# SPT-0375-600 emonlib.h

what is the possibility of using SPT-0375-600 with the libraries emonlib.h. Will you need to change software or hardware?

Provided that you use the correct calibration constant for your hardware (and you should probably use an ADC input range to 0 - 1 V or slightly more, as that’s the peak-peak swing of the v.t output with a little headroom, for best resolution), then there should be no problem.

But as you don’t say what your hardware is, all that is a guess.

In fact, you will measure the 380v phase on the electrical panel. Here in my country, we have the 220v and 380 phase and I am implementing a protection framework. You will use 6 sennsores. Three for current (sct-013) and three for voltage. I would like to use the sensors here on the website, but it doesn’t seem to measure 380.
The voltage of my ADC is 5v. You can use the same load resistor and voltage dividers proposed here on the website.
I’m using the arduino uno.

No, I will measure 240 V. It might help - it will help quite a lot - if you don’t assume things and to begin, say what your country is. I’m in the UK, and our nominal voltage for homes and small businesses is 240 V. I’ve been the engineer on projects where the incoming supply is 11 kV.

I do not know very much about the Arduino Uno. I believe you can use the internal 1.1 V reference as the reference to the ADC, in which case you must bias the inputs to 0.55 V d.c. If you use the same input circuit as shown in the ‘Learn’ section here, that means you must recalculate the resistor values to give you that voltage.

All the analogue inputs will use the same reference, therefore you must design the current inputs for a burden voltage of 0.333 V at maximum current, and bias those to 0.55 V also.

My parents is Brazil. And here we have different types of pensions between regions that can vary: phase 220 or 380 and neutral phase 220 or 110. So it’s not uniform. I am using or arduino because I am using it as libraries. And I believe that the basic configuration in the libraries is the 5V ADC. If I am programmed in ATMEL STUDIO, set the recorders to 1.1 volts. Try to create a library at ATMEL, but I am facing difficulties. We need help with a hardware configuration. The current reading is already functional. Now the reading of the three voltages is missing. The project is to monitor electric motors up to 20 hp.

To use the 1.1 V internal reference voltage, you can use the circuit in ‘Learn’ for the voltage inputs, but you must change the resistors. You should use R3 = 82 kΩ & R4 = 10 kΩ. Do not use R1 and R2 = 0.

For the current transformers, you can use this circuit in ‘Learn’ , but you must change the resistors. You should use R1 = 82 kΩ & R2 = 10 kΩ.

In the software, you will need to use the 1.1 V internal reference for the ADC. The details are in Section 23.5.2 of the Atmel ATMega328P data sheet: ADC Voltage Reference, and the register you must change is in section 23.9.1: ADMUX – ADC Multiplexer Selection Register.

If you do not use the 1.1 V reference and instead use the Arduino’s normal 5 V reference, then you cannot expect good accuracy from the voltage measurements, because you will use only 20% of the available input range.

Your current transformers will also be more accurate if they only need to generate a voltage of 0.333 V.