Was trying to work out why I wasnt getting any readings when I had the CT clamp plugged into CT1 on the PCB and using the singleCTWatchdog sketch. The comments say CT1 is analogue 0, CT2 is analogue 3. Looking at the schematic, CT1 is 3, CT2 is 0 and CT3 is 1. When using the sketch, CT1 and CT3 are swapped, so to use CT1 I set CT_INPUT_PIN to 3.
From the look of the drawings on the emonTX page, CT1 is the top, i.e. furthest from the rfm12b module but the PCB is labeled CT1. It therefore looks like the labelling on the PCB is incorrect for both CT1 and CT2.
So, in summary, the 3 CT inputs, starting closest to the RFM12B module are CT3 on ADC3, CT2 on ADC0, CT1 on ADC1 which matches the schematic and checked with a meter, but dont match not the drawings.
Is this correct?
I've looked intto it, the problem was the comment in the code was incorrect (it's been corrected now). The port referance table on the emonTx referance page is correct and the PCB silkscreen is correct.
The CT channel ADC port mapping are a bit non sequential due to the way the emonTx evolved (first version only had two CT channels).
The Single CT watchdog sketch uses CT 2 (middle) stocket as the default, this is stated in the comments at the top of the sketch. We have been using this one as default as it's aesthetically pleasing to have the plug half way along one edge of the case. Since we're not supplying cases in the kit maybe this is a bit confusing.
The correct port maps are:
CT 1 - ADC 3 (bottom socket)
CT 2 - ADC 0 (middle socket) - default for Single CT sketch
CT 3 - ADC 1 (top socket)
The drawing at http://openenergymonitor.org/emon/emontx doesnt match, but then I guess this is more a representation than an actual accurate layout.
Well spotted. Yeah, that diagram was drawn before the emonTx design was finished. It's just a representation, although it would be good if it was correct.
Open-source tools for energy monitoring and analysis. This project uses the GNU General Public Licence