Dual X Servo
28 Apr 2013 05:23 #33300
by juwi
Dual X Servo was created by juwi
Hi
www.linuxcnc.org/index.php/english/forum...in-closed-loop#23714
Andy told me "simply" to:
"connect axis.1.motor-pos-cmd to both PID modules in the HAL"
How is this done? If I just change:
net a-pos-cmd axis.3.motor-pos-cmd
to
net a-pos-cmd axis.1.motor-pos-cmd
There comes an "net already connected" error on Startup...
HAL File is attached, INI too, A axis is second Y axis
Help?
best regards
www.linuxcnc.org/index.php/english/forum...in-closed-loop#23714
Andy told me "simply" to:
"connect axis.1.motor-pos-cmd to both PID modules in the HAL"
How is this done? If I just change:
net a-pos-cmd axis.3.motor-pos-cmd
to
net a-pos-cmd axis.1.motor-pos-cmd
There comes an "net already connected" error on Startup...
HAL File is attached, INI too, A axis is second Y axis
Help?
best regards
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28 Apr 2013 05:52 - 28 Apr 2013 05:52 #33301
by juwi
Replied by juwi on topic Dual X Servo
michas_kleine.hal:164: Signal 'y-pos-cmd' can not add OUT pin 'axis.3.motor-pos-cmd', it already has OUT pin 'axis.1.motor-pos-cmd'
Last edit: 28 Apr 2013 05:52 by juwi.
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28 Apr 2013 07:27 #33308
by andypugh
I just tried to make your HAL file work as suggested, and I have realised that it is rather important to know if you intend to use index-homing on both sides of the gantry.
I think I need to have a good long think about how to do homing on a gantry axis that uses servos and trivkins.
Replied by andypugh on topic Dual X Servo
Hi
www.linuxcnc.org/index.php/english/forum...in-closed-loop#23714
Andy told me "simply" to:
"connect axis.1.motor-pos-cmd to both PID modules in the HAL"
How is this done?
I just tried to make your HAL file work as suggested, and I have realised that it is rather important to know if you intend to use index-homing on both sides of the gantry.
I think I need to have a good long think about how to do homing on a gantry axis that uses servos and trivkins.
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28 Apr 2013 07:30 #33309
by andypugh
Replied by andypugh on topic Dual X Servo
This is the HAL file I came up with, but I can't really test it.
The main point is that the HAL is now assuming a 3-axis machine, but with 4 PID controllers and 4 motors to drive.
The main point is that the HAL is now assuming a 3-axis machine, but with 4 PID controllers and 4 motors to drive.
The following user(s) said Thank You: juwi
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28 Apr 2013 07:53 #33311
by juwi
Replied by juwi on topic Dual X Servo
michas_kleine.hal:111: Pin 'axis.0.motor-pos-cmd' was already linked to signal 'x1-pos-cmd'
exactly my problem...
exactly my problem...
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28 Apr 2013 08:25 #33312
by juwi
Homing is almost irrelevant, because I can home the machine by hand - its quite small - or by a special homing config with gantrykins...
My Problem is that hal forbids to add more than one outs to a net...
best regards
Replied by juwi on topic Dual X Servo
Hi
www.linuxcnc.org/index.php/english/forum...in-closed-loop#23714
Andy told me "simply" to:
"connect axis.1.motor-pos-cmd to both PID modules in the HAL"
How is this done?
I just tried to make your HAL file work as suggested, and I have realised that it is rather important to know if you intend to use index-homing on both sides of the gantry.
I think I need to have a good long think about how to do homing on a gantry axis that uses servos and trivkins.
Homing is almost irrelevant, because I can home the machine by hand - its quite small - or by a special homing config with gantrykins...
My Problem is that hal forbids to add more than one outs to a net...
best regards
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28 Apr 2013 19:03 #33323
by andypugh
Replied by andypugh on topic Dual X Servo
My Problem is that hal forbids to add more than one outs to a net...
Yes, only one of the pins in the net can be an output (such as axis.0.motor-pos-cmd). This is logical, as otherwise the value of the net is ambiguous.
To use one output to drive multiple inputs you can use any of the following structures.
net x-pos axis.0.motor-pos-cmd => pid.0.command pid.1.command
or
net x-pos axis.0.motor-pos-cmd=> pid.0.command
net x-pos pid.1.command
or
net x-pos axis.0.motor-pos-cmd
net x-pos pid.0.command
net x-pos pid.1.command
So, each signal (the label directly after the "net" command) can have only one output pin connected, but can have as many input pins as you need.
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28 Apr 2013 19:07 #33324
by juwi
Replied by juwi on topic Dual X Servo
This works, but leads to a following error on the slave axis after exceeding max-ferror...
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28 Apr 2013 19:12 #33325
by andypugh
Replied by andypugh on topic Dual X Servo
If the motors point in different directions then you will need a negative encoder scale on one of them.
Each PID component needs to be connected to the same command position pin, but to its own feedback position pin.
Each PID component needs to be connected to the same command position pin, but to its own feedback position pin.
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28 Apr 2013 19:26 #33327
by juwi
Replied by juwi on topic Dual X Servo
I write on my mobile, therefore short...
I left everything of the slave axis as it was, just connect the pid.commanded from y.pos to both. Result is following error after exceeding fferror-max.
Both are setup identical and rotate in the same direction...
I left everything of the slave axis as it was, just connect the pid.commanded from y.pos to both. Result is following error after exceeding fferror-max.
Both are setup identical and rotate in the same direction...
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