Abstract: A multi-operator grid system for stud welding is disclosed which works in conjunction with a microprocessor controlled single stud welding power supply. The multi-operator grid system utilizes a single multiplexer interconnected with a plurality of weld stations each of which includes an isolator, hand held terminal and stud welding gun. Each hand held terminal working through the multiplexer can program the microprocessor stud welding supply for parameters of pilot arc and welding current energy and cycles. The microprocessor controlled stud welding supply, through the multiplexer, provides read outs to printers and to the hand held terminals of the resultant stud welding parameters such as total welding energy, weld current and the like. The multiplexer, working in conjuction with the microprocessor controlled stud welding supply and the isolators, controls the pilot arc and weld current to the stud welding guns as well as the plunge thereof.

Abstract: Stick and stud welding apparatus which utilizes a microprocessor and related RAMs, ROMs and peripheral interface devices to control the welding parameters. The ideal desired weld current and weld cycles in the case of stud welding can be selected depending upon the mode of operation and/or stud conditions. The program for the microprocessor instructs the microprocessor to periodically compare the actual welding current to the ideal current, compute the difference and alter the phase firing time of an SCR bridge to compensate or adjust the welding current to the ideal current. In the case of stud welding mode, the program further instructs the microprocessor to reference the selected number of cycles, compute the total energy delivered across the stud and workpiece gap from actual current, welding terminal voltage and time and enlarge the number of actual weld cycles to a given percentage of that initially selected to provide a total energy input to the stud as selected.