(1) control the start and stop of welding equipment. (2) control the action of the electromagnetic valve in advance aspirated and the lag to stop the gas, the Welding Accessories is well protected. (3) control the water pressure switch action to ensure that the torch to be a good cooling. (4) Control the arc extinction: MIG welding arc are generally three types: the burst off the arc (wire contacts the workpiece, the power to make the wire in contact with the workpiece at the melting wire explosion ignited the rear arc); slow send wire arc (wire slow to send to the workpiece until the arc is ignited, then increase the wire feed speed), and the Withdrawing arc (wire contact with the workpiece, power Withdrawing the wire ignited arc). Extinction in two ways: the current decay (wire feed speed corresponding decay, fill the crater, to prevent the wire and workpiece adhesion) and wire back to burn (to stop the wire feed welding power, cut off after a certain period of time). (5) controls the wire feed and car (or table) mobile (automatic welding). Program control is automatic. Semi-automatic welding start switch mounted on the handlebars. When welding after the start switch is closed, the entire welding process in accordance with the procedures set automatically. Program control of the controller by the composition of the delay controller, arc controller, put out the arc controller. Process control systems will be Welding Wire China, wire feeding system, torch and walking systems, gas and cooling water system organically combined, form a complete, automatic control system of welding equipment. In addition to the programmable control system for high-end welding equipment parameters automatically adjust the system. Its role is to changes outside interference when the welding parameters can be automatically adjusted in order to maintain the welding parameters constant, to maintain normal and stable welding process.