Abstract: An electric arc welding control unit for controlling welding parameters such as voltage and wire feed rate. Manual potentiometer controls are operated from the outside of the unit to select values for the welding parameters. An override switch inaccessible to the outside of the control unit defeats the exterior controls and actuates second control means comprising interior controls which can be preset to define desirable schedules of welding parameter values. A selector switch is used to select one of the welding schedules. When they are defeated the exterior controls become dummy controls which do not affect the welding schedules.