New THC Feature....options [long]

[jimcolt]

Tom,

Industrial robot manufacturers and integrators often use their software for torch height control in mig welding applications....they often call it "seam tracking" and it uses arc voltage to maintain the proper wire stickout. It is quite complicated as the robot has to compensate as many as six axis (at least it seems complicated to me!)

Over the years we have worked on hundreds of plasma cutting/six axis robot applications with this seam tracking voltage input modified for plasma voltage height control...it works pretty well in most cases.

Jim

[WSS]

Jim,
those robots are something else! all the detail is amazing. you figure it has to know uphill, downhill and everything in between. And then add seam tracking, I think that has to do with the bevel on both parts to be welded. As the wire passes over the valley it will sense the change in amps and correct at the right point and reverse the oscillation.

A neighbor I had many years ago was a pipe fitter and a really good welder. One time I asked how he learned to do the over head and upside-down stuff and he said it was easy, just make the top look like the bottom. That is the kind of brain freezing formulas I try to avoid.

Once I get our Dynatorch up and running I will revisit the THC on a mig gun possibility. Our machines are three axis (X-Y-Z) so it should be pretty easy to configure and add to one axis. I read through some of the tech stuff on our Miller dimensions and they do have a external lead that is for a meter that use volts to convert to amps, I think it is 10vac for every 100amps.

Thanks for your guys' time!
Tommy
WSS

[Torchhead]

After messing around with the "features" part of this, I moved forward with the project: Reading a DC current in a conductor with a method that does not require breaking (cutting) any conductors or even opening the plasma cutter.

I have done several designs using Hall Effect current sensors but all of them had to be inserted in the conduction path. We started experimenting with using a clamp around probe (like the one I have on my Tektronix Current Probe) and found that a molded ferrite core clamped around the a heavy conductor with the proper magnetic characteristics and a linear hall effect sensor makes a very accurate low cost snap on non-contact current probe. I have one working on the bench with nice clean DC loads. I have the circuitry in the design to handle PWM and lots of noise type current waveforms but we have to get this hooked up in the real world of plasma. I have been putting that off since temperatures are hovering in the 100+ range in Texas and the shop is an unpleasant place to do hours of testing with scopes and current meters!

Our goal is to have a cost effective option for plasma cutting that adds useful features. We can't have an Option that costs more than the base price of the DTHC itself.

I have one of a new series of MACH screens that has the controls in place to do the Torch Current (in AMPS) feedback and some of the logic is in place to notify and trigger a "fault" if the cut current is outside a preset (set in the Cut Profiles window) value.

I would venture that we are still a few weeks from having a shipping product but all new DTHC components (DTHC Module, THC Sensor Card, etc) will be DCP (digital Current Probe) ready by July 24th. Currently, anything ordered after the 11th (today). will ship with the updated modules. We also will offer free trade-in's for anything bought since May of 09 with the purchase of the DCP option.

I have attached a screen shot of the new MP3000-DTHC with DCP screen shot. I will have pictures of the DCP (actual probe module) itself early next week.

Gotta go do some final packaging design