crycode-de
ina226
Node.js module to read values from the INA226 bi-directional current and power monitor.
For more information about the INA226 please consult the data sheet from Texas Instruments.
Features
- Read shunt and bus voltages.
- Calculate current and power.
- Read the value from a register.
- Write a value to a register.
Installation
Make sure you are using Node.js v8.x or higher. Current Node.js version is recommended.
npm install ina226This module is written in TypeScript and typings are included.
Example
Note that you need to construct the i2c-bus object and pass it in to the INA226 class.
The example blow can be found in the examples directory of this package together with a TypeScript example.
// Require the ina226 module
const {
CONFIG_AVERAGING,
CONFIG_CONVERSION_TIME,
CONFIG_MODE,
CONFIGURATION_REGISTER,
INA226,
} = require('../'); // = require('ina226');
// Require the i2c-bus module and open the bus
const i2cBus = require('i2c-bus').openSync(1);
// Define the address of the INA226 and the shunt resistance value
const addr = 0x40;
const rShunt = 0.1;
/**
* Main function to demonstrate the INA226 usage in an async context.
*/
async function main () {
// Init a new INA226
const ina = new INA226(i2cBus, addr, rShunt);
// Write to the Configuration Register (0x4527 in this example)
const configValue =
(0b0100 << 12) // Bits 15 - 12, Reset 0 and rest is unused constant
| (CONFIG_AVERAGING.AVG16 << 9) // Bits 11 - 9, Averaging
| (CONFIG_CONVERSION_TIME.CT_1_1ms << 6) // Bits 8 - 6, Bus Voltage Conversion Time
| (CONFIG_CONVERSION_TIME.CT_1_1ms << 3) // Bits 5 - 3, Shunt Voltage Conversion Time
| (CONFIG_MODE.SHUNT_AND_BUS_VOLTAGE_CONTINUOUS << 0); // Bits 2 - 0, Operating Mode
await ina.writeRegister(CONFIGURATION_REGISTER, configValue);
console.log('Configuration written');
// Read the actual bus voltage
const busVoltage = await ina.readBusVoltage();
console.log(`Bus Voltage: ${busVoltage.toFixed(2)}V`);
// Read the actual shunt voltage
const shuntVoltage = await ina.readShuntVoltage();
console.log(`Shunt Voltage: ${shuntVoltage.toFixed(5)}V`);
// Read the actual shunt voltage and calculate the current
await ina.readShuntVoltage();
const current = ina.calcCurrent();
console.log(`Current: ${current.toFixed(2)}A`);
// Read the actual shunt and bus voltages and calculate the power
await ina.readShuntVoltage();
await ina.readBusVoltage();
const power = ina.calcPower();
console.log(`Power: ${power.toFixed(2)}W`);
}
// Call the main function
void main();API
new INA226(i2cBus, address, rShunt)
constructor(i2cBus:I2cBus, address:number, rShunt:number=0.1)Constructor for a new INA226 instance.
i2cBus- Instance of an opened i2c-bus.address- The address of the INA226 IC.rShunt- The shunt resistance value. Defaults to 0.1 Ohm.
Note that you need to construct the i2c-bus object and pass it in to the module.
writeRegister(register, value)
writeRegister(register:number, value:number): Promise<{}>Writes a value to a specific register. Returns a Promise which will be resolves if the value is written, or rejected in case of an error.
register- The register address.value- The value. Should be 16bit integer.
readRegister(register)
readRegister(register:number): Promise<number>Reads a value from a specific register. Returns a Promise which will be resolved with the read value, or rejected in case of an error.
register- The register address.
readBusVoltage()
readBusVoltage(): Promise<number>Reads the actual bus voltage. Returns a Promise which will be resolved with the bus voltage, or rejected in case of an error.
readShuntVoltage()
readShuntVoltage(): Promise<number>Reads the actual shunt voltage. Returns a Promise which will be resolved with the shunt voltage, or rejected in case of an error.
calcCurrent(shuntVoltage)
calcCurrent(shuntVoltage?:number): numberCalculates the current in Ampere based on the shunt voltage an the shunt resistance value.
shuntVoltage- Optional. The shunt voltage which is used for the calculation. Defaults to the last read shunt voltage.
calcPower(busVoltage, shuntVoltage)
calcPower(busVoltage?:number, shuntVoltage?:number): numberCalculates the power in Watt based on the bus voltage, the shunt voltage and the shunt resistance value.
busVoltage- Optional. The bus voltage which is used for the calculation. Defaults to the last read bus voltage.shuntVoltage- Optional. The shunt voltage which is used for the calculation. Defaults to the last read shunt voltage.
Exported constants
The register addresses are exported as constants.
| Constant | Value |
|---|---|
| CONFIGURATION_REGISTER | 0x00 |
| SHUNT_VOLTAGE_REGISTER | 0x01 |
| BUS_VOLTAGE_REGISTER | 0x02 |
| POWER_REGISTER | 0x03 |
| CURRENT_REGISTER | 0x04 |
| CALIBRATION_REGISTER | 0x05 |
| MASK_ENABLE_REGISTER | 0x06 |
| ALERT_LIMIT_REGISTER | 0x07 |
| MANUFACTOR_ID_REGISTER | 0xFE |
| DIE_ID_REGISTER | 0xFF |
Also the enums CONFIG_AVERAGING, CONFIG_CONVERSION_TIME and CONFIG_MODE are exported to allow easier calculations of the configuration register value. See the examples for details on how to use them.
License
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
Copyright (c) 2017-2025 Peter Müller peter@crycode.de https://crycode.de/