LeadStudio multi-machine interconnection can easily realize network communication among multiple PLCs. Compared with traditional PLC communication methods, its solution has the following advantages:
① It supports both serial port and network port communication. In network port mode, network configuration can be performed by scanning, so users do not need to configure communication separately in each PLC program.
② It enables network configuration and program to be independent of each other. In scenarios where multiple similar machines are interconnected, there is no need for each PLC to manage a separate program.
③ The configuration can be modified in the program, making network configuration more flexible.
④ It supports data interaction between up to 32 slave stations. In Ethernet mode, the communication time for a single station is 4ms.
⑤ Ethernet communication is based on the PLC's MAC address, so users do not need to set the IP address of each PLC individually, which significantly reduces the user's workload.
Version information
LeadStudio programming software version: V2.6.6.0 and above
PLC firmware version: 7905 and above
Operating method
This article mainly introduces the method of achieving multi-machine interconnection and communication by scanning configuration in Ethernet mode. For operation methods in other modes, please refer to the LeadStudio Programming Manual.
1. Add N_N_Station_Ethernet communication ports to all PLCs in sequence.
2. After the PLC network is connected, open the LeadStudio software and scan to configure the communication for multi-machine interconnection.
Refresh Mode: Determines the range of shared memory addresses for communication; the range is 0-3.
Total number of slave stations: Sets the number of slave stations in the network, with a range of 1-31.
Station Number: Sets the identification station number for different devices in the network. It cannot be repeated. 0 is the protocol master station. The setting range is 0-31.
3. After setting up, click "Download Configuration" to complete the network configuration.
Data interconnection methods
In a multi-machine interconnected network, each station is allocated a shared memory area, which is further divided into 32 smaller memory blocks based on the maximum number of slave stations supported by the network. Of these, one memory block can be used to write data to other slave stations, while the remaining 31 memory blocks can only be used to read data from other slave stations.
The memory areas occupied by various websites on the Internet are shown below (only a portion is shown; please refer to the LeadStudio programming manual for details):
Assuming the network has three PLCs, the MW500-MW503 of the PLC with station number 0 will write to the MW500-MW503 of station number 1 and station number 2 in each communication cycle, while MW600-M603 and MW700-M703 will read from the MW600-M603 of station 1 and the MW700-M703 of station 2, respectively.
The data interaction process between the three sites is shown in the following diagram:
Note:
① In reality, there is no master-slave distinction in the network. All stations communicate in the same way, with one block of memory used for writing data and the other 31 blocks used for reading data from other stations.
② The interconnection communication address can be changed by setting the refresh mode. For example, in mode 0, station number 0 is M500-M503, and in mode 2, station number 0 is M500-M507.
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