Update a new emon pi with Build: 18-Jun 2015


Update a new emon pi with Build: 17-Jun 2015


I have just installed a emonpi and a emontx3.
However, there is much in the startup manual that I can not get to vote.
Not least update, and Power Down, does not work.
The unit came with a emonPi Build 17Jun 2015 and it seems like a very old firmware.

How can I most easily opdatet it to V2.5 or 2.6?

There is no Update menu in the device.

I would recommend updating to the latest pre-built Raspberry Pi image: emonSD-03May16.

You will need to download this image, then flash to a fresh SD card. Instructions are on the download page. You will then be running Emoncms V9 and can the follow the setup guide:

Subsequent updates can be done using emonPi update in Admin > Update emonPi in Local Emoncms

Hi Glyn

Thanks for help with the startup of emonPi.
Now I’m running with the latest software, and it looks something different and better.

However, I have wondered about the VRMS value is well above the actual voltage (260.6V) against the measured value: 232 V. Is it normal that it should be adjusted via emonhub?

node name = emontx3
names = Power1, POWER2, Power3, POWER4, Vrms, temp1, temp2, temp3, temp4, temp5, temp6, pulse
datacodes = h, h, h, h, h, h, h, h, h, h, h, L
scales = 1,1,1,1,0.01,0.1,0.1, 0.1,0.1,0.1,0.1,1
units = W, W, W, W, V, C, C, C, C, C, C, P

I read somewhere on the forums that an update to the latest firmware version solved the problem of error vrms display, but it does not seem to be the case.

Can there be a need to update the firmware in emontx3 ?

Best wishes

Hi Sune,

Good work getting up and running, it looks like everything is working correctly. Your emonTx will have the latest firmware.

What are you using to cross-check the emonTx voltage? You can check is that the emonTx is not set to USA calibration, both DIP switches should be off. See emonTx DIP switch config.

The VRMS calibration can be tweaked by changing the Vcal value then recompling and uploading the code using Arduino IDE:


The calibration value 268.97 should be correct for the UK ac adapter, if you have the Euro adapter (both from the shop), the calibration value should be 260.0

But that does not explain the >12% difference between your measured and reported values. I suggest that, if possible and you have the appropriate test instruments, you should do the full calibration procedure.

You are using the Euro ac adapter (Ideal Power 77DE-06-09) ?