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SHIELD port（the screen printing word named SHIELD in PCB）connect with torch retaining
cap collision detection wiring.
The plasma power source anode is connected with GND, cathode is connected with torch
nozzle, and the voltage of nozzle is negative voltage. During torch work, the absolute value of
the arc voltage is greater than 100V. Because voltage is higher and interference is bigger, it is
necessary to control by quarantining voltage divide. THC voltage divide board use voltage
divide circuit which ratio is 100: 1, the arc voltage range which we can measure is 0V~660V.
Warning: the plasma power arc voltage sampling cable need use HVSC, plus-n-minus
should not be connected contrary. If arc voltage plus-n-minus is connected contrary, auto height
control will not work. Plasma power source arc voltage wiring need connect with wiring pile in
plasma power source output, it do not connect with torch and work piece, it can avoid disturbing
by the high frequency.
3.3.2 torch retaining cap detection circuit port
THC can has two way of IHS :
Torch retaining cap IHS;
Proximity switch IHS.
For torch retaining cap IHS, the torch retaining cap need connected to SHIELD port by high
voltage cable. The connection as follows:
Unique Solution
figure 3.12 voltage divide board wiring diagram
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