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RS485 Connection Between Custom PLC and TP1200 Comfort HMI

7/23/2025 3:50 PM	Rate (0)
AutoGen_7586364 Joined: 2/13/2025 Last visit: 7/24/2025 Posts: 1 Rating: (0)	Dear Sirs, We are using our own PLC, which supports Modbus RTU over RS485, and we would like to connect it to a TP1200 Comfort HMI. We have configured the communication settings on the HMI to use Modbus RTU. However, we are uncertain about the physical RS485 wiring. Could you please advise on the following: Can we connect the RS485 A+ and B- lines directly to the HMI? If so, which specific pins on the TP1200 should be used for the RS485 connection? Alternatively, is an RS485 adapter required? Can we use the 6AV6 671-8XE00-0AX0 (RS422/RS485 communication module) for this purpose, and if yes, which pins correspond to A+ and B-? Your guidance on the correct hardware setup and wiring would be greatly appreciated. Best regards,

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7/31/2025 6:10 AM	Rate (0)
Murof Platinum Expert Joined: 8/3/2009 Last visit: 9/2/2025 Posts: 16290 Rating: (1930)	Hello AutoGen_7586364 you can have a look in the manual, there you will find information about the tested communicaitno cables for the Modbus RTU communication: https://support.industry.siemens.com/cs/ww/en/view/109813307/111029454347 perhaps it helps Bye Murof
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