What kind of homeswitch do i need?
- Holzwurm56
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31 Dec 2016 15:24 #84960
by Holzwurm56
What kind of homeswitch do i need? was created by Holzwurm56
Hello,
I want to retrofit my wood milling machine with a Mesa 5I25 and 7I77. What kind of home switch is possible? A normaly open or normaly closed? Can i select this in the configuration, or is only one of these kinds possible?
Thanks
Hans
I want to retrofit my wood milling machine with a Mesa 5I25 and 7I77. What kind of home switch is possible? A normaly open or normaly closed? Can i select this in the configuration, or is only one of these kinds possible?
Thanks
Hans
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31 Dec 2016 16:31 - 31 Dec 2016 16:31 #84966
by PCW
Replied by PCW on topic What kind of homeswitch do i need?
Normally closed switches are generally a bit safer for limits and home switch use
since a broken wire/open switch will be detected
If you use normally closed limit/home switches with a 7I77, you wire them like this:
+24V --> limit/home switch --> 7I77 digital input
and you connect the inverted input pin (ends in -not) to the hal limit or home signal
in the hal file
since a broken wire/open switch will be detected
If you use normally closed limit/home switches with a 7I77, you wire them like this:
+24V --> limit/home switch --> 7I77 digital input
and you connect the inverted input pin (ends in -not) to the hal limit or home signal
in the hal file
Last edit: 31 Dec 2016 16:31 by PCW.
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01 Jan 2017 16:40 #85018
by dannym
Replied by dannym on topic What kind of homeswitch do i need?
I do prefer the inductive prox switches, they can't get dirty. But many do have problematic output logic levels that require some conditioning.
Recommend combining with a hard stop, you don't want it to be physically possible to run the axis off the rails.
Make it so your switch won't get smashed if it continues to move. It will overshoot a bit due to deceleration times.
Recommend combining with a hard stop, you don't want it to be physically possible to run the axis off the rails.
Make it so your switch won't get smashed if it continues to move. It will overshoot a bit due to deceleration times.
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01 Jan 2017 16:52 - 01 Jan 2017 16:53 #85020
by Holzwurm56
Replied by Holzwurm56 on topic What kind of homeswitch do i need?
Hello,
many thanks for your answers. On my machine are mechanical switches installed, at first i will use them. I can wire them as NO or NC. When these are not exact enough i can use the indeximpuls from the encoder additional.
Hans
many thanks for your answers. On my machine are mechanical switches installed, at first i will use them. I can wire them as NO or NC. When these are not exact enough i can use the indeximpuls from the encoder additional.
Hans
Last edit: 01 Jan 2017 16:53 by Holzwurm56.
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05 Jan 2017 13:29 - 05 Jan 2017 13:32 #85284
by Holzwurm56
Replied by Holzwurm56 on topic What kind of homeswitch do i need?
Hello,
i make some work on my cnc. Encoder scale = O.K., Encoder count direction = O.K., avis moving direction = O. K., moving with keyboard arrows = O.K.. I connected my x/y/z home switch as normally closed= +24V > homeswitch > 7i77(pin16/17/18).
The reference moving works not correct. The homeswitch is not found.
Hal file:
net home-x <= hm2_5i25.0.7i77.0.0.input-16
net home-x => axis.0.home-sw-in-not(without -not LinuxCNC starts but the referencepoint isn't find)
Error message:
./BIMA600.hal:88:Pin'axis.0.home-sw-in-not' does not exist 6727
Shows the window LinuxCncStatus the pinstatus the real pinstatus? Can i see there the real status of the home swtich? Change the display between 0 and 1 when i push the homeswitch? In my case the pins are with the normally closed switch connected to 24V, but window shows for these pins allways zero.
Thanks
Hans
i make some work on my cnc. Encoder scale = O.K., Encoder count direction = O.K., avis moving direction = O. K., moving with keyboard arrows = O.K.. I connected my x/y/z home switch as normally closed= +24V > homeswitch > 7i77(pin16/17/18).
The reference moving works not correct. The homeswitch is not found.
Hal file:
net home-x <= hm2_5i25.0.7i77.0.0.input-16
net home-x => axis.0.home-sw-in-not(without -not LinuxCNC starts but the referencepoint isn't find)
Error message:
./BIMA600.hal:88:Pin'axis.0.home-sw-in-not' does not exist 6727
Shows the window LinuxCncStatus the pinstatus the real pinstatus? Can i see there the real status of the home swtich? Change the display between 0 and 1 when i push the homeswitch? In my case the pins are with the normally closed switch connected to 24V, but window shows for these pins allways zero.
Thanks
Hans
Last edit: 05 Jan 2017 13:32 by Holzwurm56.
