1 pump control program, complete the control of 1 pump, as shown in figure 4-18. The procedure first calls the PID reverse path procedure and interrupt subroutine. Then set the frequency of pump 1 to m1.3; Set the variable frequency running mark M1.0 of pump 1. When the pressure inside the tube is less than the set value, the speed of the inverter reaches 100%, and the timer T40 starts 0.5s. When the timer expires, switch the output pump 1 to the power-frequency operation, and set the power-frequency operation mark of pump 1 to m0.5