypugh
It may mean that you haven't turned the machine on?
You need to reset E-stop and then press the "machine on" button in Axis. (or press F1, F2)
Replied by andypugh on topic Open loop ok, no operation in Axis
The function boxes in the axis gui are grayed out/not clickable if that means anything..
It may mean that you haven't turned the machine on?
You need to reset E-stop and then press the "machine on" button in Axis. (or press F1, F2)
Please Log in or Create an account to join the conversation.
29 Feb 2016 15:05 #70815
by PCW
Replied by PCW on topic Open loop ok, no operation in Axis
Not having linuxcnc enable the drives is a safety issue
(a bad encoder connection/ drive /controller fault could lead to a undetected runaway)
I would get this fixed first
(this will also fix the drift since the drives will not be enabled until linuxcnc is in control)
(a bad encoder connection/ drive /controller fault could lead to a undetected runaway)
I would get this fixed first
(this will also fix the drift since the drives will not be enabled until linuxcnc is in control)
Please Log in or Create an account to join the conversation.
Time to create page: 0.103 seconds