User Guide

IoT into the Wild
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10. LoRaWAN Downlink Command
10.1 Set the Data Uplink Interval
(1) Using the Network Server’s portal or API to send downlink command, then the Node will
respond to the ack. The downlink command takes effect and responds the next time the
node uploads data.
(2) Downlink as follow:
0x00
0x89
0x00
prepareId_L
prepareId_H
duty_L
duty_H
crc-L
crc-H
0x00
Fixed field
0x89
Fixed field
0x00
Fixed field
prepareId_L
Command ID low byte, you can customize the values, it allows each command ID
to be the same
prepareId_H
Command ID high byte, you can customize the values, it allows each command ID
to be the same
duty_L
Data interval low byte, you can set the data interval, unit: minute
duty_H
Data interval high byte, you can set the data interval, unit: minute
crc-L
CRC low byte, it’s calculated by the CRC-16/CCITT
crc-H
CRC low byte, it’s calculated by the CRC-16/CCITT
(3) When you send the downlink command, the Node responds to the ack command.
0x00
0x1F
0x00
prepareId_L
prepareId_H
result
0x00
crc-L
crc-H
0x00
Fixed field
0x1F
Fixed field
0x00
Fixed field
prepareId_L
Command ID low byte, it is the same as the downlink command
prepareId_H
Command ID high byte, it is the same as the downlink command
result
If the downlink command is in force, it responds 0x01, else it responds 0x00
0x00
Fixed field
crc-L
CRC low byte, it’s calculated by the CRC-16/KERMIT
crc-H
CRC low byte, it’s calculated by the CRC-16/ KERMIT
(3) Use the FPort = 2
CRC Tool: https://crccalc.com/ , select the algorithm of CRC-16/KERMIT.