Using multiple PM5320 devices via Modbus TCP – how to distinguish between devices?

[Phil_38552]

Hello,

I am currently testing a PowerLogic PM5320 device, which is directly connected to my PC via Ethernet. Using a Modbus test tool (Baseblock ComTest Pro), I’m able to successfully read data from the holding registers via Modbus TCP.

In the final application, however, multiple PM5320 devices will be used in the same network. A Modbus TCP client (Anybus Communicator – Modbus TCP Client to PROFINET IO Device) will be responsible for cyclically reading data from all connected PM5320 devices.

My key question is:

👉 How can the Modbus TCP client distinguish between the individual PM5320 devices in the network?
As far as I understand:

• The Unit ID for Modbus TCP is fixed to 255 and

• It cannot be changed via the front panel or ION Setup.

I couldn’t find any reference in the manuals indicating that the Unit ID can be configured for Modbus TCP operation.
Does this mean that the only way to distinguish between multiple devices is by assigning unique IP addresses to each PM5320?

Or is there any method to configure a different Unit ID per device, to allow multiple devices to be queried from the same client?

I would appreciate any official guidance or recommendations, as this question is crucial for planning the communication setup in our project.

Best regards Phil

[akash_das · Accepted solution]

Hi@Phil_38552 If you're trying to identify multiple PM5320 meters on a network, using their IP addresses is the standard method. Any Modbus TCP client can poll each meter using its unique IP. The Unit ID remains 255 for all, but it doesn’t matter because the IP is different. This is the recommended and simplest solution.

[Phil_38552]

Hi @akash_das ,
thank you for the quick and clear reply!

That exactly confirms what I was assuming, and it's good to know that identifying the PM5320 meters via their IP addresses is the recommended approach.

I’ll proceed with the setup accordingly.

Thanks for your support!