1. On-site application: Modbus485 to Profinet gateway is applied to the PLC control system of a steel rolling company. In this system, Siemens PLC (S7-1200) acts as the Profinet master station, the high-end high-precision temperature controller TTM509 acts as the Modbus slave station, supports Modbus485 communication, and BX-601-PN, the Modbus485 to Profinet gateway of Bexun Technology, acts as the two The bridge between them realizes the monitoring and data collection of the thermostat by PLC;

2. System requirements: monitor 10 sets of thermostat systems through Siemens S7-1200PLC. Among them, the communication baud rate required by each thermostat system is different;

3. System implementation: According to the user’s on-site requirements, each Modbus-to-Profinet gateway is connected to three sets of thermostat systems, (the baud rate of each Modbus-to-Profinet gateway on the serial port side should be set to match the connected temperature controller through the configuration software. The baud rate of the serial port of the controller is consistent), the Profinet port of the Modbus to Profinet gateway is connected to the Profinet bus network (Siemens S7-1200 PLC), and the 485 port of the Modbus to Profinet gateway is connected to the 485 port of the thermostat (according to the panel or instruction manual Wiring), and then map the data collected by the thermostat to the input and output mapping area of ​​S7-1200PLC through the Modbus-to-Profinet gateway, so as to realize the real-time monitoring of 10 sets of thermostat systems on site by one PLC, among which: BX-601-PN Wide range of applications, all devices with Modbus RTU/ASCII (RS485) interface can use this product to realize the interconnection with fieldbus Profinet devices, and quickly realize Modbus RTU/ASCII to Profinet; the application is simple, free configuration software is provided, and the operation is simple , can realize connection and communication in a short time; Modbus side supports Modbus master/slave function;

4. TTM509: High-end high-precision temperature controller, dual-channel input can be used for cascade control, remote SP setting, and position proportional control. Sampling period 0.05s, accuracy 0.1%, 5-digit display, support Modbus (RS485) communication, serial communication baud rate supports 19200, 9600, etc., data bits are 8 bits, no parity check, stop bit is 1;

5. The system structure diagram is as follows:

6. PLC configuration: Import the GSD file of the Modbus to Profinet gateway into the PROFINET master station configuration software, and the Modbus to Profinet provides the GSD file, which can correspond to the Modbus master station and Modbus slave station functions respectively. Import the GSD file in the hardware configuration of Step7, drag the Modbus-to-Profinet gateway module to the PROFINET bus, and then perform configuration settings. After compiling and downloading, the communication test can be carried out. As shown in the figure below: Multiple Modbus-to-Profinet gateways are connected to the Profinet bus configuration (one Modbus-to-Profinet gateway is connected to a set of thermostat system), first drag the Modbus-to-Profinet gateway to the network, and then drag the data block Drag it to the slot at the bottom left of the configuration software. Double-click the gateway to set the basic parameters of the device, including IP address and device name, as shown in the figure below:

7. Open the property device page of the data block, configure the Module according to the actual requirements of the project, and only need to calculate the total number of input and output of the connected device as shown in the figure below:

8. After setting, download the configuration to the PLC gateway configuration: Open the gateway configuration software to set Profinet and Modbus. Click the new icon to select PN2MRM3;

9. Set the IP address and device name of the Modbus-to-Profinet gateway, which must be consistent with the PLC configuration;

10. Set the 485 parameters of each channel;


11. Right-click to add station number and function code;

12. Take the 03 function code as an example. If the address in the manual of the slave station is in hexadecimal, it can be converted into decimal and directly filled in the starting address. If the address format is 40001, 40002, then directly fill in 1 and 2. If the device address has an offset, the address will be reduced by 1;

13. The memory mapping address corresponds to the IQ start address of Botu. The input starts from 0, and the output starts from 1500;

14. Application summary: By using BX-601-PN, users can quickly and conveniently connect multiple Modbus485 devices on site to the Profinet network, onlyThe Modbus-to-Profinet gateway needs to be simply configured to realize centralized monitoring and data collection of field devices by PLC.

Reviewing editor: Tang Zihong

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