Wireless M-Bus Range Extender /
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User Manual Version 1.0
Page 25 of 32
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Packet Decoding and Reassembly on Application Server Side
Due to the fact that one Wireless M-Bus packet may not exactly fit into one LoRaWAN packet a tiny
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In general there exist two possibilities:
A Wireless M-Bus packet is spread over multiple LoRaWAN packets
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A LoRaWAN packet can contain several Wireless M-Bus packets
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Both possibilities must be handled by the Transport Protocol. Therefore on the receiver side it could happen that:
A Wireless M-Bus package must be assembled from several LoRaWAN packets
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A LoRaWAN packet could consist of several Wireless M-Bus packets
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The following description explains the reassembly of Wireless M-Bus packets on server side.
The LoRaWAN packets must be collected until the sequence byte indicates the final segment
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. The most significant bit in the control field is
set to "1" in the final segment. The 7-Bit Sequence counter of the
is always be incremented by one. The counter wraps
LoRaWAN packet
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around from 0x7F to 0x00.
Example code snippets for uploaded W
data
ireless M-Bus
. A chirpstack server
The example code is developed according to a chirpstack server data format
offers the option of forwarding received
packets of an application directly via HTTP POST method. Our example
is about extracting and processing the important information
code
.
from this forwarded json data
Forwarded json data could look like:
