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- MPG working with joint but not with axis ???
MPG working with joint but not with axis ???
17 Aug 2022 01:18 #249925
by JPL
Replied by JPL on topic MPG working with joint but not with axis ???
Mystery Solved!!!
The reason why the MPG was not working with 'axis.x' is simply because ALL the axis should be homed before that. Not just the single axis controlled by the MPG. I did not realized that on my (lathe) config since I had only one motor connected for the x axis and did not even tried to home the z axis because of that.
More specifically it appears that jogging axis is allowed only in teleop mode while jogging joints is only allowed in Joint-mode (aka Free mode)...
But this, for example, will allow jogging in both mode: (although not recommended)
setp axis.x.jog-vel-mode 0
net x-jog-enable => axis.x.jog-enable
net x-jog-count => axis.x.jog-counts
net selected-jog-incr => axis.x.jog-scale
net x-jog-enable => joint.0.jog-enable
net x-jog-count => joint.0.jog-counts
net selected-jog-incr => joint.0.jog-scale
sets x-jog-enable true
sets selected-jog-incr 1.00000
The reason why the MPG was not working with 'axis.x' is simply because ALL the axis should be homed before that. Not just the single axis controlled by the MPG. I did not realized that on my (lathe) config since I had only one motor connected for the x axis and did not even tried to home the z axis because of that.
More specifically it appears that jogging axis is allowed only in teleop mode while jogging joints is only allowed in Joint-mode (aka Free mode)...
But this, for example, will allow jogging in both mode: (although not recommended)
setp axis.x.jog-vel-mode 0
net x-jog-enable => axis.x.jog-enable
net x-jog-count => axis.x.jog-counts
net selected-jog-incr => axis.x.jog-scale
net x-jog-enable => joint.0.jog-enable
net x-jog-count => joint.0.jog-counts
net selected-jog-incr => joint.0.jog-scale
sets x-jog-enable true
sets selected-jog-incr 1.00000
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17 Aug 2022 01:28 #249926
by JPL
Replied by JPL on topic MPG working with joint but not with axis ??? [solved]
Aka Rod was rightI think all axes likely need homing before your MPG is used..
The following user(s) said Thank You: rodw
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17 Aug 2022 02:54 #249928
by cmorley
Replied by cmorley on topic MPG working with joint but not with axis ??? [solved]
Ahh that what Rod mentioned.
What do you meN nor recommended?
I am surprised pncconf did not connect Hal in that way actually.
What do you meN nor recommended?
I am surprised pncconf did not connect Hal in that way actually.
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17 Aug 2022 19:28 #249968
by JPL
Replied by JPL on topic MPG working with joint but not with axis ??? [solved]
AFAIK most (if not all) industrial robots do not allow jogging before homing all the axes. I have an older Adept cartesian robot as well as a Yamaha cartesian robot and neither of them allow any motion before homing.
I can see a few reasons why:
- The position is unknown before homing (except with absolute encoders). Software limits are then useless, DRO is then useless too. Limit switches may not work if you're past the detection point.
- With gantry machine, or any machine with more than one joint per axes, problems may happen if a single joint is moved (ex racking)
- With a correct homing procedure there is simply no need for jogging before homing and in fact LinuxCnc has everything needed for that.
I can see a few reasons why:
- The position is unknown before homing (except with absolute encoders). Software limits are then useless, DRO is then useless too. Limit switches may not work if you're past the detection point.
- With gantry machine, or any machine with more than one joint per axes, problems may happen if a single joint is moved (ex racking)
- With a correct homing procedure there is simply no need for jogging before homing and in fact LinuxCnc has everything needed for that.
The following user(s) said Thank You: rodw
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- sprintertrd
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18 Aug 2022 06:23 #249999
by sprintertrd
Replied by sprintertrd on topic MPG working with joint but not with axis ??? [solved]
Interesting, I have a old CNC mill that allows axis jogging before homing and does not have absolute encoders. You can even set a 0 XYZ work position run G code but at a reduced maximum feed rate.
I would guess that on initial setup of the mill the home positions are set, the XYZ travels are hard coded in the software and from there on the position of the axis are saved in memory. If it is turned off it knows where it is on the next power-up.
I would guess that on initial setup of the mill the home positions are set, the XYZ travels are hard coded in the software and from there on the position of the axis are saved in memory. If it is turned off it knows where it is on the next power-up.
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09 Jan 2024 20:32 #290298
by JT
JT
Replied by JT on topic MPG working with joint but not with axis ???
I was just restoring my BP after a PC crash and found this thread with google and you saved me from pulling my hair out.That allows you to jog In joint mode before homing.
You must home to jog as an axis.
JT
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- Configuring LinuxCNC
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- MPG working with joint but not with axis ???
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