PID input and output are values ??from 0-32767. You can map this value to a certain output port and use the duty cycle type output. If the period is set to one second, then its output duty cycle will be high. The high power frequency is 0.99 seconds, the low power frequency is 0.01 seconds, and the cycle is reversed when the duty cycle is low. It can also correspond to the analog output port, such as 0-10 output. When the PID output is 32767, the analog port output is 10V. When the PID output is 0, the analog port output is also 0V. This is how the inverter is controlled. It is equivalent to a variable resistor, which is a commonly used volume. Knob.