Abstract: An apparatus for simultaneously welding multiple molded plastic parts includes a power delivery module, a measuring arrangement, a parameter storage module, a user interface, and a controller, is designed for use with plastic parts that each have at least one fitting with a heating element and an identifying resistor. The power delivery module is designed to supply power to the multiple heating elements and includes a common power supply, multiple independently controllable power switching devices and multiple outputs, each designed for interconnection with one of the fittings. The measuring arrangement includes multiple interconnections for connecting to the heating element and identifying resistor of each fitting to which an output is connected. The measuring arrangement measures the resistance of the heating element and the identifying resistor of each fitting connected to the apparatus.