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View Full Version : THC settings explanation - Clear as MUD!



Wolfesmetalfab
04-11-2010, 08:49 PM
I am wanting to clear up some confusion I have about some settings and readings. First off with the "Max THC" and "Min THC" under Corrections

So what is a normal setting? Max is almost clear to me (I think). If it is set at .75, then it will allow it to rise up 3/4". But is this from were it starts at cut height (we will say .0625"), or from top of material zero?

So what about "MIN THC"? This one is clear as mud to me. If it is at .25, then does that allow it to lower 1/4" from pierce height, or cut height? Or is the minimum amount of correction it will make is 1/4" (dont think so) Or is 1/4" above the material zero, the lowest it will go? (which wouldn't be good because cut height is supposed to be .0625.

it seems to work with it set at .75 max, and .2 min, but I want to know what I am setting.

Just trying to clear up some confusion.

Thanks in advance guys

Torchhead
04-14-2010, 10:39 AM
All Z measurements are from Z zero (Top of Material). Since that changes as the material wraps and moves from cutting, you have to reestablish Z zero often while cutting (before a pierce move) THC Corrections just prevents the Z from moving past preset limits. Min should be the lowest you will let the Z go while cutting. If you touch-off and reference on a high spot then proceed to cut to a lower spot and you have the MIN set to .2 then it won't follow the material down. The MIN should be 0 or perhaps even slightly negative. I set mine to -.125 for most cutting. It's just a failsafe so if you were to plunge off the side of the material, the Z would drive down as far as Z would go and possibly hit a grid bar and snap off the end of the torch. It's less concern on THC's that have the Dynamic anti-dive like the MP3000-DTHC and as I understand, the THC301D. The anti-dive would sense the voltage spike from the open cut and lock Down Movement. We have that as one of the CUT PROFILE parameters as a percentage of preset volts and is adjustable by the user. We found the number needs to change for thicker material.

TOM caudle
www.CandCNC.com
Totally Modular CNC Electronics.

Wolfesmetalfab
04-18-2010, 03:41 PM
Tom, that was an excellent description, it totally answered my min/max THC questions, makes sense, i just needed to verify how it was done.

For Anti Dive, it has a setting which is currently at +60. Could you explain that a bit more? I know it senses for extreme changes like running off the material, or slowing and making a turn at a corner, but how do i base what I want the setting at for say 1/8" or 1/4" steel? Just looking for another one of your great descriptions.

Also on the Settings tab, i have a lable "Tip Volts" with a button "THC Table" (were you can save and load settings evidently), it currently says +40....

What is that for?

And below that says THC Delay +1.0 (i am assuming it waits either 1 inch or 1 second after a pierce before kicking in the THC because of pierce voltage variations?

Is that all the settings for THC?

Thanks in advance for your knowledge and help, i just like to understand what i am doing and the settings associated with it.

Brian =)