Lem Hais 50-P Current Sensor to work with Arduino

Other Hardware Sensors
1

I’m looking for help to wire and code a LEM Hais 50-P current sensor with my Arduino. I need this sensor so I can log discharge current of a battery.

Another team has used this for there telemetry but I need help as the resources aren’t great.
Sensor Link: https://uk.farnell.com/lem/hais-50-p/current-transducer-50a-pcb/dp/1617433
The sensor outputs a reference voltage(2.5v) and the sensor voltage (0-5v), so I give the sensor it’s 5v and ground and then just connect the sensor voltage to A0 and reference voltage to A1 and convert the 0-1023 bits into the relative current, similar to how a voltage sensor is coded?

2

DresselRacing:
I’m looking for help to wire and code a LEM Hais 50-P current sensor with my Arduino. I need this sensor so I can log discharge current of a battery.

Another team has used this for there telemetry but I need help as the resources aren’t great.
Sensor Link: https://uk.farnell.com/lem/hais-50-p/current-transducer-50a-pcb/dp/1617433
The sensor outputs a reference voltage(2.5v) and the sensor voltage (0-5v), so I give the sensor it’s 5v and ground and then just connect the sensor voltage to A0 and reference voltage to A1 and convert the 0-1023 bits into the relative current, similar to how a voltage sensor is coded?

That is pretty much as I read the specs. However, if you also charge the battery through the sensor, the output voltage will be negative. Could be wrong.

Paul

3

Hi Paul,

Only going to need it for the discharge of the batteries but so I actually need to connect the reference voltage or can I just connect the output voltage to an analog pin on the Arduino?

The other team using this used an op-amp after the signal, why would that have used this?
There schematics and resources Current Input - eChook GPT Documentation

4

DresselRacing:
Hi Paul,

Only going to need it for the discharge of the batteries but so I actually need to connect the reference voltage or can I just connect the output voltage to an analog pin on the Arduino?

The other team using this used an op-amp after the signal, why would that have used this?
There schematics and resources Current Input - eChook GPT Documentation

The op amp would be used because the output is the difference between the voltage produced by the monitoring current and the reference voltage. Could be a vary small value.

Paul

5

Int sensorVoltage = analogRead(A0);

Float voltage = (5*sensorVoltage) / (1023); // Analog to digital to covert to voltage

How would I then convert that voltage into current?

6

That "LEM Hais 50-P" sensor seems to have an unusual "voltage output".
Most hall sensors are ratiometric (ACS712, ACS758), and can be easilly read with Arduino's ratiometric A/D.
Your "voltage output" sensor could however have zero and span instability if you read it directly with an Arduino.

I would try to read this sensor with an A/D with reference voltage (absolute A/D), in differential mode.
An ADS1115 breakout board should do the trick (Adafruit.com, ebay).
Output of the sensor to the first input, and reference voltage of the sensor to the second input.
Power sensor and ADS1115 with 5volt from a 5volt Arduino.
Leave the ADS1115 in default PGA mode, and read the difference between input 1 and 2 (differential).
Zero current should yield a value of about zero.
Current should return a positive or negative value (depending on direction).
Apply a simple multiplication factor to that returned A/D value to show current in Amps.

You could do the same (with lower resolution) with two Arduino inputs.
Read sensor output with A0 and sensor reference with A1.
Subtract the two values, and apply a multiplication factor.
Leo..