
Hello, interested in building a simple analyzer - meter of 230V network parameters - single phase.
The meter is based on the ESP32 module according to the diagram attached, and the whole system is not complicated.
You will need the following parts to build the meter:
1 - ESP32 DEVKIT V1 module with 4 MB memory, as in the attached picture;
2 - current measurement sensor - current transformer for the range of 100A with 1V output or for the range of 25A with 1V output type SCT013, as in the attached picture;
3 - voltage measurement sensor - voltage transformer type TV16, as in the attached picture;
4 - 5k precision potentiometer - 2 pieces, as in the attached picture;
5 - 230VAC / 5V 0.7A power adapter or charger with mini USB plug to power the ESP32 module, as shown in the diagram;
6 - universal mounting plate;
7 - resistors and capacitors as in the diagram;
8 - test leads and tips as in the picture of the whole meter.
It's important to buy a converter
current, please choose the type that has a 1V output
I bought all the elements on a well-known auction site, and the total cost did not exceed PLN 150.
Attached are two versions of the software to be uploaded to ESP32. The difference is that one is for a maximum range of 25A, and the other for 100A, depending on which current transformer we buy.
The meter measures and displays the shifts of sinusoidal voltage and current waveforms relative to each other. Calculates COS fi, and in case of detecting the inductive factor, calculates the capacitance of the capacitor to compensate for it.
In addition, it is possible to calculate the THD factor from the measurement of voltage or current with graphs showing harmonic levels - max 9.
Results and graphs are displayed on the screen of a phone, tablet or laptop.
Connection with the meter via Wi-Fi, and the meter has the IP address 192.168.10.1 - picture attached.
The program can be tested immediately after uploading to the ESP32 module without the need to build the entire meter.
Pictures from subsequent screens and the appearance of the meter are attached.
I do not describe too much, because the construction is simple, which even a novice electronics can handle.
All calculations are contained in software, which was not easy for me, especially with counting and measuring harmonics - I wanted to make it legible and give accurate results.
The screens with the results are refreshed every 5 seconds, and the graphs are plotted using the vector graphics function - SVG.
After building the meter, calibration is performed with precision potentiometers.
I calibrated using 2 kettles of 2000W and a digital meter, which is enough to set the voltage and current range as indicated on the meter.
After calibrating, mark the voltage terminal that will be connected to the neutral conductor and the other terminal that will be connected to the phase conductor.
And after putting the current sensor on the phase wire, put it on so that it is in front of the connected voltage wire on the phase.
Connection of the meter to the 230VAC network in the sketch drawing attached.
And when we make sure that the COS fi measurement is correct, you need to mark with a marker the direction of attaching the current sensor to the cable.
I determined this by disabling all pickupselectricity, and leaving the desktop computer and the meter should show the capacitive power factor, if inductive, I will change the direction of the sensor's fastening.
To be sure, you can do a few tests on other devices, e.g. on the motor, and it should show an inductive power factor. When calibrating with kettles, the power factor should be close to 1.
As the housing of the meter, I used the housing of the laptop power supply.
The meter has the ability to update the software without the need to remove the ESP32 module, you can upload the new soft via WIFI using the browser from the address 192.168.10.1/new when the login window appears, user admin password admin , and then select the correct bin file and wait for the message about successful firmware upload.
The inspiration to design and build the meter and write the program code was this article from a few years ago - link below:
https://majsterkowo.pl/rejestrator-napiecia-pradu-mocy/
I am asking for any comments and suggestions for improvement or changes.
Greetings and I wish you satisfaction with using the analyzer - a meter of 230 V single-phase network parameters.
In conclusion, I propose to calibrate the current measurement using 75% of the range. For 25A, I used two electric sensors, 2000W each, because the measurements will be more reliable.
I think many colleagues will see what is going on in our home electrical networks, which will contribute to reducing electricity costs.
Update - software 10/28/2022
For both versions, a scale has been added - horizontal lines for THD graphs.
Increased number of decimal places for voltage and current.
Update - software 07/11/2022
A configuration window has been added so that you can connect to your home router and send data to the server.
link below
https://www.elektroda.pl/rtvforum/viewtopic.php?p=20261095#20261095
Update - software 24/11/2022
Description and programs to upload firmware to ESP32.
https://www.elektroda.pl/rtvforum/viewtopic.php?p=20300780#20300780
Regards
Futek2
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