INA226 Element
The modules often com with 4 connectors and breaks out the 4 signal sensing pins from the chip: VBUS, VIN+, VIN- and GND. This allows to use the module for current measurement using the built-in shunt in the high-side or low-side.
The implementation derives from the “SensorElement” class, see Sensor Element Implementation.
High-Side Shunt
This version of connecting power supply and the consumer is according to the Figure 21 in the datasheet where the GND level is shared with Load, Power supply and the I2C bus.
This is my preferred version of using the INA226.
| Board Connector | INA266 Manual | Power connection | Load Connection |
|---|---|---|---|
| V+ | “VBUS” | Power VCC (0 to 36V) | |
| Current+ | “VIN+” | Power VCC (0 to 36V) | |
| Current- | “VIN-” | Load VCC | |
| V- | “GND” | Power GND | Load GND |
Internally V-, GND and I2C-GND is connected.
Low-Side Shunt
Just to document:
| Board Connector | INA266 Manual | Power connection | Load Connection |
|---|---|---|---|
| V+ | “VBUS” | Power VCC (0 to 36V) | Load VCC |
| Current+ | “VIN+” | Load GND | |
| Current- | “VIN-” | Power GND | |
| V- | “GND” | Power GND |
Internally V-, GND and I2C-GND is connected.
I2C bus connectivity
The I2C Connection is as usual. The VCC must be provided from the ESP8266 board using 3.3V.
In the Device Element the SCL and SDA pins for the I2C bus need to be specified. These also must be connected to the INA226 board.
The board needs +3.3V VCC power and requires some mA only so regulator on the ESP board can provide this.
| ESP board | INA226 board |
|---|---|
| GND | GND |
| 3V3 | VCC |
| D2 | SCL |
| D1 | SDA |