Disable ohmic question

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repauli1
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Disable ohmic question

Post by repauli1 »

In the schematic 1508 it has ohmic wired thru an output. Is there an VCP button assigned to that output to allow enable/disable during cutting process?
TIA
Bob
ShawnM
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Re: Disable ohmic question

Post by ShawnM »

Hi Bob, I noticed this also when I was wiring up the machine. It goes through the normally closed side of the relay and I don't know if I've ever seen that relay activate. Maybe it is for a future enhancement or feature. You can add a button to the VCP to control that relay. Are you sure Centroid didn't do that for a reason? Not sure if a manual button would interfere with their design. Maybe Keith or Joey can chime in and fill us in on the "why".

What is your reason Bob for wanting to disable the ohmic sensor while cutting?
eng199
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Re: Disable ohmic question

Post by eng199 »

The relay protects the touch input from possible high negative voltage if a short to the input occurs during cutting. The relay will be removed in future versions. Please do not modify its operation.
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Re: Disable ohmic question

Post by repauli1 »

ShawnM wrote: Sun Jun 05, 2022 7:37 pm Hi Bob, I noticed this also when I was wiring up the machine. It goes through the normally closed side of the relay and I don't know if I've ever seen that relay activate. Maybe it is for a future enhancement or feature. You can add a button to the VCP to control that relay. Are you sure Centroid didn't do that for a reason? Not sure if a manual button would interfere with their design. Maybe Keith or Joey can chime in and fill us in on the "why".

What is your reason Bob for wanting to disable the ohmic sensor while cutting?
Prefer Float over Ohmic if metal is thick enough not to flex when floating head applies pressure. Ohmic is great but often touches water thus sensing incorrect material top.
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Re: Disable ohmic question

Post by ShawnM »

Yes, water is an issue with the ohmic sensor and a pain in the rear sometimes. I do keep the water level down about 1" from the top of the slats to keep splash down. This also helps with less dross but a little more smoke. I've seen some YouTube videos where guys have the water touching the bottom of the material they are cutting. I also have my PP raise the Z axis to the top when the job is complete to help with splash.

I prefer the ohmic sensor for the reason you mentioned, cutting thin material and not having it bend. I even slowed down my touch off rate to not deflect the thin sheet metal during a touch off. Just like with anything else there's always a trade off I guess.

Ohmic sensor versus floating head? I'll bet is gets the same response ratio as blonde versus brunette. :mrgreen:
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Re: Disable ohmic question

Post by jcoldon »

relay in thern for protection after torch fires it should open .
i run ohmic and float if i don't want ohmic i disconnect input it use float automatically . put ohmic back it use ohmic i install switch once i get a chance
i want try a ohmic unit first see if it better with the water. I have several models to try . acorn not true ohmic unit it uses gnd threw thc
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Re: Disable ohmic question

Post by AtomicAsian »

how do you set the z to move to top after job completed and move all axis to zero
ShawnM wrote: Mon Jun 06, 2022 10:36 am Yes, water is an issue with the ohmic sensor and a pain in the rear sometimes. I do keep the water level down about 1" from the top of the slats to keep splash down. This also helps with less dross but a little more smoke. I've seen some YouTube videos where guys have the water touching the bottom of the material they are cutting. I also have my PP raise the Z axis to the top when the job is complete to help with splash.

I prefer the ohmic sensor for the reason you mentioned, cutting thin material and not having it bend. I even slowed down my touch off rate to not deflect the thin sheet metal during a touch off. Just like with anything else there's always a trade off I guess.

Ohmic sensor versus floating head? I'll bet is gets the same response ratio as blonde versus brunette. :mrgreen:
ShawnM
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Re: Disable ohmic question

Post by ShawnM »

Don't let Keith see this post, he'll yell at you for doing this? :mrgreen:

I added a G53 move at the end of my post processor to move the Z axis to the home position. Those who use a water table will understand why. :o

I don't know what software you are using, I'm using Vectric software with my own custom PP for my machine.

Also, when you say "move to zero" do you mean machine zero or part zero?

You can do the same for the X and Y if you like but now the gantry is in the way for loading and unloading. I'm not sure of your machine size but on my larger 5x10 machine I have it move to the back of the table so can load and unload full sheets without the gantry being in the way. Then I use the "machine x0y0" button to return the gantry to the home position for the next job. Either way just add some simple code to the footer of your PP and define where you want the gantry to go.

I'm assuming you have the machine set up for "automatic homing" so the machine homes to your home switches, yes?
Last edited by ShawnM on Sat Jul 30, 2022 12:42 am, edited 2 times in total.
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Re: Disable ohmic question

Post by jcoldon »

run the new software if ohmic gets wet it just use float head. once it starts the air blow water out. the rest go back to ohmic . if i recall there setting to go home after finishing the job in sheet cam easy to add that in . unless not using sheet cam
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Re: Disable ohmic question

Post by AtomicAsian »

Yes he has got me once already. :lol: I am very new to this software very different from the mach 3 on my other table. this build is a koike 5x10 using sheetcam
I repeat part runs all day so i need it to zero at same spot
ShawnM wrote: Fri Jul 29, 2022 3:49 pm Don't let Keith see this post, he'll yell at you for doing this? :mrgreen:

I added a G53 move at the end of my post processor to move the Z axis to the home position. Those who use a water table will understand why. :o

I don't know what software you are using, I'm using Vectric software with my own custom PP for my machine.

You can do the same for the X and Y if you like but now the gantry is in the way for loading and unloading. I'm not sure of your machine size but on my larger 5x10 machine I have it move to the back of the table so can load and unload full sheets without the gantry being in the way. Then I use the "machine x0y0" button to return the gantry to the home position for the next job. Either way just add some simple code to the footer of your PP and define where you want the gantry to go.

I'm assuming you have the machine set up for "automatic homing" so the machine homes to your home switches, yes?
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