Modbus Meter doesnt read in, what is wrong?

sdg.marinusvz
2024-07-17 11:24

This post was transcribed from a support call

Good morning, I am linking a Kocos Modem to an Eastron meter as a 'Generic Modbus Meter'. I am trying to get the meter readings but haven't been able to. Please can you have a look and advise. Thanks. (server name and meter serial number redacted for this post)

sdg.marinusvz
2024-07-17 11:25

Do you get any reply from the meter on the Communication Monitor?

sdg.marinusvz
2024-07-17 11:26
Last Edited 2024-07-17 11:27

yes

This is the actual reading on the meter:

sdg.marinusvz
2024-07-17 11:33
Last Edited 2024-07-17 11:34

I see on your Meter Details screen that you've got a multidrop id of 005$3205$1, meaning:

Modbus note address of 5

Modbus Register address of 3205

0 - 2 Byte Integer

1 - 4 Byte Integer (big endian)

2 - 4 Byte Float (IEEE754)

3 - 4 Byte Integer (little endian)

5 - 8 Byte Integer (big endian)

6 - 8 Byte Integer (little endian)

7 - 8 Byte Integer (Schneider Int64)

4 - PowerCOM

I see you tell the system the format is 4 Byte Integer (big endian) (the normal length for values in the Modbus Register block is 2 bytes per address, so it reads registers 3205 and 3206 to get 4 bytes)

I see in the document you sent me (Eastron SDM230-2T Smart Meter Modbus Protocol Implementation V1.1) the following:
'All data values in the SDM230-2T smart meter are transferred as 32 bit IEEE754 floating'
so your specified data format is wrong.

sdg.marinusvz
2024-07-17 11:34

Therefore, go to Meter Details, and change your Multi-Drop id from
005$3205$1
to
005$3205$2

sdg.marinusvz
2024-07-17 11:35

Okay thanks, will do

sdg.marinusvz
2024-07-19 16:00

Ok, some additional information:

for this Eastron meter, it turns out the correct register to read for Energy Total (kWh) was 72, and NOT 3205.

sdg.marinusvz
2024-07-19 16:03
Last Edited 2024-07-19 16:04

It also turns out, you need to address the Input registers, and not the Holding Registers, so we had to change the code of the meter to be able to handle the alternative registers block.

We've also updated the Meter Details screen to give the customer an easier time of choosing things like register type and format:

You can now choose register type and register format with drop down selection lists.

sdg.matiaan
2024-08-21 12:08

for this meter, these settings worked for me

Tags: eastron

sdg.matiaan
2024-08-22 17:12

for the breaker load a modbus coil (File->New->RTUs->Generic Modbus Coil) (on the same modem as the Generic Modbus Meter)
and then add a Contactor to the Coil

Coil Address 0 works at the moment (although I suspect its because the current firmware does not look at the coil address, it should be 0xFD00 I think)

Modbus address is of course the same as the modbus address for the meter.

sdg.matiaan
2024-09-02 14:10

Eastron SDM530C 3 Phase Meter contactor has this setup:

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