elschopi/ti_ina226_micropython

Micropython driver for Texas Instruments INA226 power measuring IC

• 👋 Hi, I’m @elschopi
• 👀 I’m interested in all things electronics, 3D printing, tools and mechanical stuff
• 🌱 Besides working as a electronics professional (production / QA), I offer 3D printing, design and consultation services
• 📫 How to reach me: github, email

ti_ina226_micropython's Issues

Lack of one space in 202 line of "ina226.py" file

Hi,
I've tried to use this great library and have got an error:
File "ina226.py", line 202
IndentationError: unindent doesn't match any outer indent level

When I add a missing space in line 202 it works fine :)

Best regards and thanks for this library :)

Limit to current measurement

Using a 0,1 Ohm shunt resistor and with the same parameters of the excelent example here at GitHub, I found that couldn´t measure more than 800 mA, aprox, although the design was for 3,6 A.

Looking at the Shunt Voltage Register (01h) I found that it reached the 32 bits max at that current. So it can´t read any more current, although it is design for

Perhaps It is according to "Shunt voltage input range" parameter in page 5 of specificationes, that says 81,92 mV max.

The problem is solved reducing de Shunt resistor.

MY CONCLUSION: apart from calculations, take care of the value of Shunt resistor in order to avoid register 01h reach the limit.

Thank you very much for the files adapting the INA219 micropython software to INA 226. It is very useful for me. And I´ve learnt a lot

Bug in def shuntvoltage

I discovered a bug in the library:

@property
    def shunt_voltage(self):
        """The shunt voltage (between V+ and V-) in Volts (so +-.327V)"""    # no, +-80mV!
        value = _to_signed(self._read_register(_REG_SHUNTVOLTAGE))
        # The least signficant bit is 10uV which is 0.00001 volts
        # NO!! It is 2.5uV
        # return value * 0.00001
        return value * 0.0000025

Chris defined the shunt voltage LSB as 10uV, but the datasheet says 2.5uV (page 24)
Unfortunately my results are still wrong after this correction (by a factor 5 for current and power)