Reawakening old EmonPI

I am trying to set up my old EmonPI to monitor my solar PV at a new site. I put it into storage about 5 years ago, and hadn’t been actively using it for a while before then!

When I connect to the EmonPI using Chrome in Windows I get the following message:

settings.php file error

settings.php config file has new settings for this version. Copy default.settings.php to settings.php and modify the later.

To fix, check that the settings are set in settings.php or try re-creating your settings.php file from default.settings.php template

Without the GUI this not very techie is a bit lost! Do I need to access the EmonPI via the command line somehow?


My suggestion is to get a new SDCard, open the emonPi up and then start from scratch.

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Just check that it works on 433 MHz. This became the standard frequency in 2014, if you had your emonPi before then, it could be 868 MHz, in which case you’ll need to change the sketch that runs in the “emon” part to work at 868 MHz. (See 868MHz emonPi working with 433MHz emonTH?)
@borpin Is the latest OS compatible with an ‘old’ RPi?

Thanks Brian and Robert. I bought it in 2015 so processor speed shouldn’t be an issue. I had figured that updating the SD card was probably the way forwards, my main issue has been finding a working card reader so I can copy the up to date files onto it, as the two I have tried so far don’t seem to be working!

Do you mean that, or the Radio frequency? I was talking about the latter: Networking — OpenEnergyMonitor 0.0.1 documentation

Unless @andrew.neil.clark has a TX or TH as well, it makes no difference.

I’d be inclined to invest the few quid and stat with a fresh card. If it can’t read it it may be dead.

By ‘copy’ I presume you mean flash the new image?

Hi, yes of course you are right, it is radio frequency! And I did mean flash, I did say I was not-so-techy!
I have ordered a new card so fingers crossed.

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As Brian says, it only matters if you’re using the radio. If you’re not, it won’t stop the rest working if the radio module is set to the wrong frequency - it’s only listening.

Oh dear, I have corrupted the SD card I just purchased by not shutting down the EmonPi correctly.
I amtrying to flash the files back onto it using Etcher, but it keeps failing. I have tried reformating the card but it still fails. Any suggestions? What file format should I use? I am running Windows. Thanks!

I have an emonPi and an emonBase and neither has ever fried their SD card despite numerous power cuts etc.

Etcher doesn’t need the card to be formatted; can you give a bit more info about the error?

Thanks Christian.
The EmonPi booted succuessfully once, but then after I unplugged the power supply to move it it just keeps hanging on the message “EmonPi booting” (or words to that effect) - I have left it for 10, 20 minutes and it never gets beyond this point.
In Etcher, I have tried reflashing the latest image but each time Etcher runs a scan post flashing and says the flash has failed.

It is highly likely it was in the process of doing all the setting up - it does sevral reboots in the process (a RaspberryOS thing). You need to leave well alone for a while or plug it into a monitor so you can see when it has finished.

Did you actually try and connect to it from a browser? It does get stuck here on the display occasionally.

Not sure why Etcher will not flash. Try the Raspberry OS Flasher and see if that works. I’ve not used Etcher for a long time now.

OK so everything’s working now. I used the Raspberry Pi software to flash the image onto the card and it worked. The EmonPi then booted successfully and after a bit of ignorant fiddling in Emoncms I managed to get all the inputs reporting data.
Now I just have to figure out what additional hardware I need to properly monitor my two solar inverters - which are in different buildings but are connected to the same 3 phase supply. At the moment I have a pulse sensor and one CT sensor which I have attached to the neutral wire where it enters the building where the meter is located, so I can measure import at the meter and (hopefully) export to the grid.
Thanks for the help!

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If it’s a three-phase supply, all that will do is measure the out-of-balance current in the three phases – not a meaningful quantity in relation to your overall consumption.

With the demise of the emonTx4, the monitoring I’d recommend, if the inverters don’t or can’t provide what you need, is using 3-phase Modbus meters.