how to get Mesa THC values

Hello I have a Mesa 5i25 + 7i76 last weekend I have hooked up the Mesa thcad I am reviewing some examples from John but I am in doubt how to calc this values for my machine. where do they get? I have an Hyperthem 65 and the THCad 10V

setp thc.scale-offset 119000
setp thc.vel-scale 0.00037866834

# this might need to be increased
setp thc.correction-vel 0.0001

someone can help me?

echesortux wrote:

Hello I have a Mesa 5i25 + 7i76 last weekend I have hooked up the Mesa thcad I am reviewing some examples from John but I am in doubt how to calc this values for my machine. where do they get? I have an Hyperthem 65 and the THCad 10V

setp thc.scale-offset 119000
setp thc.vel-scale 0.00037866834

# this might need to be increased
setp thc.correction-vel 0.0001

someone can help me?

some time ago I start a tutorial how to calibrate a THCAD10 board, it isn't finished (shame on me) but I believe that is enough to understand the principles.

jtctech.pt/wiki/index.php?title=Mesa_Thcad10_calibration

download the excel file, place the values and it's almost everything done I use the frequency divided by 32 in the tchad10.


João

There is a section on calibration for the THC in the manual...
www.mesanet.com/pdf/analog/thcadman.pdf
I then used a known voltage source such as a battery and meter to confirm the voltage in linuxcnc was correct.

# this might need to be increased
setp thc.correction-vel 0.0001

You can adjust this for your machine, as I recall if set too high the Z axis will oscillate up and down during the cut by overcompensating.

Rick G

Currently I have connected in this way (picure attached). someone can tell me if the hooked up is correct?

Hi John, how do you get this values? I am trying to understand your plasma.hal to using with my machine.

setp thc.scale-offset 119000
setp thc.vel-scale 0.00037866834

# this might need to be increased
setp thc.correction-vel 0.0001

thanks

setp thc.scale-offset 119000 = frequency 0V ?

setp thc.vel-scale 0.00037866834 = 300v/(916100Hz - 119100Hz) = 0.000376411 aprox.

setp thc.correction-vel 0.0001 =???

echesortux wrote:

setp thc.scale-offset 119000 = frequency 0V ?

setp thc.vel-scale 0.00037866834 = 300v/(916100Hz - 119100Hz) = 0.000376411 aprox.

setp thc.correction-vel 0.0001 =???

1- yes, is the measured freq at 0v
2- slope of the line, I prefer to make some measurements and calc a trend line on excel to get the slope value.
3- I use a modified THC comp, so I cant help you on this one.