emonTx V3 Vrms Bug - Fixed in new V1.2 firmware

We have just discovered a bug in the emonTx V3 firmware which requires CT1 to be connected in order for Vmrs calculation to work. If CT2,3 or 4 is used together the the AC-AC power supply without CT1 being used the Vrms reading will return 0.0V

This bug effects all emonTx V3's shipped before 19th March 2014.

This issue now been fixed, if you like you can download the latest firmware (V1.2) form GitHub and compile and upload via the Arduino IDE, or you can just download the pre-compiled hex and upload via avrdude.



emonTx V3 Firmware Upload Instructions:


Alternatively the issue could be fixed by using CT1 first before any other CT input! If it's required that CT4 (high sensitivity channel) is to be used on it's own just insert a blank 3.5mm jack plug into CT1, it just requires a plug to be there, it does not need to be a CT.