- Configuring LinuxCNC
- Advanced Configuration
- Robot reads the same position every time it is turned on.
Robot reads the same position every time it is turned on.
- hellvetica
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26 Jun 2025 12:53 #330891
by hellvetica
Robot reads the same position every time it is turned on. was created by hellvetica
Hi, I have a delta robot built on ethercat and running linuxcnc.
We recently got drives with absolute encoders so i had to make a specific homing procedure that just triggers the internal homing on the drives.
The drives then reset their encoder positions internally to 0 or home offset if it's set in HAL with lcec.
Then, when using the robot i could move it somewhere, turn off linux cnc and then start it again and linuxcnc always shows the same position when starting [ 0. , 0. , -496.22474747]. When i disable the home offset this number still stays the same. I move the robot to [0,0,-700], restart and it still shows the same position, and then moves "ignoring" the soft limits. The encoders themselves retain their position information properly, it's just linuxcnc that reads it wrong (or doesn't read it for some reason) What am i missing here?
Here are the files for my config.
We recently got drives with absolute encoders so i had to make a specific homing procedure that just triggers the internal homing on the drives.
The drives then reset their encoder positions internally to 0 or home offset if it's set in HAL with lcec.
Then, when using the robot i could move it somewhere, turn off linux cnc and then start it again and linuxcnc always shows the same position when starting [ 0. , 0. , -496.22474747]. When i disable the home offset this number still stays the same. I move the robot to [0,0,-700], restart and it still shows the same position, and then moves "ignoring" the soft limits. The encoders themselves retain their position information properly, it's just linuxcnc that reads it wrong (or doesn't read it for some reason) What am i missing here?
Here are the files for my config.
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- hellvetica
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26 Jun 2025 13:18 #330892
by hellvetica
Replied by hellvetica on topic Robot reads the same position every time it is turned on.
I just noticed that halui.axis.x.pos-relative read the value correctly and it retains it after restart. The axis.x.pos-cmd always starts at -496.2247. When i move the robot the halui.axis.x.pos-relative reports the correct absolute position but the robot moves as if it has been started at -496.2247. Any ideas?
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- meister
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26 Jun 2025 13:43 #330894
by meister
Replied by meister on topic Robot reads the same position every time it is turned on.
I would try to remove the PARAMETER_FILE (sim_mm.var) and then start the program
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- hellvetica
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26 Jun 2025 14:13 #330895
by hellvetica
Replied by hellvetica on topic Robot reads the same position every time it is turned on.
Thanks for the reply.
I removed it but it had no effect.
I removed it but it had no effect.
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- Aciera
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26 Jun 2025 15:07 #330897
by Aciera
Replied by Aciera on topic Robot reads the same position every time it is turned on.
Post your custom homing procedure please.
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- Configuring LinuxCNC
- Advanced Configuration
- Robot reads the same position every time it is turned on.
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