There is provided a process control system including a plurality of functional modules for sequencing a plurality of operations of a machine, such as a plastic molding machine, wherein the functional modules include a static electrical control circuit. The static control circuit is comprised of an input circuit for receiving alternating-current signals; static direct-current logic means for performing an electrical function and then providing a direct-current output signal; static direct current to alternating current converter means, such as a triac switching circuit, coupled to the logic means for providing an alternatingcurrent output signal from the direct-current signal; and, actuatable means such as a solenoid controlled valve, coupled to the converter means, for upon energization, providing at least one of the plurality of machine operations.