This board is a simple carrier of Allegro’s ±31A ACS711EX Hall effect-based linear current sensor with overcurrent fault output, which offers a low-resistance (~0.6 mΩ) current path and electrical isolation up to 100 V. Measuring up to 31A in either direction this sensor outputs an analog voltage and works with 5V or 3.3V systems.
In stock in Australia
Our Code: SEN-10058
Supplier Link: [Pololu MPN:2453]
This current sensor is a carrier board or breakout board for Allegro’s ACS711KEXLT-31AB-T Hall effect-based linear current sensor with overcurrent fault output; we therefore recommend careful reading of the ACS711 datasheet (551k pdf) before using this product. This sensor has an operating voltage of 3 V to 5.5 V and an output sensitivity of 45 mV/A when Vcc is 3.3 V (or 68 mV/A when Vcc is 5 V). The following list details some of the sensor’s key features:
The pads are labeled on the bottom silkscreen, as shown in the picture to the right. The silkscreen also shows the direction that is interpreted as positive current flow via the +i arrow.
The sensor requires a supply voltage of 3 V to 5.5 V to be connected across the Vcc and GND pads, which are labeled on the bottom silkscreen. The sensor outputs an analog voltage that is linearly proportional to the input current. The quiescent output voltage is Vcc/2 and changes by 45 mV per amp of input current (when Vcc = 3.3 V), with positive current increasing the output voltage and negative current decreasing the output voltage. The relationship between the instantaneous input current, i, and sensor output voltage, VOUT, can be represented by the following equations:
The FAULT pin is normally high and latches low when the current exceeds ±31 A. Once the FAULT pin is latched low, the only way to reset it is by toggling power on the Vcc pin. In our tests, this module was able to handle 31 A of continuous current without exceeding 100°C, with no cooling beyond the heat dissipation of the PCB.
ACS711EX Current Sensor connections
ACS711EX Current Sensor - can attach terminal connectors
The input current can be connected to the board in a variety of ways. Holes with 0.1″, 3.5 mm, and 5 mm spacing are available as shown in the diagram above for connecting male header pins or terminal blocks. For high-current applications, you can solder wires directly to the through-holes that best match your wires, or you can use solderless ring terminal connectors, as shown in the picture above. The large through-holes are big enough for #6 screws.
The board has two mounting holes on the logic side of the board. These mounting holes are 0.5" apart and are designed for #2 scews.
This board ships assembled with all surface mount components, and a 5×1 strip of 0.1″ header pins is included but not soldered in, as shown in the picture below.
ACS711EX Current Sensor Included bits
ACS711EX Current Sensor - Schematic
|Size:||0.7″ x 0.8″|
|Current sense:||0.045 V/A2|
|Minimum logic voltage:||3 V|
|Maximum logic voltage:||5.5 V|
|Supply current:||4 mA|
ACS711 datasheet (489k pdf)