CMi6110
User’s Manual English
CMi6110 User’s Manual English
page | 31 (42)
[2022-10]
v1.3
35
# Time "2019-11-28T19:00Z"
36
08 # Key 2 = 8 = Data value : 1 (fixed)
37
46 # Value 2 = Byte array, length 6 : 1 (payload < 24)
38
0406F24FBC00 # M-bus record with one DIB: : variable
39
# Energy = 12341,234 MWh
40
Sum : X * (7 + (1) + payload2 size)
41
42
Total: 22 + (1) + payload 1 + 8 + X * (7 + (1) + payload2 size)
Given the fixed sizes above using M-Bus and assuming payload is < 256 bytes for the first record and <
24 for the subsequent records, the total size is:
29 + pa 6 + X * (7 + payload2)
Some example sizes:
payload1
payload2
Total
#records
Total
size
33
6
24
367
33
33
12
508
36
32
24
968
Validators
http://cbor.me/ - Validator for CBOR, does not understand SenML or M-Bus
Noted a small bug in the hex interpretation of negative numbers, the diagnostic window seems
correct though.
Configuration
SenML/CBOR is to be considered a
message encoding
. It defines how the messages are encoded, but
not the actual contents of the messages (which fields from the meter are included). SenML/CBOR/M-Bus
is one such encoding, but there could be several based on this SenML/CBOR specification and the
encoder version field
above defines exactly which type and version is used.
The contents of the message are defined by the
message
format. The message format sets which fields
are to be included in both the first and the subsequent records of the SenML pack.
The number of records included in a pack is set by the readout and transmit intervals. See Scheduling
Readouts for more details. If the readout interval is 120 minutes and the transmit interval is 1440 minutes
12 readouts in total will be included.
Message Size Restrictions
Each product may have different maximum payload sizes in a single telegram. Also depending on
configuration (DTLS or not for instance) the net payload size may vary. Therefore, the device shall “fill up”
as many telegrams as required to send the data. It is for the user to define a configuration that gives a
reasonable tradeoff between power consumption (send fewer telegrams) and functional requirements
(much data is sent).
If a device is configured using a
Message Format
and many readouts the data may not fit in a single
telegram. In such cases multiple telegrams shall be sent and each telegram shall be fully self-described,
i.e., contain Meter ID, timestamps etc.
