Hi there,
I am using Mach (latest stable V3) on a 5x10' plasma table with CandCNC electronics and torch height control.  I'm using the CandCNC screenset.  I'm having a really irritating problem where after a feedhold/resume, the z axis (torch height), which previously wasn't moving, immediately upon resuming, will start creeping higher.  It will continue this behavior until the end of the current straight line (or maybe G code instruction?).  Once it hits the next corner, it stops raising the Z, continuing on as normal, with the Z at the height where it was when it hit the corner.

I don't think this is a THC problem, because it does it with the DTHC turned off, as well as on.  If the DTHC is on, sometimes after resuming the torch will start coming up because of this bug, but the DTHC will grab hold of it and pull it back down to try to get the cutting voltage back in range.  Usually though, the DTHC doesn't kick in fast enough, and this bug will have lifted the torch high enough to lose the arc, losing position in the cut.  Quite irritating.

Is this a known problem?  Anything I can do to alleviate it?

Thanks!

Are you using the Pn200 hand pendant with this machine ??

(;-) TP

No, keyboard + xbox 360 wireless controller.

You didn't say what release you are using. If you are using v0.66 I have had the same problem and it's one of the bugs, along with many problems in v0.66. IMHO v0.66 should be not have been released. Now with Mach4 sort of released with it's own set of problems, Art has abandoned correcting issues with Mach 3 even though the product is still being sold and will be for another year according to the website. Sometimes I wonder who at ArtSoft is doing their marketing plan... or if they even have one.  

Try v0.62. I use the "Stop" command and "Run From Here" instead of Feed Hold.

Yes, I'm on .66.  Well, that's ridiculous.  This is a big problem to go unaddressed.  An axis randomly creeping around for no reason?  It's pretty essential to functional CNC that the axis stay where you put them and go where you tell them.  Is there a more official place to ask support questions like this?  It's unacceptable that this is just one of those issues that you have to live with.

You can contact ArtSoft but I doubt they will respond. Every version of Mach 3 has some sort of quirks... it's like a box of chocolates, you never know what you will get (or not get). I guess you have to decide which quirks you can live with. Wait until you try to figure out how CV works. 

In this case the latest version is not necessarily the best option.