THCAD-10 + hypertherm 45 (nonXP)

bjames28

Well if you can find that error (it is still working on my system) then just get rid of the call to endcut. It does nothing. As you can see I am not a SW professional!

o<endcut> sub
o<endcut> endsub

The reason for the endcut subroutine (when it actually does something) is to synchronize the Z position at the end of a THC controlled cut that uses an external THC. This is also needed if you just use hal components for THC in the current release or the 2.8-pre master. When using the external offsets branch the motion component is made aware of the Z height corrections and is close to being synchronized ( usually the height hold that is asserted as the torch slows down at the end of the cut makes everything synchronized by the time Z axis control is passed back to the motion component) at the end of the cut.

You can actually get rid of all the variable setting stuff as well if you are going to just set the cutting parameters from from your GUI or from SheetCam. My PP is so complex because I have been trying to do both with the source of the cutting parameters set at run time by a radio button on the GUI. I use the same material 98% of the time so I am strongly leaning towards abandoning the complexity of setting cutting parameters from SheetCam or what ever CAM you are using. I am thinking that I will leave the job shop type features to Grotius or Rod to explore as they are the ones that need (want?) these features.

John

I’m confused, is this all saying you can’t use the hyperthem45 (not XP) with the THCAD-10???

yes you can

I forget what this was discussing

This is a very old thread.

If you have a voltage divider you can use the thcad 10.
but I think the 45 is fixed at a 50:1 divider. the 45xp has links where you can change the divide ratio (20:1 to 30:1 is better)

At 50:1, you are only going to read about 6 volts max when torch voltage is 300v so the resolution is not as good.

With a 50:1, the THCAD-5 is a better option as it has a 5 volt scale so its full scale torch voltage is 250 v
It did not exist when this thread was written.

Cutting voltage won't exceed about 150 volts. On piercing, it may briefly go over 250 volts but we don't care about voltage then and the thcad-5/10 are rated to handle 500 volts overvoltage on the board itself so its perfectly safe.
I'f you have already got the thcad-10, just use it. I'm sure it will have enough resolution to do the job.

Okay, yeah I already have the THCAD-10. And the hypertherm 45 (not xp). I’m sure it’s enough clarity. So I’ll just wire it up the way the xp is wired up, right?

It seems I had been a bit of a Muppet.... Too many projects + work distraction...

I was considering changing the 2k resistor within the pmx45 to change the divided output from 1:50 to 1:20 or something else (1:10 with an offset of -6v)

The problem I was having was offset....

Given the range of the thcad-10 is 10 volts, and anything less than ~70 torch volts and anything greater than ~170 torch volts given these are outside of the cutting range ( by a fair amount ), hence any voltage above and below this should be ignored and the torch (z-axis) should not rise, fall or try to track the voltage ..... When in doubt... Stay put....

Instead of thinking of the problem as a voltage divider change, I realised that this will only change the signal gain (plus I am reluctant to put a soldering iron to a perfectly good low mileage plasma cutter)

I thought about using an opamp, to simply offset the voltage, and then amplify the signal and have come across a few cheap ad620 development boards which offer the opportunity to do just that very simply and require:

- Two ad620 boards (first provide signal offset at a gain of 1, then amplify the signal with a signal gain 2.5)

- An isolated power supply providing dual (+/0/-) 12 volts for the opamp. A dual supply is required to provide the offset stage.

... Hence that is the plan at present ... Just awaiting the slow boat from China with boards to try out.. (more time to get my head around linuxcnc under the hood)
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LINK REMOVED

haha.... seems I've been cloned ..... I thought when I just read it, it sounded familiar.

robertspark wrote:

haha.... seems I've been cloned ..... I thought when I just read it, it sounded familiar.

Man, Tommy has a good memory!