Sheetcam post for Uccnc and Mini THC

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Sheetcam post for Uccnc and Mini THC

Postby rforrest » Mon Feb 25, 2019 11:42 pm

I just completed a 5x5 plasma table with a UC300-5lpt. I originally used a proma thc but quickly discovered it's limitations. I've got a miniTHC on the way, I was wondering if anyone has a post available for sheetcam, compatible with uccnc that will handle the c-axis protocol? Or have a example i can look over to see what i'm doing wrong? I been trying to modify one but i keep getting errors. Thanks for any help.
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Re: Sheetcam post for Uccnc and Mini THC

Postby Robertspark » Tue Feb 26, 2019 12:13 am

Here is what I use to use:

https://drive.google.com/file/d/1Wk_AZW ... sp=sharing
miniTHC postprocessor for sheetcam

https://drive.google.com/file/d/11Jazqu ... sp=sharing
miniTHCtoolset for the hypertherm 45 (non XP) metric
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Re: Sheetcam post for Uccnc and Mini THC

Postby Robertspark » Tue Feb 26, 2019 12:16 am

The c-axis protocol is shown within this function of the post processor:

Code: Select all
function MiniTHCSetting()
   if(MiniTHCVolts > 0 and MiniTHCDelay > 0 ) then
         post.Text ( " G92 C0  \n" )         
         post.Text ( " G0 C8   \n" )
         post.Text ( " G4 P100 \n" )
         post.Text ( " G92 C0  \n" )
         post.Text ( " G0 C",MiniTHCVolts," (MiniTHC Voltage Setpoint) \n" )
         post.Text ( " G4 P100 \n" )
         post.Text ( " G92 C0  \n" )   
         post.Text ( " G0 C",MiniTHCDelay," (MiniTHC Delay, hundreths of a sec) \n" )
         post.Text ( " G4 P100 \n" )
         post.Text ( " G92 C0  \n")
         post.Text ( " G0 C5   \n" )
         post.Text ( " G92 C0  \n" )
   elseif(MiniTHCVolts > 0 and MiniTHCDelay == 0 ) then
         post.Text ( " G92 C0  \n" )         
         post.Text ( " G0 C9   \n" )
         post.Text ( " G4 P100 \n" )
         post.Text ( " G92 C0  \n" )
         post.Text ( " G0 C",MiniTHCVolts," (MiniTHC Voltage Setpoint) \n" )
         post.Text ( " G4 P100 \n" )
         post.Text ( " G92 C0  \n" )   
         post.Text ( " G0 C5   \n" )
         post.Text ( " G92 C0  \n" )
   else
         post.Text ("(No THC Voltage / Delay Set, using previous settings) \n")
   end
end
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Re: Sheetcam post for Uccnc and Mini THC

Postby Robertspark » Tue Feb 26, 2019 12:20 am

You also need to add these values to within your tooltable (Custom Tool Parameter) so that sheetcam can pass the values to the miniTHC via gcode.

Code: Select all
post.DefineCustomToolParam("PlasmaTool", "MiniTHC volts", "MiniTHCVolts", sc.unit0DECPLACE, 130, 0, 200)
post.DefineCustomToolParam("PlasmaTool", "MiniTHC delay -hundreths sec", "MiniTHCDelay", sc.unit0DECPLACE, 1, 1, 20)
Robertspark
 
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Re: Sheetcam post for Uccnc and Mini THC

Postby rforrest » Tue Feb 26, 2019 12:36 am

Perfect, thanks Robert. I see where I was messing up now. I kept getting a compare to nil error. Thanks again!
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Re: Sheetcam post for Uccnc and Mini THC

Postby Mr.Hotwire » Wed Feb 09, 2022 11:28 pm

Can you give a little info on the C-Axis Setup in UCCNC?

I have the C Axis Step Pin Set to Pin2 Port 3 (Thats the C-Axis/Charge Pump Pin (#6 on the 8P cable).

But Im confused about the rest.. the 6000-25000 steps/sec, and the frames 100-500 msec.
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Re: Sheetcam post for Uccnc and Mini THC

Postby Robertspark » Fri Feb 11, 2022 1:05 pm

you need to set up the C axis (the ACTUAL C-axis) in UCCNC with some step setting and the acceleration like a normal axis.

set the axeleration as high as possible (just choose a big number any number)

for the steps per, set it at 1

set the maximum axis feedrate / velocity as 10,000 steps per second or 600,000 steps per minute.

basically you are jut trying to output a pulse train which the minithc can understand.

if you put the following into a file / macro and run it as a file it should change the voltage setting on the minithc.

G92 C0
G0 C9
G4 P100
G92 C0
G0 C140 (MiniTHC Voltage Setpoint)
G4 P100
G92 C0
G0 C5
G92 C0

if you change the "C140" to C125 it will change the voltage to 125V setpoint (you can set this up in a macro or from a screen element if you want via a macroloop)

also it has an auto voltage sense / setpoint. if you turn the voltage knob all the way to the right or left (I forget which) it will show A on the screen at some point (either after the highest or lowest voltage number is shown on the display)

the A is for Sample and Hold.... basically you set it on A and run your touchoff sequence, retract to pierce height, torch fires, drops to cut height and the machine begins to move when it gets the ArcOk / transfer signal, after a couple of seconds (adjustable in the miniTHC settings) it will sample the voltage at that point and it will track that sampled voltage for the rest of the cut sending thcup / thcdn signals to the motion control software.

Note (again) I don't use UCCNC at this time so I don't write macros or macro loops or anything like that any more (I don't have the time).

good luck.
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