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05 Jan 2017 14:09 - 05 Jan 2017 14:11 #85285
by PCW
Replied by PCW on topic What kind of homeswitch do i need?
You probably want:
net home-x <= hm2_5i25.0.7i77.0.0.input-16-not
net home-x => axis.0.home-sw-in
There is no axis.0.home-sw-in-not (as you found out)
You can show all the available pins with:
halcmd show pin
When linuxCNC is running.
You can also show the state of the pins with the Axis menu:
Machine --> Show Hal Configuration --> Watch --> (select the pin or parameter to watch)
net home-x <= hm2_5i25.0.7i77.0.0.input-16-not
net home-x => axis.0.home-sw-in
There is no axis.0.home-sw-in-not (as you found out)
You can show all the available pins with:
halcmd show pin
When linuxCNC is running.
You can also show the state of the pins with the Axis menu:
Machine --> Show Hal Configuration --> Watch --> (select the pin or parameter to watch)
Last edit: 05 Jan 2017 14:11 by PCW.
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09 Jan 2017 11:26 #85510
by Holzwurm56
Replied by Holzwurm56 on topic What kind of homeswitch do i need?
Hello,
my homeswitch is normally closed. Wiring = +24V > homeswitchNC > inputpin 7i77.
With halscope i can see that the homeswitches are working correct.
Entry hal-file: net home-x <= hm2_5i25.0.7i77.0.0.input-00-not
net home-x <= hm2_5i25.0.7i77.0.0.input-01-not
net home-x <= hm2_5i25.0.7i77.0.0.input-02-not
When starting the homeseqence the axis move in the correct direction. When the homeswitch opens
there is the following message: "Home switch inactive before start of latch move" and the homingsequence is abort.
Does someone knows what do i wrong?
Thanks
Hans
my homeswitch is normally closed. Wiring = +24V > homeswitchNC > inputpin 7i77.
With halscope i can see that the homeswitches are working correct.
Entry hal-file: net home-x <= hm2_5i25.0.7i77.0.0.input-00-not
net home-x <= hm2_5i25.0.7i77.0.0.input-01-not
net home-x <= hm2_5i25.0.7i77.0.0.input-02-not
When starting the homeseqence the axis move in the correct direction. When the homeswitch opens
there is the following message: "Home switch inactive before start of latch move" and the homingsequence is abort.
Does someone knows what do i wrong?
Thanks
Hans
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09 Jan 2017 17:06 #85526
by PCW
Replied by PCW on topic What kind of homeswitch do i need?
sounds like ether the motion overan the home switch when decelerating or you
have enough contact bounce that you need to de-bounce the home switch signals
have enough contact bounce that you need to de-bounce the home switch signals
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09 Jan 2017 21:51 #85548
by Holzwurm56
Replied by Holzwurm56 on topic What kind of homeswitch do i need?
Hello PCW,
when I start the homing sequence the axis move in the normally closed homeswitch and the switch opens so its inactive( no more 24V on the inputpin ). My opinion is that linuxcnc had to know that in this case the swiching point is when the homeswitch toggles to active.
Or is the correct homing sequence only possible with a normally open switch?
Thanks
Hans
when I start the homing sequence the axis move in the normally closed homeswitch and the switch opens so its inactive( no more 24V on the inputpin ). My opinion is that linuxcnc had to know that in this case the swiching point is when the homeswitch toggles to active.
Or is the correct homing sequence only possible with a normally open switch?
Thanks
Hans
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09 Jan 2017 22:23 - 09 Jan 2017 22:24 #85549
by PCW
Replied by PCW on topic What kind of homeswitch do i need?
Any switch type is usable if the correct polarities are used, NC switches are preferred
for limit and home switches since a broken wire will usually cause a fault rather than a crash
As far as LinuxCNC is concerned, the homing starts with the home switch inactive
( The 7I77 xxxxx-not pin will be inactive until the switch is tripped )
Once the home switch is tripped LinuxCNC starts decelerating to 0 speed and then
makes the latch move to determine the final home position. It expects that the switch is still tripped
at this point, but it seems to be no longer active (the xxx-not pin is low)
This is why I asked if the switch had been overrun (this might happen because your acceleration values are too low
or the homing speed is too high or both)
for limit and home switches since a broken wire will usually cause a fault rather than a crash
As far as LinuxCNC is concerned, the homing starts with the home switch inactive
( The 7I77 xxxxx-not pin will be inactive until the switch is tripped )
Once the home switch is tripped LinuxCNC starts decelerating to 0 speed and then
makes the latch move to determine the final home position. It expects that the switch is still tripped
at this point, but it seems to be no longer active (the xxx-not pin is low)
This is why I asked if the switch had been overrun (this might happen because your acceleration values are too low
or the homing speed is too high or both)
Last edit: 09 Jan 2017 22:24 by PCW.
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