This is where the operator sets two critical cutting parameters: initial height and arc voltage. The remote control is the HMI, or human machine interface. It "divides" the voltage signal and sends a smaller signal voltage to the control console. The voltage divider card monitors power supply voltage during cutting. This device usually consists of a voltage divider card that is mounted inside the plasma power supply. It receives input commands from the remote control, sends output commands to the torch positioner, and monitors position feedback and voltage signals. Screw drive, rack and pinion, and belt driven mechanisms are used to translate motion. This device moves the torch up and down in response to signals from the control console. This "torch to work" distance or "standoff" is critical to both cut quality and parts life. But all use the same basic elements to control position of the torch relative to the material being cut. Each of these automatic THCs has a variety of functions and features.
There are a variety of torch height controls, or "standoff controls," on the market. In either case the shop is not getting the most out of its cutting operation.
The THC is either not working properly or the operator has not been trained on how to use the equipment. In many fabrication shops you will see the torch operator manually driving the torch up and down while cutting-his eye on the torch and his thumb on a toggle switch.
But it is also the piece of equipment on the cutting machine most likely to be misused, nonfunctional, or even missing. The automatic torch height control (THC) is one of the most important elements of the mechanized shape cutter.