Do you see the LED flashing now it is working again? This is important to confirm the significance of not seeing it when no data was being passed, ie does the LED work normally? is it bright enough to see? are you familiar its location? etc
If the LED stops flashing it signifies it is no longer receiving valid packets so there will be nothing to pass via the serial connection. Valid in this instance means passed CRC checks (ie no corrupt, partial or weak packets) and the group Id matches.
You don’t say what you setup is, for now I assume the latest emonSD image. When you do the automated update in stops emonHub and restarts it after the update, this will reset the serial port, which will reset the AVR on the RFM2Pi. So if the device has stalled due to a bad connection, power glitch or had it’s settings altered, resetting it would get it started again, using the default settings.
Which “CSV’s” to you mean? Are you referring to the PHPfina/PHPfiwa/PHPtimeseries feeds? If you are using fixed interval feeds the absent values will be null values as the timestamp is determined by the values position from the start of the file, so what you see sounds correct if there was no data coming in.
Q1 Yes there is the eventp processes in emoncms and/or you can set something up in node-red.
Q2 The emonhub.log is alway’s the best source of info for this type of issue, although the emoncms based log viewer is somewhat limited. If you can ssh into the emonbase and look at /var/log/emonhub/emonhub.log (there will also be some rotated out files eg emonhub.log.1 you can look at if the emonbase has been running for a long period, but unfortunately these files are lost on a reboot due to being held in RAM on the read-only OS. You can use “less” or “nano”(a bit slow with large files) to view the whole logfile.
At this stage it is a bit of a guess but perhaps a valid one, but there is/was an known issue where the RFM chip locks out very occasionally on rfm2pi and emonpi devices. although it has not been “fixed” it is no longer apparent in the emonPi firmware due to a temporary fix where it constantly resets see the RFM69Pi stops updating/freezes thread for links to the old forum where the most poignant info is, there are at least 2 very long threads on the old forum about this so issue so I would wait and see if it reoccurs and confirm the LED flashing (unless you are positive it stopped flashing) before embarking on the long read.