Home

Welcome to the pi_ina219 wiki!

#Continuous Integration

See Travis CI: https://travis-ci.org/chrisb2/pi_ina219

#Code Coverage Report

A code coverage report of the unit tests is automatically generated by Travis CI, see https://codecov.io/gh/chrisb2/pi_ina219

#Example of Auto Gain in Operation

The following Python script demonstrates auto gain in operation.

#!/usr/bin/env python

import time
import logging
from ina219 import INA219
from ina219 import DeviceRangeError

SHUNT_OHMS = 0.1


def read():
    ina = INA219(SHUNT_OHMS, log_level=logging.INFO)
    ina.configure()

    while True:
        v = ina.voltage()
        a = 0.0
        w = 0.0
        s = 0.0
        try:
            a = ina.current() / 1000
            w = ina.power() / 1000
            s = ina.shunt_voltage()
        except DeviceRangeError as e:
            print e
            a = 0.0
            w = 0.0
            s = 0.0

        print ("%.2fV, %.3fA, %.3fW, %.3fmV" % (v, a, w, s))
        time.sleep(1)


if __name__ == "__main__":
    read()

As the voltage was increased, the INFO log output, shows the gain starting at 40mV, then increasing to 80mV, 160mV, 320mV and finally exceeding the maximum range of the device. When the voltage is then reduce, valid readings are once again obtained.

