All switch input and output ports are isolated by the photoelectric coupler, and the trigger pulse output circuit of the thyristor is isolated by using the photoelectric coupler, and the transformer isolation is used to prevent the high voltage of the main circuit. In order to ensure the normal operation of the microcomputer, the ground wire of the input port is also isolated from the ground wire. Although the isolation amplifier can be used to isolate the internal and external ground wire, but because of the use of the amplifier module with the transformer coupling technology, the ability to resist interference is limited. To this end, the analog quantity is converted into a digital quantity before entering the computer, and the photoelectric coupler is used to isolate each digit.

Because the photoelectric coupler is a kind of current type device, it has a good inhibition effect on the narrow pulse interference signal, and can get better anti disturbance ability and high conversion accuracy. Power supply anti-interference: microcomputer power supply using the magnetic AC voltage regulator, super isolation transformer, dual line low pass filter, anti interference type microcomputer with switching power supply mode. Experiments show that this system has good anti-jamming performance, which can ensure that the computer is not affected by AC power supply, and the peripheral circuit is from AC voltage stabilizer. Other anti interference measures and input signal of the filter network, digital filtering procedures, trap procedures, the use of integrated circuit, power line and control line separate wiring, computer signal lines using shielded wire.