Pause program on low air pressure
- alangibson
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15 Jul 2023 15:46 - 15 Jul 2023 15:47 #275515
by alangibson
Pause program on low air pressure was created by alangibson
I've got a friend that wants me to make a sign that needs more cutting than I think my small air compressor can supply in one go. I've been considering the idea of adding an air pressure sensor that would pause the program when the air drops below a usable level and resume the program when pressure is OK again.
I've got one of these sensors
www.amazon.de/-/en/pressure-sensor-stain...diesel/dp/B07YZL36FN
with this adapter
www.amazon.de/-/en/gp/product/B09MVZZBV3
My plan is to wire it up to my Mesa 7i96 then add roughly this non-working configuration. This is my first HAL config so go easy.
What do the experts think? Nice feature or bad idea?
I've got one of these sensors
www.amazon.de/-/en/pressure-sensor-stain...diesel/dp/B07YZL36FN
with this adapter
www.amazon.de/-/en/gp/product/B09MVZZBV3
My plan is to wire it up to my Mesa 7i96 then add roughly this non-working configuration. This is my first HAL config so go easy.
# Read in raw air sensor value
# https://linuxcnc.org/docs/html/man/man9/hostmot2.9.html
loadrt hostmot2
# load the component count equals how many you want
loadrt mult2 count=1
addf mult2.0 ???
# Set conversion factor to map from volts to pressure
# 3.45 to convert to bar, 50 to convert to PSI
# https://cdn.shopify.com/s/files/1/0043/6807/2822/files/200PSIRIFE_1024x1024.jpg?v=1662128648
setp mult2.0.in1 3.45
# Convert volts to pressure
# Read in raw air sensor value to multiplication component
net hm2_7i96.0.gpio.???.in => mult2.0.in0
# See if we should pause, resume, or do nothing using 2 comparators
loadrt comp count=2
addf comp ???
# comp out is true when in1 > in0
# Upper bound to resume program is 6 bar
setp comp.0.in1 mult2.0.out
setp comp.0.in0 6
# Lower bound to pause program is 4 bar
setp comp.1.in1 4
setp comp.1.in0 mult2.0.out
# Pause or resume program
net signal-air-pause halui.program.pause <= comp.1.out
net signal-air-resume halui.program.resume <= comp.0.outWhat do the experts think? Nice feature or bad idea?
Last edit: 15 Jul 2023 15:47 by alangibson.
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- tommylight
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15 Jul 2023 16:03 #275516
by tommylight
Replied by tommylight on topic Pause program on low air pressure
Seems that is an analog output sensor, Mesa 7i96 has no analog inputs.
Lets back off, every plasma source should have it's own pressure sensor, on smaller older ones it stops at 4bar, on older industrial Hypertherm it stops at 7 bar.
No idea if cheap ones have it, though.
PlasmaC and other plasma configs will stop the machine if the arc stops, hence no need for additional sensors.
If you still want to add that, an arduino nano will do just fine to sample the sensor voltage and trigger an output when the value gets out of range, that output can be wired to Mesa, and in hal to something like motion.inhibit, but there might be a better pin to use as after a stop the torch must also be stopped and on restart it has to do probing and firing.
Lets back off, every plasma source should have it's own pressure sensor, on smaller older ones it stops at 4bar, on older industrial Hypertherm it stops at 7 bar.
No idea if cheap ones have it, though.
PlasmaC and other plasma configs will stop the machine if the arc stops, hence no need for additional sensors.
If you still want to add that, an arduino nano will do just fine to sample the sensor voltage and trigger an output when the value gets out of range, that output can be wired to Mesa, and in hal to something like motion.inhibit, but there might be a better pin to use as after a stop the torch must also be stopped and on restart it has to do probing and firing.
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- chris@cnc
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15 Jul 2023 19:17 #275538
by chris@cnc
Replied by chris@cnc on topic Pause program on low air pressure
I would do it little easier. Use an adjustable sensor that only outputs true or false and connect to message. Maybe good to know why program stop.www.amazon.com/-/de/dp/B07RLJK6WT/ref=sr...89444139&sr=8-3&th=1
loadrt message names=airlow messages="Air Pressure low"
addf airlow servo-thread
net airlow <= hm2_7i96.0.gpio.???.in => airlow.trigger => halui.program.pausePlease Log in or Create an account to join the conversation.
- rodw
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16 Jul 2023 00:17 #275553
by rodw
Replied by rodw on topic Pause program on low air pressure
This will only be an issue if you are using a plasma cutter without an ArcOK (sometimes called transfer) output (As you are).
With the Everlast, hyperthermiam and thermal dynamics machines, low air pressure will drop the ArcOk signal.
QTplasmac will respond by pausing cutting. When air pressure is increased, ArcOK is restored and QTplasmac resumes cutting.
A simple solution would be to install a pressure switch used in 12/24 volt vehicle mounted compressors.
Example: bossairsuspension.com.au/shop/air-fittin...rZMmxUBoCX6YQAvD_BwE
With the Everlast, hyperthermiam and thermal dynamics machines, low air pressure will drop the ArcOk signal.
QTplasmac will respond by pausing cutting. When air pressure is increased, ArcOK is restored and QTplasmac resumes cutting.
A simple solution would be to install a pressure switch used in 12/24 volt vehicle mounted compressors.
Example: bossairsuspension.com.au/shop/air-fittin...rZMmxUBoCX6YQAvD_BwE
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- rodw
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16 Jul 2023 00:22 #275554
by rodw
Replied by rodw on topic Pause program on low air pressure
Further to that example, a 70-100 psi switch will turn on when pressure falls to 70 psi and turn off at 100 psi.
You can get different ranges. Say a 100-150 psi could work ok if the compressor cuts off at 130 psi as the off signal won't be reached and will come on at 100 psi. Mount it on the compressor side of any regulator you have for the plasma cutter. If it fired a relay that drops the ArcOK it would be done!
You can get different ranges. Say a 100-150 psi could work ok if the compressor cuts off at 130 psi as the off signal won't be reached and will come on at 100 psi. Mount it on the compressor side of any regulator you have for the plasma cutter. If it fired a relay that drops the ArcOK it would be done!
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- cmorley
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16 Jul 2023 05:40 #275564
by cmorley
Replied by cmorley on topic Pause program on low air pressure
linuxcnc.org/docs/2.9/html/config/core-c...html#sec:motion-pins
motion.feed-inhibit might be helpful.
motion.feed-inhibit might be helpful.
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