The Application of modbus TCP in hmi

Ⅰ. Reasons for WECON hmi choosing modbus TCP/IP

1. The application layer of WECON HMI makes use of Modbus TCP, which makes industrial Ethernet data exchange achievable.

2. It’s easier to interconnect with different systems: available to management network, real-time monitoring network and field devices communication.

3. Low cost of network’s implementation: available to apply a common network component.

4. High data rate: high transmission capacity, the transmission result of 100M Ethernet is 4000 Modbus TCP messages per second, while each message can transfer 125 words, which is equivalent to 4000×125=500000 analog data (8000000 switch).

  

Ⅱ. Parameter Settings

   The case here PC is set as Slave(lower computer), and touch panel as Master(upper computer).In this way, PC can communicate with HMI.

   The IP address of PC is set: 192.168.1.2. The two screens of project is edited by the use of WECON configuration software, the device type of one is chosen ModBus TCP Slave, the other is ModBus TCP Master.

   The project of Slave is downloaded to HMI and Master’s is simulated online.The network of HMI and PC are connected by communication cable.

 * Setting of HMI project

   The setting of communication port configuration: 

   The communication port is selected Ethernet and device type is ModBus TCP Slave. The Ethernet parameter is set: 192.168.1.2:502(this IP address should be the same to PC’s). The network type is set: TCP_Client_2N. The setting is as shown in figure 1.

 

 

Figure 1

    

HMI IP SETTING

 192.168.1.5(This IP is used for debugging to check whether it’s connected to PC or not).The setting is as shown in Figure 2

 

 

Figure 2

  The design of screen is as shown in Figure 3:

 

Figure 3

 * Setting of PC project

   The setting of communication port configuration: the communication port is selected Ethernet and device type is ModBus TCP Master.The Ethernet parameter is set: 192.168.1.201:502(As long as this IP address is different from HMI’s in the same network segment). The network type is set: TCP_Client_2N. The setting is as shown in figure 4.

 

Figure 4

  The design of screen is as shown in figure 5:

Ⅲ. Conclusion

   Modbus protocol is field-bus protocol which only consists of physical layer and data layer. It’s particularly suitable for the application situation with simple architecture and low cost. Through supporting Modbus TCP/IP protocol, WECON touch panel is able to communicate with PC and other devices.It not only reduces the cost of system design, but also increases the versatility of the equipment, which provides convenience for users.

Note: The hmi in this application example is LEVI-777A