Converting an Modbus RTU protection relay (VIP410) to communicate measurements to client BMS by TCP using M221

Yarom · Monday

Hi,

I am almost done with the application.

I have a VIP410 protection relay with Modbus RTU. I am required to convert that and data regarding switchgear states to client BMS through Modbus TCP.

I have an M221. I configured the digital inputs and can read their states using Doctor Modbus (or any other Modbus application).

I configured on the M221 Modbus RTU IO Scanner with a set of addresses. I have 2 VIP410 units. Device ID 1 and 2. I am able to read on the PLC both. However, I cannot read more than just one register. I do not know what address I am supposed to read from.

This works. I am able to read in Machine Expert - Basic the current values on the registers I configured.

My question, plain and simple, what is the address that I should be reading in Doctor Modbus? I tried 100, there is nothing. I tried 1, nothing. I set both device channel details to be the same as I am to read the same registers from each device.

Here is the table I am referring to from the VIP410:

I set the channel to start with register 1024 and took 12 length for the number of registers.

I did the same for the Device ID 2.

Here is the reading by the PLC:

Here is what Doctor Modbus sees:

It reads the right current that I am injecting at register 1 which is (as I assume) 100.0.0 of the PLC.

I can I not find the one of device 2?

I continued with my test on device 1 and moved the injection to phase 2 of both panels. In the PLC I am able to read the phase 2 current at 100.0.1 but I cannot see it in Doctor Modbus. I am not sure of which address to read from.

What am I missing?

Thank you for the assistance.

Yarom

Bastian_Schmitz · Tuesday

Hi,

So far I see you write all values from the IO Scanner to the same %MW. Is the one value which you get correct? Did you use FC3 or FC4 in the channel configuration? Did you check to start at 1023 or 1025?

Some Devices start at Register 0 some at Register 1.

Did you check the status of the IOScanner ?

And finally you could do this easier. If you only need to convert Modbus RTU into Modbus TCP you could direct use TM172SIG. This need only be to configured via webserver as Gateway and then the BMS could directly read the RTU values via TCP.