Good day,

In our client facility, we have 3 ION 7650 Schneider Power meters which are currently being polled by an RTAC 3555 via Modbus TCP/IP. Now, we would like to connect these 3 Power Quality meters to another system (Modbus master) via their RS485 interfaces in a daisy-chain fashion.

Do these meters support multiple polling from more than 1 modbus "client" on different interfaces?

 

Ehh, you just told that you currently poll them with Modbus TCP, that is an ethernet connection, not a 3-wire RS-485 connection. That is another electrical interface and that is called Modbus RTU.

Please check the documentation of your power meters if they (can) support Modbus RTU RS-485

 

In general, any device that has both an Ethernet port and an RS-485 port should allow communication on both simultaneously. It should be stated in the device's user manual if this is not the case.

Therefore, you should be able to communicate Modbus/TCP via your RTAC to the meters' Ethernet ports and also communicate Modbus RTU from the other system to the meters' RS-485 ports.

Also, so you are aware, you can have multiple Modbus/TCP clients communicate to a single Modbus/TCP server. So, for example, if your other system was instead Modbus/TCP, not Modbus RTU, you could have both the RTAC and the other system communicate Modbus/TCP simultaneously to the ION meters. Note though, while in general, most Modbus/TCP server devices support multiple clients, there may be some devices that do not. You would need to confirm this with the manufacturer.

 

Good advice. Some Modbus TCP connections can use multiple clients, but not always......you have to test that yourself.