Unable to read data from smart meter (GPRS)

Hi Mikko, thanks for your quick reply.

I was trying to attach the connection to the sender and then read the meter, but I got an error saying "ipSettings cannot be null" or something similar (it was a few days ago).

I gave up on that approach and started reusing the connection. Now, I’m trying to read the Clock object to test if it works, but I can’t understand the error.
This is my code at this moment:

GXDLMSData obj = new GXDLMSData
{
LogicalName = logicalName
};

byte[][] requests = client.Read(obj, attributeId);

//byte[] responseBytes = Encoding.ASCII.GetBytes("OK");
//connection.Send(responseBytes, responseBytes.Length);

// REUSE EXISTING CONNECTION TO SEND REQUEST
foreach (var request in requests)
{
Console.WriteLine($" Sending request: {BitConverter.ToString(request)}");

connection.Send(request, request.Length);
}

LogicalName will be "0.0.1.0.0.255" and attributeId is 2.

- I am getting the message with the instant values, and then I need to send all requests (there might be more than 1. So you are saying I need to send the next request after I receive the previous one's response?). I set properly the keys and system title so I am able to translate it thanks to translator class.

When sending the request for the Clock object, this is what I send and what I get:

?? Requesting OBIS 0.0.1.0.0.255, Attribute 2...
?? Sending request: 00-01-00-01-00-01-00-14-C8-12-20-00-00-00-00-71-A9-16-28-6F-B6-34-7B-F9-E0-B0-E9-AE

Received Raw Data: 00-01-00-01-00-01-00-03-D8-01-02

When I try to translate the request within Gurux DLMS Translator tool, I get:

BlockCipher key: 83 1A 17 11 6C 24 9E 49 44 52 ED DA AD 33 E0 A1
Authentication Key:83 1A 17 11 6C 24 9E 49 44 52 ED DA AD 33 E0 A1
1: 00 01 00 01 00 01 00 14 C8 12 20 00 00 00 00 71 A9 16 28 6F B6 34 7B F9 E0 B0 E9 AE
<WRAPPER len="14" >
<SourceAddress Value="1" />
<TargetAddress Value="1" />
<PDU>
<!-- Invocation Counter: 0 -->
<!-- Decrypt data: 4C 41 C2 F5 3E 6E CD A6 EE B6 A9 0A DB
# Decrypt failed. Different block cipher or authentiocation key is used to generate this.
-->
<glo_GetRequest Value="200000000071A916286FB6347BF9E0B0E9AE" />
</PDU>
</WRAPPER>

,which is strange, because it mentions that the block cipher to decrypt it is different...

Any ideas on what might be causing this?

Thanks again,

Carlos.

Hi Mikko,

I have asked the Manufacturer (Sagemcom) whether we need to initialize the connection by sending this AARQ request.

Meanwhile, I have been trying to send a AARQ request and I got the same response as I do when trying to read the Clock object. This is what I got now:

?? Sending AARQ request: 00-01-00-01-00-01-00-3F-60-3D-A1-09-06-07-60-85-74-05-08-01-03-A6-0A-04-08-00-00-00-00-00-00-00-00-8A-02-07-80-8B-07-60-85-74-05-08-02-00-BE-17-04-15-21-13-20-00-00-00-00-B0-A8-D7-28-68-E8-2B-1C-F8-82-51-B6-51-24

and response:
Raw Data: 00-01-00-01-00-01-00-03-D8-01-02.

- Regarding the system title, what I do is setting the Ciphering properties (the ones I use for translating the first UDP message I get):
1. System title as the server system title
2. BlockCipherKey - the meter key
3. AuthenticationKey - same as the meter key

Another question came up to my mind: When ciphered communication with the meter, the system tytle is included in the message, right? So, when I create the request that I am sending to the meter, is it being ciphered?

byte[][] requests = client.Read(obj, attributeId);

Thanks Mikko!

Hi Mikko,

We just got a response from the client confirming we don't need to send the AARQ as there is a pre-established association.

Thanks for your help. I'm able to send and receive a valid message for a Clock request.

Carlos.