How to control the inverter through PLC

1. Touch screen controls the inverter through PLC

1. At present, the control of frequency converters in general needs to use PLC to communicate with the frequency converter, read the information of the frequency converter, and then the touch screen communicates with the PLC to complete the control of the frequency converter start, stop, and monitor the operating frequency, current, voltage and other functions of the frequency converter. 2. The method of the touch screen controlling the frequency converter through the PLC is to connect the touch screen to the programming port of the PLC, and then expand a 485 interface on the PLC, and then the PLC and the frequency converter communicate through 485. These two communications can communicate without affecting each other, and then write the corresponding program as needed to make the touch screen change the frequency of the frequency converter through the PLC.

2. No PLC required, touch screen directly controls the inverter

In order to make the inverter run, two conditions must be met, namely the start signal and the frequency signal. Therefore, the essence of the touch screen controlling the inverter is to realize the start signal and frequency signal of the inverter on the touch screen. The touch screen and the inverter are connected through communication, so this problem boils down to the touch screen as the communication master station and the inverter as the slave station to establish the connection. The inverter has an RS485 interface and supports the MODBUS protocol. Therefore, we only need to establish a MODBUS slave station in the touch screen. Let's use a practical case to show you the method and steps of directly controlling the inverter with a touch screen.

3. Communication port between touch screen and inverter

1. RS485 communication port of Delta inverter

2. Communication port of Weilun touch screen

3. Here we need to connect the touch screen and the RS485 terminal of the inverter in parallel.

4. Communication settings between touch screen and control inverter

1. Set the inverter's operation instructions and frequency instructions to use MODBUS communication, set the communication address to 1, the communication baud rate to 9600, and the data check setting (E, 8, 1) even check for RTU. 2. Set the touch screen's communication parameters to: MODBUS RTU format, 9600, E, 8, 1

5. Operation steps of touch screen directly controlling inverter
1. Make communication line and connect touch screen and inverter 2. Set communication parameters of inverter 3. Set communication parameters of touch screen 4. Make operation screen of touch screen 5. Wiring and debugging of master station controlling slave station