Circuit process controller is an intelligent instrument witch divergence in distributed control system can reach one loop, with the property of high reliability, rich function and well flexibility.

This still enabled each half cycle to complete its loop through the one-half of primary in the plate circuit and one-half in the cathode circuit.

In order to restrict the rising rate of fault current caused by short circuit on one arm of bridge of inverter, a kind of device named current loop protection circuit can be adopted.