DLMS in Python

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DARCARPER
DLMS in Python

Hi.

I have an application in python that uses an optical probe to communicate with a meter. I identify with the emter correctly. The problem comes when I want to ask for data. I have these frames taken from the gxdlms:

16:45:58 Read object type Data index: 1
TX: 7E A0 19 03 21 "FE" "0F" "D4" E6 E6 00 C0 01 C1 00 01 00 00 60 0A 07 FF 01 00 2C 9A 7E

16:45:58
RX: 7E A0 18 21 03 1E BA 89 E6 E7 00 C4 01 C1 00 09 06 00 00 60 0A 07 FF AB A3 7E

16:45:58 Read object type Data index: 2
TX: 7E A0 19 03 21 "10" "7F" "DA" E6 E6 00 C0 01 C1 00 01 00 00 60 0A 07 FF 02 00 44 B0 7E

16:45:58
RX: 7E A0 12 21 03 30 68 9D E6 E7 00 C4 01 C1 00 11 82 01 EA 7E

the bytes between quotes are the ones that change and do not know what criteria. Can you help me or tell me where I can find out?

Thank you

Kurumi
Kurumi's picture

Hi,

That is HDLC Control Field. There is a counter that is changed every time when you send and receive data from the meter.

BR,

Mikko

________________________________________
Mikko Kurunsaari
Gurux Ltd
http://www.gurux.fi

DARCARPER

But is it a random code or does it have something to do with something?

Thanks

Kurumi
Kurumi's picture

Hi,
It's not a random code. Send and receive sequence number is there. Meter don't reply if it's wrong.

BR,
Mikk

________________________________________
Mikko Kurunsaari
Gurux Ltd
http://www.gurux.fi

DARCARPER

and how can I know what code is in each moment?

Kurumi
Kurumi's picture

Hi,

You can get more info from here:
https://en.wikipedia.org/wiki/High-Level_Data_Link_Control

I have to say that HDLC framing is not very easy.

BR,
Mikko

________________________________________
Mikko Kurunsaari
Gurux Ltd
http://www.gurux.fi

DARCARPER

I read the article and finally I have running my program in python.

Thank you so much for everything