Let’s say your IoTa burns to the ground and you change an SD card to move on. Is there any way to extract the data from the older unit? I presume measurements are stored on the iotalog.log which are used for visualizing purposes in graph+. Is there something equivalent for accessing the logs once extracted from the SD?
Thanks in advance,
Elias
If the SDcard fails, the datalogs are usually toast. If the unit fails for another reason, simply moving the card to a new unit will preserve all of the history.
If the datalogs are damaged, they should be deleted and there is no way to recover the lost data. I don’t have any software that can read a datalog other than the IoTaWatt firmware, but it would be possible. First you would need to understand both the physical (little endian) format and then the logical organization and format of the data. It’s not published anywhere but available in the code if you read c++.
Up to one year of 5 second data is in /iotawatt/iotalog.log. Once full, it wraps around and chases its tail, so the beginning must be located by examining the contents. IoTaWatt does this at startup so the code is there.
The /iotawatt/histlog.log is the same data at 1 minute intervals. The entries are identical to the corresponding entries in iotalog.log except for a different serial number. In context they contain the accumulated Volt-hours, Watt-hours and VA-hours since unit commissioning. So, along with any entry, from either log, the average measured Watts, Wh, Volts, Hz, VA, Amps etc for the interval of time between the two entries can be determined.
Thanks, as you know I am using the IoTaWatt for a research project but most of the values I am interested in (power, current, pf) I just push to influx. I have two publications submitted mentioning the IoTa, I will send them over once they are out.
Cheers,
Elias