How can i make control field one byte hex value?????

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By chang2 , 14 October, 2018

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General discussion

I am using obis code to construct a dlms frame.

our test device is NJ12-210-GEN made by NamJun Co,Ltd in korea

we send broadcast packet by using python pyserial module, but we don't know how control field is set..

For example, we want to know date/time information, then we send dlms data included OBIS Code(08 00 00 01 00 00 FF)

In this case, full dlms data are set to "7E A0 1A 02 FF 23 54 DA 6D E6 E6 00 C0 01 81 00 08 00 00 01 00 00 FF 02 00 65 D7 7E"

when i translate they by using DLMS Translator, i can get xml code

<HDLC len="25" >
<TargetAddress Value="255" />
<SourceAddress Value="17" />

<FrameType Value="54" />
<PDU>
<GetRequest>
<GetRequestNormal>
<InvokeIdAndPriority Value="129" />
<AttributeDescriptor>

<ClassId Value="8" />

<InstanceId Value="0000010000FF" />
<AttributeId Value="2" />
</AttributeDescriptor>
</GetRequestNormal>
</GetRequest>
</PDU>
</HDLC>

But I don't know how Frame Type(A.K.A control field, 0x54) is set.

please teach me how to make control field byte...

How can i make control field one byte hex value?????

Hi,

HDLC frame is described on the standard. Its value is changed all the time. I believe that the best and fastest way is if you use our open source libraries to read your meter.

BR,
Mikko

not need to use your library…

not need to use your library just share how we make control frame for any hex string?

Hi, DLMS is a complicated…

Hi,

DLMS is a complicated protocol and the control frame is part of HDLC framing.
It's not possible to describe shortly. You need the "IEC 62056-46 Data link layer using HDLC protocol" standard to handle the HDLC frames.

https://gurux.fi/DLMSCOSEMFAQ

BR,
Mikko