Diehl LoRaWAN CMi4160, User Manual

Page: 14 / 24

CMi4160
– LoRaWAN
®
Module
14 02/2021
An example of a telegram for message format JSON is presented below:
Figure 7: JSON message example
Scheduled mode
For message formats of type “Scheduled” (Scheduled – Daily redundant and Scheduled – Extended),
two types of messages will be transmitted from the module - a clock message and a data message.
The difference between the two is described in Table 8. A detailed description of the payload of the
clock message is provided in Table 9.
Message Time interval Description
Clock message Once per day The clock message presents the current time of
the meter. It can be used to verify that the clock
is correct and has not drifted more than
accepted.
Data message Determined by transmit interval
parameter. The actual meter data collected from the meter.
For more information, see Table 11 and Table
12.
Table 8: Clock message and data message
DIB Field Size Data type Description
0 Message
format
identifier
1 byte - 0xFA (=Clock message)
1 Date/time 6 bytes 32-bit binary integer
M-Bus type F 046Dxxxxxx = Valid date/time
message
346Dxxxxxx = Invalid date/time
message
Table 9: Payload, clock message
The clock message will be transmitted once every day and the data message at least (regulated by
transmit interval parameter or EcoMode) once every day. The transmit interval can only be set the
values listed in Table 10.
Note that although the meter readout will occur on top-of-the-hour, the data message will not
necessarily be transmitted at that exact time. The LoRa transmission will occur after a random delay
of 0-15 minutes to decrease the risk of collisions. The readout for the clock message occurs at a
random hour (00:00-23:00) at a random minute in the 35-45 interval and will be transmitted
immediately after readout.
When using message format S
cheduled
, the transmit interval cannot not be set to
higher than 1,440.
Parameter Values Unit
Transmit interval 60/ 120/ 180/ 240/ 360/
480/ 720/ 1,440 Minutes
Table 10: Transmit interval options for Scheduled message formats
Scheduled- daily redundant
The data message of
Scheduled mode-daily redundant
contains an accumulated daily energy field,
which is updated at 24:00 each day. In other words, depending on transmit interval settings and data
rate, the field will be included in between 1-24 telegrams per day. This will increase the probability of
the value being received. For example, if the transmit interval is set to “2”, the accumulated energy
read at 24:00 will be transmitted 12 times during the 24 next coming hours (every 2
nd hour).
{"E":12345678,"U":"kWh","ID":87654321}