THC inactive after a reset

[offlanders]

I've been working on mostly small part on a pretty flat table for awhile, so I never noticed my THC wasn't working if I did a mid-job feed-hold or had to run back a few steps for whatever reason. I ran a few test cuts on a unlevel scrap piece to confirm. THC will work fine through the whole job as long as its not interrupted, but if you have a user interrupt it will not operate for the remainder of the job.

Is there a setting I'm missing or something I forgot to check?
Thanks,

[Joey]

Your not missing anything. If the THC is enabled in the profile manager than it will be enabled after a restart.

Possibly the THC enable button on the VCP was turned off?


Keep an eye on the THC enabled button on the VCP. That will let you know if the THC is enabled during the cut or not. During a restart you should see the THC enabled light light up when hitting cycle start to resume.

Are you currently running software version 5.06?

[offlanders]

I just did another test cut with a feed hold in the middle of a part purposely set unevenly. When I cycle-resumed the job the "THC Auto" light is lit on the virtual jog panel, the torch does a touch off for height then proceeds to cut but the THC doesn't raise or lower the head to contour the material and crashes the head (magnetic breakaway). Is there another place I should be looking for the THC to be in auto mode? I'm not sure this is relevant but I'm using my WMPG-6 from my Centroid acorn off my Milling machine.

I'm currently running version 5.06

[Joey]

Can you throw a report up. I should be able to see the report from that restart.

As long as the profile is set to Automatic THC and the VCP light is lit. THC should enable.

Anti dive may prevent the THC from reacting if the Voltage is high or the velocity isn't up to speed

[offlanders]

Here is the report file.

Looking at the THC settings I do not see anything remarkable. I did verify the 50:1 on the Hypertherm 65 Sync, and the THC settings in the software. The anti drive threshold is set to 7% does that need to be increased possibly?

[Joey]

Both Plots Look like the THC was working.

Can you turn the Pot to ON in the Utility menu and replicate a couple more restarts?

The Anti Dive threshold of 7% can be raised if the material is very on even or warping a lot.
But This will allow the THC to react to larger spikes in voltage. You can see the Antidive threshold in purple on the plot.
Notice the purple line kicks in and stops THC when the Yellow voltage line raises higher than 7% above the Light green Target voltage line.



The First Plot looks like a possible restart with a flame out.
The THC delay did not allow the THC to come on and by the time it did the torch was out.
Orange line shows THC turning on. The Yellow is the actual voltage and it shows that the torch was out by the time the orange THC line came on. The Red line is the THC offset counts. This is the THC Z path. You can see the torch raising due to low voltage when the torch turns on.

The second Plot looks like an interuption from having the THC ON when the XY Velocity was Low. The THC Config settings by default has a Anti-Dive Ratio of 90%. This means the THC will not enable if the XY velocity is below 90% of the Profiles XY Feedrate. It looks like from the Plot that this number was set closer to 45%. The Plot shows that the XY velocity slowing causes the kerf width to widen and there for raise the voltage since the ARC now travels further to reach new material. Allowing the THC to run at slower XY velocities will bring the torch down closer to the surface of the material.