1. A method of welding a cylindrical workpiece by use of a robotic welding system, the method comprising: loading a substantially cylindrical workpiece into a workpiece support; positioning a robot arm, carrying a welder, to a start position; inputting by an operator a value representing a size of the cylindrical workpiece, to a robot controller via a robotic interface; obtaining a control program, corresponding to the value input to the robotic interface; initiating operation of the control program; moving the robot arm a preprogrammed distance towards a work surface of the workpiece, based on instructions from the control program; undertaking a welding procedure in accordance with instructions from the control program including, initiating operation of the welder; moving the welder in a pattern appropriate for the welding process being undertaken in accordance with the control program; and moving at least one of the workpiece and welder relative to each other so as to perform the welding operation as determined by the control program.