torch nose dives every time

[14u2cnc]

First thank you for anyone who can help.

I purchased a used LDR Table with mach 3 and sheetcam with hyp 85, would like to try and make this program work because upgrading cost is huge I just found out....

I can run lines all day with NO THC
I have done all the test imaginable to see if there is a com problem or volt problem ...everything checks out in that dept ie, Arc OK and volt test
My hub firmware is 1.6

As soon as I turn THC ON and hit run the torch touches off fires and drives itself into the table.....

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I just found thru more reading that the THC MODE did not have a check mark in the box on General Config Page. I checked the box and restarted the program per instruction...
Now when I do a Check Z switch offset....the torch fires for some reason?....

Anyone with pictures of their settings page might help. Thank you...I see the THC doesnt have green check marks or ports assigned???

[weldguy]

If you do a straight line test cut at the appropriate cut height and measure the arc voltage at the controller input what does it read?

[14u2cnc]

I have hyp 85 set to 45 amps
45 amp consumables are correct
My 10 inch line is set to 171 ipm, 133 volts and 12g steel as well as thc set to 1 in sheetcam...
With THC off on Mach 3 screen, I run a straight line test and the torch touches off, fires and cuts with volts reading on the mach 3 screen as 133-135

When I do the same exact thing with the THC ON ...it touches off fires torch and nose dives into plate and doesnt move.

When you measure arc voltage at Controller input....what procedure would I perform for that test? and how? Thank you for your reply...

[14u2cnc]

These are what the screen read on my setup.
I purchased this machine used
Previous owner told me computer was messed up
This LDR table came with Router and scrib attachment

And me thinking I could fix this mess on my own...

Thank you for any help

[dhelfter]

The only reason the torch will dive is the preset volts is lower than actual. There are a number of things that can cause this.
I would check
The thc direction is correct
Close all programs, up the hub admin program the click setup and test. Using on screen arrows move z axis and verify the torch goes the correct way. Also check the steps per are exactly the same as it is set in mach3

Verify pierce delay is set to book specs

Verify thc delay is at least 1 second

Check the thc tuning.
I recommend top slider is set to 16
Second slider is set to 4
Tracking to 1 volt

Dan
Ldr

[14u2cnc]

Reviewed your reply and followed instructions to a T....toggle up and down Z axis no issue

Still no change...Run, torch touches off, fires torch, nose dives

No THC it cuts 10 inch line consistent reads approx 133V plus or minus one volt (PMX85,new 45amp consumables)

I attached pictures in case something catches an eye...

Thank you

[14u2cnc]

The Plasma tool setting

[dhelfter]

Run your test line with thc on, and video the screen (not the torch)
send to my email
Dan

[tcaudle]

If you do the test with the DTHC off and the Torch volts displays close to the preset volts number then it sounds like maybe you have the Z DIR in the DTHC settings wrong. The Fast Jog buttons havee to match the direction they say . The DRO readinsg should INCREASE as you go up and decrease as you go down. Make sure you are using the correct consumables for the 45A cut on 12G you show. The DTHC tries to lower the torch volts to match the Preset (target) voltage. Get a baseline voltage with it off and if its close flip it on in the cut. If it dives then something is set wrong in the DTHC .

[14u2cnc]

At the direction of Dan from LDR I reinstalled the entire system and it resolved all of the THC issues.
Awesome table and awsome support from Dan@LDR