The LTC2-SI stores all record logs on the sensor. In the case that it loses connection to the gateway the missed records must be retrieved manually from the sensor. This can be done by following these steps:
User can get the start and end date and time from link: https://www.epochconverter.com/
Use the 'Human date to Timestamp' to retrieve the start and end date in Epoch format.
The Epoch time must then be converted to hexadecimal: https://codebeautify.org/decimal-hex-converter
For Example:
A1 - Command code for datalog poll
674C4000 - Start timestamp (Dec 1, 2024)
6751A3FF - End timestamp (Dec 4, 2024)
05 - Uplink interval in seconds (sensor will send one packet every 5 seconds)
Combine into one string: A1674C40006751A3FF05
Send Downlink via ChirpStack
Log into ChirpStack web interface
Navigate to your LTC2-SI device:
Applications → QTRACA→ Devices → [Your LTC2-SI]
Go to the Queue tab
Enqueue the downlink:
FPort: 2
Payload format: Select Hex
Payload: A1674C40006751A3FF05
Confirmed: Optional (recommend checking this)
Click "Enqueue"
Wait for Response
The downlink will be sent during the next uplink window.
After your sensor sends its next uplink, it will receive the downlink command.
The sensor will then start uploading stored data entries.
You'll see multiple uplinks coming in every 5 seconds (or whatever interval you specified)
Example
Let's say you want data from December 1-3, 2024 and are in the NZDT timezone (UTC+13):
bash
December 1, 2024 00:00:00 NZDT = Nov 30, 2024 11:00:00 UTC
December 3, 2024 23:59:59 NZDT = Dec 3, 2024 10:59:59 UTC
Using UTC times:
Start: 1732963200 = 0x674A6C00
End: 1733224799 = 0x674E85FF
Final payload:
A1674A6C00674E85FF05This will retrieve all readings between those dates, sending them back every 5 seconds.