Weld controls can be incorporated into automated weld cells and take their initiation signals from the numerical control center of the cell. The weld control will control the actual weld functions being performed within the time allotted by the NC center. Weld controls are capable of sending whatever data is needed back to the NC center to record that the functions are complete or data generated during the operation.
Reference: RWMA - Resistance Welding Manual 4th Edition