SNRM byte mening

By avietri , 2 December, 2025
Forums
Gurux.DLMS

Hi, I am newbie with DLMS. I am testing Gurux.DLMS.Python and I am working with a meter simulation software. I am able to use the Gurux.DLMS.Client.Example.python giving the command "main.py -S /dev/ttyS0 -c 16 -s 1 -a None" and the simulator works fine. When I sniff the frames, at first step the python code send the SNRM frame:

7e 0a 07 03 21 93 0f 01 7e

the simulator answers with UA response

7e a0 20 21 03 73 73 98 81 80 14 05 02 00 80 06 02 00 80 07 04 00 00 00 01 08 04 00 00 00 01 ce 6a 7e

I don't understand the meaning of bytes 0f 01 in SNRM frame, could you explain please? Are not CRC bytes.

Thanks in advance

avietri

7 months 3 weeks ago

Which CRC algorithm is used? Does the calculation done only on this bytes 0a 07 03 21 93 ?

Thanks in advance

Kurumi

7 months 3 weeks ago

H,

All this is explained in the DLMS standards. I believe it's easier if you read them, because DLMS is quite a complicated protocol.

BR,
Mikko