Problems with Arduino of the INA226 module

Hi Paolo,

You didn’t make it clear what the expected readings are, in contrast to what the system returns.

However, you passed 100mOhm shunt resistor to the calibration routine while you said you had 10mOhm in hardware. This will definitely mess it up.

Regards, Guang

Hi. The code give me a Bus Voltage about plus or minor 0.04V as you can see, but the real Bus Voltage on the LOAD is  about plus or minor 5V!That is the problem. You can read the Serial Monitor that i report to the post before.

About the resistor shunt i said that for the precision that i want i'll replace the R shunt that now is 100mOhm with the 10mOhm that was shipped from China and will arrive to me in 20 days! But the Arduino Code that i post is about the R Shunt that now i have on board (so 0.1 Ohm , 100mOhm).

Hi Paolo,

If Vbus reading is wrong, have you checked with a meter what this voltage really is on the pin #3? I don’t see any connection to it in the schematic, it is shown floating.

Regards, Guang

Are you speak about the pin VBS? What connection i've to do?

Hi Paolo,

I thought it reads “VBus”, ha! What is “VBS” anyways?

You want to measure on INA226 VBUS pin to make sure it shows 5V, that’s where the voltage is measured by the IC.

Regards, Guang

You are right! I'have to connect the VBS before the + LOAD and now it works well and give me this results

Bus voltage: 4.86 V    <---- OK it's right
Bus power: 0.025 W    <---- OK it's right
Shunt voltage: 0.00046 V
Shunt current: 0.0046 A    <---- OK it's right

Now i have also a question....i'd to use 4 module INA226. Each of the modules will have its address depending on the connections I will make between A0, A1, GND, VCC, etc. but my question now is another: how can I assign a name to each variable?

To be clear, let's take the example by putting 2 INA226 modules, one on a 12V network and one on a 5V, for example the first will have address 0X40 and the other 0x41 but both will have in the code

Serial.print (ina.readBusVoltage (), 2);

as well as
  Serial.print (ina.readBusPower (), 3);

is
  Serial.print (ina.readShuntCurrent (), 4);

... How can I get the readings of what will read the 12V voltage and what will read 5v?

Hi Paolo,

You’d have to call on the four INA226 one at a time. The related commands must now all reside in the forever loop.

There are different ways of doing it, what I would do is - push the essential initialization/setup commands including some “.h” variables down to the forever loop. 

It is easy to retrieve the readings as you know which one you’re calling, You can use the same local variables, and transfer to others.

You can probably consolidate these commands into a sub program for better readability. This command can be enclosed inside a “for” loop such that each iteration, you only update the device address (and possibly others such as calibration value as needed) and transfer readings.

This is just a suggestion; I believe you’re able to implement this or some other ways. Whichever you choose, give it a try and I guarantee it will be fun.

Regards, Guang

ok ... but I don't know how to do it ... here below I put the connection scheme of the 4 INA226 modules each with different voltage 12V, 5V, 5V USB and 3.3V.
The aim then is to show all the voltage and current readings of each module on the NEXTION Display (which I divided into 4 parts each for one of the 4 voltages and each letter box of the display must correspond to a variable).
So for example the current read from the INA226 of the 5V should be called Current_5V, that of the INA226 of the 12V should be called Current_12V ... only if I am in the void loop only by code

  Serial.print ("Shunt current:");
  Serial.print (ina.readShuntCurrent (), 4); // value to 3 decimal places
  Serial.println ("A");

then I don't know how to assign them to the different different variable modules ...
I hope I was clear as clear as possible ... do you have any advice?

I tried to throw this scketch down but it doesn't work!

/*
    INA226 Bi-directional Current/Power Monitor. Simple Example.
    Read more: www.jarzebski.pl/.../cyfrowy-czujnik-pradu-mocy-ina226.html
    GIT: github.com/.../Arduino-INA226
    Web: http://www.jarzebski.pl
    (c) 2014 by Korneliusz Jarzebski
*/

#include <Wire.h>
#include <INA226.h>

INA226 ina_5V;
INA226 ina_3.3V(0x45);

void checkConfig()
{

  Serial.print("Max possible current 5V:  ");
  Serial.print(ina_5V.getMaxPossibleCurrent());
  Serial.println(" A");

  Serial.print("Max current 5V:           ");
  Serial.print(ina_5V.getMaxCurrent());
  Serial.println(" A");

  Serial.print("Max shunt voltage 5V:     ");
  Serial.print(ina_5V.getMaxShuntVoltage());
  Serial.println(" V");

  Serial.print("Max power 5V:             ");
  Serial.print(ina_5V.getMaxPower());
  Serial.println(" W");

  Serial.print("Max possible current 3.3V:  ");
  Serial.print(ina_3.3V.getMaxPossibleCurrent());
  Serial.println(" A");

  Serial.print("Max current 3.3V:           ");
  Serial.print(ina_3.3V.getMaxCurrent());
  Serial.println(" A");

  Serial.print("Max shunt voltage 3.3V:     ");
  Serial.print(ina_3.3V.getMaxShuntVoltage());
  Serial.println(" V");

  Serial.print("Max power 3.3V:             ");
  Serial.print(ina_3.3V.getMaxPower());
  Serial.println(" W");

}

void setup() 
{
  Serial.begin(115200);

  Serial.println("Initialize INA226");
  Serial.println("-----------------------------------------------");

  // Default INA226 address is 0x40
  ina_5V.begin();
  ina_3.3V.begin();

  // Configure INA226
  ina_5V.configure(INA226_AVERAGES_1, INA226_BUS_CONV_TIME_1100US, INA226_SHUNT_CONV_TIME_1100US, INA226_MODE_SHUNT_BUS_CONT);
  ina_3.3V.configure(INA226_AVERAGES_1, INA226_BUS_CONV_TIME_1100US, INA226_SHUNT_CONV_TIME_1100US, INA226_MODE_SHUNT_BUS_CONT);


  // Calibrate INA226. Rshunt = 0.1 ohm, Max excepted current = 4A
  ina_5V.calibrate(0.1, 4);
  ina_3.3V.calibrate(0.1, 4);


  // Display configuration
  checkConfig();

  Serial.println("-----------------------------------------------");
}

void loop()
{
  Serial.print("Bus voltage 5V:   ");
  Serial.print(ina_5V.readBusVoltage(), 2); // valore a 2 cifre decimali
  Serial.println(" V");

  Serial.print("Bus power 5V:     ");
  Serial.print(ina_5V.readBusPower(), 3); // valore a 3 cifre decimali
  Serial.println(" W");


  Serial.print("Shunt voltage 5V: ");
  Serial.print(ina_5V.readShuntVoltage(), 5);
  Serial.println(" V");

  Serial.print("Shunt current 5V: ");
  Serial.print(ina_5V.readShuntCurrent(), 4); // valore a 3 cifre decimali
  Serial.println(" A");


  Serial.print("Bus voltage 3.3V:   ");
  Serial.print(ina_3.3V.readBusVoltage(), 2); // valore a 2 cifre decimali
  Serial.println(" V");

  Serial.print("Bus power 3.3V:     ");
  Serial.print(ina_3.3V.readBusPower(), 3); // valore a 3 cifre decimali
  Serial.println(" W");


  Serial.print("Shunt voltage 3.3V: ");
  Serial.print(ina_3.3V.readShuntVoltage(), 5);
  Serial.println(" V");

  Serial.print("Shunt current 3.3V: ");
  Serial.print(ina_3.3V.readShuntCurrent(), 4); // valore a 3 cifre decimali
  Serial.println(" A");



  Serial.println("");
  delay(1000);
}