2017-03-04 19:40:36,512 - INFO - INA219 gain set to 0.04V 2017-03-04 19:40:36,515 - INFO - INA219 calibrate called with: bus max volts: 32V, max shunt volts: 0.04V 2017-03-04 19:40:36,518 - INFO - INA219 max possible current: 0.400A 2017-03-04 19:40:36,520 - INFO - INA219 current LSB: 1.220e-05 A/bit 2017-03-04 19:40:36,523 - INFO - INA219 power LSB: 2.439e-04 W/bit 2017-03-04 19:40:36,526 - INFO - INA219 max current before overflow: 0.3996A 2017-03-04 19:40:36,528 - INFO - INA219 max shunt voltage before overflow: 39.9598mV 2017-03-04 19:40:36,531 - INFO - INA219 calibration: 0x8333 (33587) 0.00V, 0.027A, 0.000W, 2.700mV 0.00V, 0.027A, 0.000W, 2.710mV 0.00V, 0.028A, 0.000W, 2.800mV 0.00V, 0.032A, 0.000W, 3.210mV 0.00V, 0.034A, 0.000W, 3.460mV 0.01V, 0.040A, 0.000W, 3.980mV 0.11V, 0.239A, 0.026W, 24.290mV 0.18V, 0.384A, 0.071W, 38.380mV 2017-03-04 19:40:47,699 - INFO - INA219 Current overflow detected - attempting to increase gain 2017-03-04 19:40:47,705 - INFO - INA219 gain is currently: 0.04V 2017-03-04 19:40:47,708 - INFO - INA219 calibrate called with: bus max volts: 32V, max shunt volts: 0.08V 2017-03-04 19:40:47,712 - INFO - INA219 max possible current: 0.800A 2017-03-04 19:40:47,715 - INFO - INA219 current LSB: 2.439e-05 A/bit 2017-03-04 19:40:47,719 - INFO - INA219 power LSB: 4.878e-04 W/bit 2017-03-04 19:40:47,721 - INFO - INA219 max current before overflow: 0.7992A 2017-03-04 19:40:47,724 - INFO - INA219 max shunt voltage before overflow: 79.9195mV 2017-03-04 19:40:47,727 - INFO - INA219 calibration: 0x4199 (16793) 2017-03-04 19:40:47,735 - INFO - INA219 gain set to: 0.08V 0.21V, 0.439A, 0.095W, 44.030mV 0.23V, 0.459A, 0.109W, 45.940mV 0.29V, 0.560A, 0.166W, 56.350mV 2017-03-04 19:40:50,790 - INFO - INA219 Current overflow detected - attempting to increase gain 2017-03-04 19:40:50,795 - INFO - INA219 gain is currently: 0.08V 2017-03-04 19:40:50,799 - INFO - INA219 calibrate called with: bus max volts: 32V, max shunt volts: 0.16V 2017-03-04 19:40:50,803 - INFO - INA219 max possible current: 1.600A 2017-03-04 19:40:50,806 - INFO - INA219 current LSB: 4.878e-05 A/bit 2017-03-04 19:40:50,810 - INFO - INA219 power LSB: 9.756e-04 W/bit 2017-03-04 19:40:50,814 - INFO - INA219 max current before overflow: 1.5984A 2017-03-04 19:40:50,817 - INFO - INA219 max shunt voltage before overflow: 159.8390mV 2017-03-04 19:40:50,821 - INFO - INA219 calibration: 0x20cc (8396) 2017-03-04 19:40:50,830 - INFO - INA219 gain set to: 0.16V 0.50V, 0.864A, 0.448W, 86.790mV 0.64V, 0.934A, 0.594W, 93.390mV 0.76V, 1.014A, 0.776W, 101.430mV 0.93V, 1.052A, 0.977W, 105.270mV 0.99V, 1.074A, 1.061W, 107.390mV 1.16V, 1.176A, 1.370W, 117.800mV 1.45V, 1.257A, 1.825W, 125.740mV 1.66V, 1.351A, 2.249W, 135.260mV 1.87V, 1.382A, 2.576W, 138.210mV 2.08V, 1.443A, 3.002W, 144.350mV 2.45V, 1.565A, 3.833W, 156.650mV 2017-03-04 19:41:07,085 - INFO - INA219 Current overflow detected - attempting to increase gain 2017-03-04 19:41:07,090 - INFO - INA219 gain is currently: 0.16V 2017-03-04 19:41:07,094 - INFO - INA219 calibrate called with: bus max volts: 32V, max shunt volts: 0.32V 2017-03-04 19:41:07,098 - INFO - INA219 max possible current: 3.200A 2017-03-04 19:41:07,101 - INFO - INA219 current LSB: 9.756e-05 A/bit 2017-03-04 19:41:07,105 - INFO - INA219 power LSB: 1.951e-03 W/bit 2017-03-04 19:41:07,109 - INFO - INA219 max current before overflow: 3.1968A 2017-03-04 19:41:07,113 - INFO - INA219 max shunt voltage before overflow: 319.6780mV 2017-03-04 19:41:07,117 - INFO - INA219 calibration: 0x1066 (4198) 2017-03-04 19:41:07,126 - INFO - INA219 gain set to: 0.32V 2.70V, 1.625A, 4.398W, 162.430mV 3.07V, 1.713A, 5.253W, 171.410mV 3.66V, 1.892A, 6.944W, 189.360mV 4.20V, 2.018A, 8.494W, 201.850mV 4.64V, 2.105A, 9.754W, 210.580mV 5.28V, 2.266A, 11.977W, 226.570mV 5.83V, 2.374A, 13.846W, 237.460mV 6.32V, 2.480A, 15.688W, 248.150mV 6.92V, 2.604A, 18.053W, 260.710mV 7.76V, 2.761A, 21.442W, 276.190mV 8.21V, 2.844A, 23.360W, 284.530mV 8.92V, 2.971A, 26.519W, 297.240mV 9.15V, 3.009A, 27.532W, 300.980mV 10.02V, 3.159A, 31.666W, 316.070mV 10.27V, 3.197A, 32.835W, 319.540mV 2017-03-04 19:41:32,538 - INFO - INA219 Current overflow detected - attempting to increase gain 2017-03-04 19:41:32,542 - INFO - INA219 gain is currently: 0.32V 2017-03-04 19:41:32,544 - INFO - INA219 Device limit reach, gain cannot be increased Current out of range (overflow), for gain 0.32V, device limit reached 10.28V, 0.000A, 0.000W, 0.000mV 2017-03-04 19:41:33,556 - INFO - INA219 Current overflow detected - attempting to increase gain 2017-03-04 19:41:33,560 - INFO - INA219 gain is currently: 0.32V 2017-03-04 19:41:33,563 - INFO - INA219 Device limit reach, gain cannot be increased Current out of range (overflow), for gain 0.32V, device limit reached 10.30V, 0.000A, 0.000W, 0.000mV 9.12V, 2.979A, 27.167W, 297.880mV 8.56V, 2.892A, 24.751W, 289.190mV 8.20V, 2.819A, 23.100W, 281.850mV 8.04V, 2.797A, 22.503W, 279.720mV 8.04V, 2.798A, 22.523W, 279.850mV 7.70V, 2.727A, 20.991W, 272.620mV 7.52V, 2.697A, 20.285W, 269.750mV 7.47V, 2.690A, 20.100W, 269.010mV 7.47V, 2.690A, 20.105W, 269.120mV