thc 300 problem

[cristian gabor]

hi

I sorted out the some problem i had with thc 300
it was that i was confused about post file in sheetcam(where i supposed to enter my switch travel)with the tap file resulted from sheetcam because in sheetcam i fave the "run postprocessor" button labelled with a green "P" letter.so i was thinking that the file where i have to insert the switch travel is the file resulted from clicking that button

i have now another problem :when i run the code in mach with the THC on the torch will dive in to the plate.
it does not happen if i turn of the THC
i have the following :
if the torch is siting on the plate and z = o jog the z axis up the dro increases (goes positive )
hit "z home " and the z axis goes down torch toches the plate z continues moving until trips the limit switch stops then lifts up a Little bit and zeros the z dro
i have set the THC delay in mach to 1.5
the THC300 front panel leds for up and down matches the screens up and down leds
i have changed in ports and pins the torch up , torch down from active low (box checked "v") to active hi (box unchecked "x" )
and the torch was getting lifted up allot so i did set them back to active low
the THC max is 30 the THC min is -30

if i start a job with coarse and fine coarse centred the fault led does not go of so i had to turn the coarse CCW to about 11 a clock
(if it was to be a analogue clock indicator )to get the fault led to go of
i have grounded the plasma (pwmax 1650) to a rod driven about 1.5 meter in the ground
my plasma table is 6.5/2.1 meters big so i fitted all electronics on the gantry to keep all the cables short not to risk any interferences but my material table is not electrically connected to my cnc table
so it should not be a problem
now what can by the problem that the torch dives in to the material during a 350 mm straight line ?

PS Tom i could not find the mp1000c manual on candcnc web page

Cristian

[cristian gabor]

pics

[C.Michael]

during the 350mm run,does the torch pick it self back up to the proper running height or does it just keep dragging all the way..in picture 2 I can see the screen but cant read any numbers..in the area of the "Feedrate" of the screen,what do you have at the -THC rate- number..I turn down this to 10 and what that does is slow down the reaction time of the thc,it does not react as fast..at the begining of the pierce,the voltage is high and then it settles down to the proper voltage at the given heighth..if the thc reacts fast to the high voltage,it will dive,trying to reduce the voltage..if the THC rate is slowed down,then this gives the voltage time to settle to the normal voltage.

[cristian gabor]

HI
i made the bench test and i solved the problem
i was locking this morning for a variable power suply and i found a variable soldering iron
opened up unscrew the leads that were going to the soldering iron (inside the box) , placed a bridge rectifier and a capacitor (make sure if you do the same the capacitor it is rated for more than vovltage is coming out from the variator otherwise you will see smoke )and there was my variable power suply 0 volts to 220 volts (i got electrocuted so take care)
next i teked the sensoar board and thc300 box lied them on bench work , conected the db 9 cable betwin sensor and thc300 box , aplied that voltage to my sensoar board , and powered the unit.
then i set the voltage from the variable power suply (variable soldering iron) to 135 v , the same as the voltage coming from my plasma to the sensor and it behaved the same as on the cnc plasma table
the thing that i did next is what solved the problem
on the thc300 card are 2 knobs one near to the cable that is going to the lcd display (vr 2) and the other one nearer but not very close to the 25 header going to paralell port (vr 1 )
this knob is where the problem was
the condition that i had it was that i could get only down led or fault led on
so i did set the front panell knob to the point where the fault led just camed on and the turned vr1 cw about 20 turns until the fault led camed of and down led camed on
the continued to turn it until the up led camed on (i stoped counting at 100 turns )
there is a big diference betwin having fine coarse switch on and of
for the begining try with the switch of

Cristian
Regards