CMi6160
User’s Manual English
CMi6160
User’s Manual English
page | 24 (38)
[2022-10]
v1.4
Field
JSON key
Energy unit
U
Volume
V
Volume unit
VU
Power
P
Power unit
PU
Flow
F
Flow unit
FU
Forward temperature
FT
Forward temperature unit
TU
Return temperature
RT
Return temperature unit
RU
Error flags
EF
Tariff 1 Energy*
T1
Tariff 1 Energy unit*
U1
Tariff 2 Energy*
T2
Tariff 2 Energy unit*
U2
Tariff 3 Energy*
T3
Tariff 3 Energy unit*
U2
Missing time*
MT
Missing time unit*
MU
Table 8: Payload, JSON encoded message
*
Only included in the extended message
.
Example payload, JSON:
{
"TS":"2019-11-28T20:39Z",
"ID":87654321,
"E":12345.678,
"U":"MWh",
"V":3456.7,
"VU":"m3",
"P":5012,
"PU":"W",
"F":212,
"FU":"l/h",
"FT":80.3,
"TU":"C",
"RT":53.8,
"RU":"C",
"EF":"0x4012"
}
7.4.2.3
SenML/CBOR
For battery-powered devices it might be necessary to send several measurements in the same UDP
frame to save energy. In order to achieve this SenML RFC 8428 - Sensor Measurement Lists (SenML) +
CBOR RFC 8949: Concise Binary Object Representation (CBOR) is used to define a measurement list.
The idea is to send a list of measurements, where the first entry contains the base time for all the
readouts (which only need to specify an offset) and the meter id shared by all readouts. The other
records in the list may contain fewer readout fields to save space. The format allows sending all the data
for every readout, in which case the save (in terms of bytes) is smaller and lies in that fewer telegrams
are sent, some data needs not be transferred for every reading (like meter-id) and timestamps can be
