| 摘要 |
Apparatus is provided for controlling a parameter of an arc welding machine, such as the height and/or the lateral position of the welding tool. The apparatus includes a parallel circuit having first and second branches connected to a source of voltage, wherein the first branch includes the arc welding machine to be controlled, and wherein the second branch includes an electrical analog of the current-voltage characteristics of the welding machine when operating as desired. A differential amplifier is provided for comparing the current in the first and second branches and providing a parameter-indicative signal representing the current difference between the first and second branches. In addition, a control circuit is responsive to the parameter-indicative signal and is provided for adjusting various parameters of the welding machine, including the height of the welding tool and/or the lateral position of the welding tool.
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