Torch Height Controls - Command THC

Command THC The Command THC is a microprocessor-based torch height control system which accurately sets the initial piercing height and controls the torch-to-work distance of a plasma torch during cutting operations.

Torch-to-work distance is crucial to maintain optimal cut quality. The CommandTHC works with X-Y cutting systems to control this critical parameter and maximize plasma cutting quality and productivity.

X-Y torch lifter  
Limit switches
Upper and lower inductive proximity sensors
Max. Z-axis speed
Max. Z-axis stroke
200 ipm (5.0 m/min)
8 inches (200 mm)
Total weight with
torch mounting block
18.25 pounds (8.4 kg)
Positioning resolution 0.001 inch (0.025 mm)

THC control function
Set point resolution
Set point range
0.5 volt
50-300 volts
Maximum control
±1 0.5 volts
Voltage feedback
1/40.95 of arc voltage

Initial piercing height
control function
On/off signal provided by CNC
Initial piercing height
Set cutting height; pierce height is automatically computed
Set point resolution
Set point range
Pierce height factor
Work contact sensing
Work clear
Pierce delay range
Pierce delay resolution
Machine acceleration delay
Machine acceleration delay
0.010 inch (0.10 mm)
0.020—1.00 inch (0.5—25.4 mm)
1 to 3 times the cutting height
Ohmic contact and/or motor  torque
Loss of Ohmic contact
0 to 5 sec
0.010 sec
0.00 to 1.00 sec
Resolution 0.010 sec

Initial piercing height stall force 1—10 Relative setting

Initial piercing height speed 1—10 Relative setting

Homing speed 1—10 Relative setting

Miscellaneous features Ability to be synchronized with parallel THC systems
Electrically floating interface
Machine safety interlock
System fully complies with the following standards
and directives:
CSA 22.2 #60
UL 551
EN 60974-1
EN 50199
EN 55011
Low voltage directive
EMC directive
* Information subject to change without notice.
** User supplied display and keyboard are required
Superior height control
  • The system will respond to arc voltage changes of less than 1 volt.
  • Maximum speed of retract exceeds 200 ipm(5.0 m/min).
  • Built-in Ohmic touch-retract initial height sensing(IHS) feature ensures accurate, repeatable initial piercing height settings.
  • A work-clear feature senses the loss of Ohmic contact for accurate positioning, even on thin, flexible sheet metal.
  • Built-in motor-stall IHS feature is always active and serves as a back-up for the Ohmic IHS, when cutting non-conductive material surfaces, such as painted plate or underwater cutting.
  • Rapid pull-back feature moves the torch away from the workpiece if a touch is detected during cutting.* This collision avoidance feature will prevent crashes such as workpieces that tip up or buckle.
  • CNC-controlled arc voltage control can be disabled during cornering to keep the torch from diving at corners.
  • Over-voltage protection automatically eliminates "torch diving" during large, out-oflimits arc voltage fluctuations; such as kerf crossings or cutting off the edge of a plate.*
  • Built-in, advance preflow reduces cycle time by allowing gas to preflow during the IHS cycle.
  • Optional breakaway is designed to reduce or eliminate damage to the torch due to accidental collisions in all axis.

Maximum reliability
  • Heavy duty, 100% duty cycle. Built-in power-up diagnostics. Backed by Hypertherm warranty: two years on all control modules, one year on torch lifter station.

Flexible operation
  • An optional operator control pendant with backlit liquid crystal display allows easy system setup, operation and monitoring. Distances can employ inch or metric units. Programmable set points for cutting height via operator control pendant. Programmable delays for pierce time, machine motion acceleration time and torch retract delay time. All features and parameters can be set remotely via RS422 serial interface, for complete CNC control.
  • System designed to work with any AC line input voltages currently available worldwide. System diagnostics can be displayed or transferred to the CNC.

Optimized X-Y torch lifter station
  • Advanced-technology, high-torque motor allows 50-pound(25 kg) load capacity. 8 inches(203 mm) active stroke.
  • 200 ipm(5 m/min) maximum z-axis travel speed.
  • Positioning resolution 0.001 inch(0.025 mm).
  • Moving mechanical parts are protected from the environment by a Teflon-coated, fiberglass sealing band and a mechanized shield.
  • Moving parts are dry lubricated; no oil lubrication is required. Non-contact/inductive, upper and lower-limit switches.