D31 is a cabinet-mounted inverter, the power range is 0.75KW~500KW, the incoming voltage is 380V~480V, and the control methods are sensorless vector control and vector control. The speed sensorless vector control is a kind of vector control, but without a speed sensor, the speed feedback value of the motor is estimated through the calculation of the motor model. The control accuracy and dynamic performance of the speed sensorless vector control are not as good as the vector control with speed closed loop, but it also has the advantages of simple system, no need to maintain speed sensors, and low price, especially for fans and pumps. The traditional V/f control also does not need a speed sensor, but for high-power fan and pump motors, such as V/f control without current loop control, it is easy to cause current fluctuations. The speed sensorless vector control not only has a speed closed loop but also a current closed loop, and the steady-state current of the motor is more stable. D31 has a wealth of client terminals, including 8 digital inputs (LI1~LI8), 2 analog inputs (AI), 2 relay outputs (TA), 2 analog outputs (AO), 5V auxiliary power supply for analog power supply Fixed input, 24V auxiliary power supply is used for digital input, all LI/TA, AI/AO can be freely programmed to define functions.

MODBUS interface is standard configuration of D31, no option is required. The D31 can be connected to higher-level automation systems via MODBUS.

D31 series inverter has built-in PID function, which is more flexible in operation. There are many ways to control the interface, which can be hard-wired or communication.