OpenEnergyMonitor Community

SCT-013-015 (Voltage Output) ESP32 strange Readings?

Hello, i’m just getting started with this. I’m using a ESP32 to firstly calibrate my SCT. As my one has an internal burden (62ohms) i only needed to add 2 10k and one 10uf cap. When i put the clamp on a device consuming 30 watts i get irms1=0.24 when i turn the light off its 0.10. My ICAL is set to (double ICAL = 1.08;) When i put it to one of my mains and start my water kettle i get readings about 24.00. Do i just have to adjust ical?

i’m using 3.3v and GPIO35 on Wemos ESP32.
CT Turns 1800
Burden Resistor 62
Voltage 230v
double I_RATIO = (long double)CT_TURNS / CT_BURDEN_RESISTOR * 3.3 / 4096 * ICAL;

If you’re using emonLib, the calibration is the primary current that gives 1.0 V at the ADC input. So in your case, it should be 15. This assumes that emonLib is picking up the correct number for the ADC resolution - in your case with a 12-bit ADC, ADC_COUNTS (in emonlib.cpp) needs to be 4096. ADC_COUNTS should be supplied by one of the Arduino libraries.

Even for a CT rated at 15 Amps, your test load should be much larger than 30 Watts.
See the Frequently Asked Questions for more info.

I now have a device consuming 240 watts on the clamp, with an ical of 30 it shows readings of 60-62. (i will find an better load later…) Do i still have to set ical higher? or is something with my schematic wrong ? i followed all instructions and left the burden away as mine got an internal burden. I only used the schematic with 2x 10k resistors and one 16v 10uf capacitor. Is is normal that the readings are so low when ical is already set to 30?
by the way my power is running on 50hz

In my calibration code (which is an code from another site) i dont use emonlib, should i use it?

If you use something from another site, and you do not tell us what that is, then you must go back to the other site to ask what is wrong. If you use something that those of us here know about, like emonLib, then we can help you.

Am i Able to use emonlib on esp32 ? if yes i will do for sure… sorry im very new to measuring current with an esp8266/esp32.

i already uploaded EmonESP to my esp8266 but i did not see any possibility to get readings of A0 :frowning:

It appears that there are Arduino libraries for use with the ESP32, and there are at least two analogue inputs (A2 & A3) that will be available always. If these are readable with the normal Arduino analogRead(inPin) function, then it should be possible to use emonLib.

I do not have an ESP32, so I cannot experiment for you, so I cannot say for certain that this is possible.

2 posts were split to a new topic: Interfacing the CT CR8450 with Arduino