P3U30 energy reading from modbus connection

[Mentor]

Hello,

I am connection a schneider protection relay P3U30 with a Siemens SCADA (WinCC) through modbus tcp.
As per communication setting, I can read values like voltage, current, power ect. But I have a problem with reading of the Energy values (adress 402026).

Energy calculation mode is set to Fundam, is that ok?

In the Wincc, tag setting is: "signed 32-bit value" - "LongToSignedDWord" address: 3x402026.

Here I can read some values, but they are giving me rong measurment and is not the same value as it is in the relay. (reading from eSetyp Easergy Pro/measurments/energy/Exportet energy.
I tried to read this address from "modbus poll" software with different addresses and types, but never get the right number.

Please suggest me how to solve this?

Thanks and best regards.

[peer.mydeen · Accepted solution]

Hi,

The format you calculating is wrong

The format is 

U48-M10k-21-65

U48-M10k-21-65

A 48-bit unsigned value returned in three consecutive 16-bit registers. R3*10,000^2 + R2*10,000 + R1, where R3 is the last register and R1 is the first register. Each registers range is 0 to +9,999

[Mentor]

Thank you MpKpeer,

As we do not have any option in WinCC for 48-Bit Tag. I did it as you suggested by creating 3 tags 16-bit and then with a script I did the calculation and sent the result in another tag 64-Bit.

 I can read the correct value now.

[Nhuautomation]

hello i cannot read device p3u30 to PLC s7-1200 by Modbus TCP

I test by software Modbus Poll then i see address but i convert the PLC no read

Can you help me

[Nhuautomation]

hello,

I cannot read register device p3u30 to device s7-1200. i read the document the register 402009 but in the PLC I cannot see.

I test by software Modbus Poll then  I see register device P3u30 repply

Please suggest me how to solve this?

Thanks and best regards.

[Mentor]

Hello,
Have you tested your PLC program with other devices? I means is the PLC configurated correctly?
In the PLC, the modbus address is one number bigger. So please try the address 402010 with data length 2.