A: The circulating variable frequency pump is one of the working modes of the GD300-16 HVAC special mode. In the long-term stable operation of the water supply system, the variable frequency pump has been running for a long time, which will affect its service life, and other variable frequency pumps are not involved in operation. In order to prolong the service life of the variable frequency motor, under the stable state of the system, all the variable frequency motors to be started run in turn according to the set cycle.
First, the inverter coast stop, and then controls the lower limit frequency of the cyclic variable frequency motor to be started as the initial set frequency, and superimposes PID1 to adjust the output frequency on the basis of this frequency as the final set frequency to start running, and finish the cycle process.