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limit and home switch
04 Dec 2014 00:30 #53641
by gaeldk
Replied by gaeldk on topic limit and home switch
Thanks both for your answers, really appreciate the help.
I don't fully get your suggestion.
The desired behavior is that when I home :
STEP 1) My machines moves slowly towards the combined home/limit switch - which is OK now
STEP 2) the machine stops when the limit switch fires and gets ready to move in the opposite direction. Eventually even better it could clear off the home/limit switch by itself
Right now it does STEP1 but then I get a limit switch error and can not use the machine without disabling the limits... which is not practical and a bit dangerous
My INI file looks like below for the Z axis (which is my test axis), I will replicate on the others after I am successful getting the right behavior on Z.
As you can see HOME_IGNORE_LIMITS is set so I don't get what the issue is and why the error blocks everything in AxisGUI.
I am on LinuxCNC 2.6.4
I don't fully get your suggestion.
The desired behavior is that when I home :
STEP 1) My machines moves slowly towards the combined home/limit switch - which is OK now
STEP 2) the machine stops when the limit switch fires and gets ready to move in the opposite direction. Eventually even better it could clear off the home/limit switch by itself
Right now it does STEP1 but then I get a limit switch error and can not use the machine without disabling the limits... which is not practical and a bit dangerous
My INI file looks like below for the Z axis (which is my test axis), I will replicate on the others after I am successful getting the right behavior on Z.
[AXIS_2]
TYPE = LINEAR
HOME = 0.0
MAX_VELOCITY = 35.0
MAX_ACCELERATION = 130.0
STEPGEN_MAXACCEL = 162.5
SCALE = 160.0
FERROR = 1
MIN_FERROR = .25
MIN_LIMIT = -280.0
MAX_LIMIT = 0.001
HOME_OFFSET = 0.000000
HOME_SEARCH_VEL = 0.050000
HOME_LATCH_VEL = 0.050000
HOME_IGNORE_LIMITS = YESAs you can see HOME_IGNORE_LIMITS is set so I don't get what the issue is and why the error blocks everything in AxisGUI.
I am on LinuxCNC 2.6.4
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04 Dec 2014 01:16 #53646
by gaeldk
Replied by gaeldk on topic limit and home switch
Thanks guys,
But unfortunately another problem showed up
In the homing procedure of Z axis, after max_home_z signal has been set to TRUE by reaching the switch (I use the HAL METER to check), the machine moves down as it should and clears from the switch BUT the signal never goes back to FALSE. So the Z keeps going down trying to clear from the switch although it already did...
If I stop and restart Axis (without doing anything to the machine) and then use the HAL METER again then the max_home_z signal is FALSE as it should be ...
What could be the reason for the signal not to be properly refreshed after it fired ?
But unfortunately another problem showed up
In the homing procedure of Z axis, after max_home_z signal has been set to TRUE by reaching the switch (I use the HAL METER to check), the machine moves down as it should and clears from the switch BUT the signal never goes back to FALSE. So the Z keeps going down trying to clear from the switch although it already did...
If I stop and restart Axis (without doing anything to the machine) and then use the HAL METER again then the max_home_z signal is FALSE as it should be ...
What could be the reason for the signal not to be properly refreshed after it fired ?
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04 Dec 2014 19:13 #53680
by gaeldk
Replied by gaeldk on topic limit and home switch
Hello,
Spent all evening yesterday and this morning checking all the wires with a multimeter and pocket digital probe... all ok on the machine...
Then in a last minute desperate move, I changed PC, did not change the // cable just changed PC... to an older machine in my garage running the same debian wheezy linuxcnc (athlon X2, about 10 years old) and then...
it WORKS !
The switch probe properly switches back to FALSE when moving of the sensor....
So the problem is with the brand new PC I just got ! I talked a bit about this new PC in the thread : HERE
But the config is :
Debian Wheezy Xfce / Kernel 3.4-9-rtai-686-pae
So my conf is Q1900M
Intel Speedstep : Disabled
CPU C States support : Disabled
Ehanced Halt state (C1E) : Disabled
No Execute Mem protection : enabled
Intel Virtualization : disabled
IGPU : Enabled
Onboard HD audio : Disabled
Deep S5 : Disabled
PCIE1 Link speed : auto
any idea why the parallel port would misbehave on this small computer ?
thanks
Spent all evening yesterday and this morning checking all the wires with a multimeter and pocket digital probe... all ok on the machine...
Then in a last minute desperate move, I changed PC, did not change the // cable just changed PC... to an older machine in my garage running the same debian wheezy linuxcnc (athlon X2, about 10 years old) and then...
it WORKS !
The switch probe properly switches back to FALSE when moving of the sensor....So the problem is with the brand new PC I just got ! I talked a bit about this new PC in the thread : HERE
But the config is :
Debian Wheezy Xfce / Kernel 3.4-9-rtai-686-pae
So my conf is Q1900M
Intel Speedstep : Disabled
CPU C States support : Disabled
Ehanced Halt state (C1E) : Disabled
No Execute Mem protection : enabled
Intel Virtualization : disabled
IGPU : Enabled
Onboard HD audio : Disabled
Deep S5 : Disabled
PCIE1 Link speed : auto
any idea why the parallel port would misbehave on this small computer ?
thanks
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04 Dec 2014 21:13 #53683
by andypugh
It might be due to pull-up / pull-down config of the pins.
How is the switch wired? Typically you only need to connect the pin to gnd with a switch, and it is high with the switch open and low with it closed.
However, it is possible you might need a pull-up to 5V to make that work.
If you have the switch wired to 5V through a switch then try the alternative wiring.
The old PC is probably a 5V p-port and the new one is probably 3.3V. This shouldn't matter when using switch-to-gnd and GPIO.
If you can't make it work then you have the perfect excuse to switch to something better than a parallel port
Replied by andypugh on topic limit and home switch
any idea why the parallel port would misbehave on this small computer ?
It might be due to pull-up / pull-down config of the pins.
How is the switch wired? Typically you only need to connect the pin to gnd with a switch, and it is high with the switch open and low with it closed.
However, it is possible you might need a pull-up to 5V to make that work.
If you have the switch wired to 5V through a switch then try the alternative wiring.
The old PC is probably a 5V p-port and the new one is probably 3.3V. This shouldn't matter when using switch-to-gnd and GPIO.
If you can't make it work then you have the perfect excuse to switch to something better than a parallel port
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