Lobaro wMBUS-LoRaWAN, Руководство пользователя

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5. LoRaWAN Data Upload Formats
5.1. Status Packet
Port 1 In order to provide some information about the health & connectivity state of the
device itself, the device sends a status update at a daily basis. The status packet is sent
on the rst upload phase after activation of the device (after reboot) and then repeatedly in
every upload phase that takes place a day or longer after the previous status packet. It has
a xed length of 7 bytes. The battery voltages and ambient temperature are encodes as 16
bit integer using little endian encoding.
0 1 2 3 4 5 6
version v_bat temp
Figure 5: Bytes, port 1 Status Packet
name type description example
version uint8[3] Version of the rmware running on the device 1, 5, 1 v1.5.1
v_bat uint16 Battery voltage in mV 2947 2:947V
temp int16 Temperature measured inside the device in
1
10
C 246 24:6 C
Table 5: Fields port 1 Status Packet
We provide a JavaScript reference implementation of a decoder for this status packet on
GitHub
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, which can be used directly for decoding in The Things Network
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.
5.2. Data Packet
After each wMBUS collecting phase, all saved telegrams (up to 500 can be stored) will be
uploaded via LoRaWAN uplink messages as fast as possible. The received wMBUS telegrams
that did pass the congured white list lters will be uploaded without any modication in one
or more LoRaWAN messages.
If a wMBUS telegram is bigger than the bridge conguration parameter loraMaxMsgSize the
transmission will be done using multiple LoRaWAN messages. This parameter is limited to
50 bytes due to LoRaWANs maximum payload size restrictions. In case of telegram splitting
is needed the receiving backend application server as to reassemble the original wMBUS
telegram before decryption & parsing of the meter data. This is done by simply joining the
messages together in the order of receive.
The LoRaWAN port encodes identies a LoRaWAN fragment of the original wireless M-Bus
telegram. This way partial messages can be identied using the LoRaWAN Port:
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https://github.com/lobaro/ttn-data-formats/blob/master/wmbus-bridge/decoder.js
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The Things Network (TTN): An open source LoRaWAN network provider
see https://www.thethingsnetwork.org/
wMBUS over LoRaWAN Bridge 15