Generally speaking, in order to achieve Ethernet wireless connection between multiple PLCs, you must first make sure that the Ethernet cables must be connected correctly and establish a physical connection. Then the IP address needs to be set on the PLC side so that different PLCs can communicate with the same protocol. The last step is to establish a PLC-side data collection and exchange system, which requires setting up a folder for multi-file transmission on the PLC side and establishing a set of file reading, writing, searching and processing procedures. When a PLC issues an instruction, it sends an instruction to another PLC. After sending data, another PLC will respond according to the actual situation, thereby realizing data exchange between multiple PLCs.
The following takes Siemens S7-1200 as an example to introduce the wireless Profinet communication implementation process of two S7-1200 PLCs. In this solution, the Siemens PLC wireless communication terminal DTD418M, which is compatible with the Profinet protocol, is used as the hardware device to implement wireless communication.
During this process, users do not need to change network parameters and original programs, nor do they need to understand the details of the Profinet protocol. DTD418M can directly replace the wired Ethernet communication between PLCs, and realize wireless Profinet stably and conveniently. network.
Test equipment and parameters
Siemens PLC model: S7-1200 × 2 units
Wireless communication terminal: DTD418MA × 2 units
Master-slave relationship: 1 master 1 slave
Communication interface: RJ45 interface
Power supply: 12-24VDC
Transmission distance: 100 meters, 1KM
Wiring method▼
Use a communication cable, connect one end to the RJ45 interface of DTD418M, and the other end to the RJ45 interface of S7-1200.
Test steps:
1. Open the Portal software → Create a new project → Add two 1200PLCs (one as IO control device and one as IO device)
2. After the addition is completed, set the parameters of each PLC Ethernet
For the setting of the Ethernet interface parameters of the intelligent device, in addition to setting the Ethernet address, you also need to set the operating mode and transmission area. Set and update time. As shown in the figure below:
3. Simple I/O correspondence of the main program
4. Network configuration configuration
5. Download the program to 2 computers respectively Inside the PLC
Test method
Two PLCs are connected to the Datai Siemens PLC wireless communication terminal DTD418M through Ethernet cables. After connecting the antennas, power the DTD418M and PLC. When a signal is input to the I point of PLC No. 1, the corresponding Q point of PLC No. 2 will have an output signal. In the same operation, we can input a signal to point I of PLC No. 2. At this time, the corresponding Q point of PLC No. 1 will have an output signal. Data interaction between the two PLCs is completed through Datai DTD418M wireless transmission.