Welcome, Hans, to the OEM forum.
There can be two reasons for that:
- The baud rates do not match,
- The data being sent from the emonTx Shield is not in the format that the ESP8266 expects.
The data format looks to be correct for our software running in the esp8266, however unless you have our software in your ESP8266, I cannot be certain that it will be in the correct format.
If you are using the 3-phase PLL sketch, the latest version to use is here: Update to 3-Phase PLL sketch - #22 by Robert.Wall
All you need to do to disable the radio is not define “RFM69CW”, and define “EMONESP” instead. That will switch the the output to the correct format.
You must read the documentation that comes with the sketch for all the other settings, calibration and installation instructions.
The sketch (I presume you will need the 3-phase sketch where you live) needs to send no faster than 9600 baud because at anything faster, the PLL loses lock. You must change the baud rate in the ESP8266 sketch to match. From the documentation: "change Line 41 or thereabouts in the ESP8266 file “src.ino”.
I believe the ESP8266 compatible software is here: GitHub - openenergymonitor/EmonESP: ESP8266 WIFI serial to emoncms link
I cannot help you with platformio - when I tried it, it moved files and broke my system, it took half a day to put everything back to how it should be.
I use the Arduino IDE - all the installation instructions for the IDE and the libraries are in the “Learn” section here.