SPECIFICATIONS
11
CommandTHC for X-Y Table
Instruction Manual
2-3
General
Hypertherm’s X-Y CommandTHC is a torch height control/initial height sensing (THC/IHS) system designed for plasma
cutting applications on a X-Y cutting table (Figure 2-1). The system uses the plasma arc voltage to control the physical
stand-off (distance) between the torch and workpiece during plasma arc cutting. IHS is accomplished by ohmic contact
sensing or by a limited force stall detection method. The
system includes the following:
• THC control module (Figure 2-2) The THC control module houses 2 microcontrollers, a realtime controller
and an interface controller. This unit provides initial height sensing, arc voltage control and interfaces with
the torch lifter, the CNC machine, operator pendant and the plasma power supply through standard discrete
I/O interfaces and optional extended RS-422 serial interfaces.
• Plasma interface assembly with voltage divider (Figure 2-3) The plasma interface houses an interface
PCB which provides a communications link between the THC control module and the plasma power supply.
The voltage divider provides a 41 : 1 signal which is derived from the cutting arc voltage. For example, if the arc
voltage is 150 volts, the resultant 3.66-volt output signal is used to control the stand-off distance between the
torch and workpiece during plasma cutting.
Note:
HyPerformance (HPR) plasma systems do not have an interface assembly. HPR systems have an
interface board that mounts in the power supply.
• X-Y lifter assembly (Figure 2-4) The torch lifter station, under control of the THC control module, positions a
torch head vertically above the workpiece. Its maximum stroke is 8 inches (200 mm) between the home and
lower limit switches. It is driven by a stepper motor attached to a leadscrew. An encoder is provided for stall
IHS sensing, and to detect gross errors during normal operation. A lower limit switch detects maximum travel
in the downward direction. A home switch is provided to detect when the lifter is in the uppermost position.
A power-off brake is energized after power up, and allows controlled motion of the torch. It is powered off during
“Maintenance Mode” to prevent the torch from being accidentally moved. An optional torch breakaway kit is
also available.
• Operator pendant (optional) (Figure 2-5) The operator pendant is a remote control which includes an
LCD display and keypad used for THC setup and control (parameter entry and menu selection).
•
Torch breakaway kit (optional)
(Figure 2-6) The torch breakaway (collision sensor) provides a level of
protection for the torch, lifter and X-Y table. Air pressure locks the torch to the THC lifter assembly. The air
pressure can be adjusted to change the force required to trip the breakaway. Upon side impact, the breakaway
releases from the lock position and allows the torch to float. See Figure 2-4 for torch mounting dimensions with
and with out the breakaway.
