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How to Configure WinCC v7.4 to Sequentially Poll Multiple Modbus RTU Devices via a Single Modbus TCP Connection

4/29/2025 1:51 PM	Rate (0)
AutoGen_2978186 Joined: 12/9/2024 Last visit: 5/8/2025 Posts: 2 Rating: (0)	Hello everyone, I'm working on a WinCC v7.4 SCADA project and need help configuring Modbus communication. I have a ComAp InternetBridge-NT device connected via RS485 to 4 power meters (Modbus RTU slaves). The IB-NT acts as a Modbus TCP gateway, but it only allows one Modbus TCP client connection at a time. I want to connect my WinCC SCADA system to the IB-NT and read data from all 4 meters. Each meter has a unique Modbus RTU slave address. Since I can only use one TCP connection, I need to configure WinCC to poll the 4 Modbus slaves sequentially through this single connection. Has anyone done this before or can guide me through the setup? I'm especially interested in how to configure the channel, device, and tag addressing to make this work.

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5/2/2025 12:29 PM	Rate (0)
Murof Platinum Expert Joined: 8/3/2009 Last visit: 9/5/2025 Posts: 16349 Rating: (1931)	Hello AutoGen_2978186 I have never done this but perhaps this old FAQ can help for basic settings? https://support.industry.siemens.com/cs/de/en/view/37885119 Bye Murof
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5/5/2025 12:12 PM	Rate (0)
AutoGen_2978186 Joined: 12/9/2024 Last visit: 5/8/2025 Posts: 2 Rating: (0)	Hi Murof, Thank you for your response. I reviewed the document you shared in the post. However, it describes a standard setup with one master and one slave. In my case, the scenario is different, as there are multiple slaves sharing the same IP address, which makes it a unique situation.

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5/12/2025 8:12 AM	Rate (0)
msgsadek Bronze Member Joined: 8/12/2016 Last visit: 9/5/2025 Posts: 108 Rating: (3)	Any Updates for the issue or any workaround to solve it?

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