View Full Version : THC Min and Max not Native

12-01-2013, 01:50 AM
Just completed a Shopbot PRT Alpha conversion to Mach3 and CandCNC MP3000+DTHC for plasma use and thought I would share something I did not readily find in the documentation for Mach3 or CandCNC stuff.

The THC Min and Max are not set in native units but in the units of the part file.

Took me a long time to figure out why the THC was not working even though the Torch UP/DOWN signals were clearly being received and my THC Max was set to 1 and the Min set to -0.125 when my native units are in Inches. Cutting a metric part file would see the torch dive down to just below 1mm and then get stuck with the Torch UP indicator lit solid and volts on the DRO reading well below the specified. DOH!

Setting the Min to -2 and the Max to 25 made everything work great. Just have to remember to change it all back for those part files in inches.

01-13-2014, 07:20 PM
The THC MIN and MAX are not very useful with a the MP3000 & DTHC. The TIP SAVER will stop the diving and having small numbers in either setting can cause problems with cutting something outside those ranges. Our new stuff will cut corrugated at full horz speeds and you may touch off on a peak or valley and you may see negative numbers below -2.0" We have been setting the default Min and MAX to +1 and -1 (inches) for several years now and advise metric users to use +25 and -25
The DTHC IV no longer uses the THC logic in MACH so the settings for THC Rate , THC on/off or THC Corrections are no longer even used.