The schematic diagram is shown in the figure. The board includes two parts for temperature control, and the temperature control input signal uses a standard current signal of 0 to 20 mA . The current signal is taken out by the R5 2 voltage signal, and then the voltage is calculated with the W terminal voltage. The integrated block U 1D amplifies the output, and the output voltage maximum has a W terminal potential level to determine the temperature control circuit, the temperature control input. The 0 to 20 mA current signal is compared with the voltage of the external potentiometer through the R 52 voltage signal . The differential pressure between the two is amplified by U 1 D to change the output voltage. The range of variation is R 54 . , R 51 decided, generally set at the factory has been set at about 10 times, the pressure difference between U R 52 and U W2 is 0.1V , U 1 DThe voltage at the output should be around 1V . In normal operation, the output BH point is low, and after the temperature control is input, the output is high, and the output power of the intermediate frequency power supply is low. To achieve the purpose of temperature control. The temperature is determined by the high or low potential of the W terminal. Under normal circumstances, the high and low W values of the temperature indication can be adjusted accordingly.