Seeking advice on PLC settings
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This post was last edited by hanhaigang128 on 2024-9-26 09:09. There is 1 PLC on site; the RJ45 network port built into the PLC is used for direct communication with the touch screen. The PLC also has 1 485 interface, and a serial server is installed on site to convert the Modbus RTU protocol into the Modbus TCP protocol, which is then transmitted over fiber optic cables to other systems for remote monitoring of the PLC. The 485 interface is connected to this serial server. Does the PLC need to be set as a slave in its underlying logic? Do Modbus device addresses also need to be fixed in the logic?
The PLC needs to be set as a slave because it has to receive Modbus commands sent from the serial server (which acts as the master). At the same time, the Modbus device address should be fixed in the PLC’s logic to ensure proper and consistent communication. .
It’s resolved now. Indeed, the PLC requires a Modbus address to be set; this address must match the one configured in the Modbus gateway (serial server). Communication has been established and data can be read normally. Thank you all
The baud rate, parity, and slave address all need to be set.
Yes, professional: handshake
All of these need to be fixed during programming; the PLC that is read must definitely be set as a slave