Current sensor for Revpi

lujakob · Post by **lujakob** » 23 Jul 2020, 14:10

Hello,

I need a current sensor which will measure a direct current in the range of 0 to 2 Ampere.
I have an analog input module for my Revolution Pi, which I would like to use to connect this sensor.
Does anyone have experience with a suitable sensor which can be connected to the analog module of the Revolution pi?

Many thanks for the help:)
Regards
Ludwig

Post by **dirk** » 24 Jul 2020, 10:26

Hello Ludwig, I can remember using a so called Rogowski Coil. Have a look here at this product which is able to measuere up to 10A.
Also have a look at the Data Sheet of the AIO module.

RR4711 · Post by **RR4711** » 24 Jul 2020, 11:46

dirk wrote: ↑24 Jul 2020, 10:26 Hello Ludwig, I can remember using a so called Rogowski Coil. Have a look here at this product which is able to measuere up to 10A.
Also have a look at the Data Sheet of the AIO module.

@dirk: He wants to measure DC. Those coils only work with AC AFAIK. There is hall sensors-based ones available for example from LEM company. They work quite well, but need seperate supply of 5V for operation (some others +/-15V).
Like this one: https://www.distrelec.de/de/stromwandle ... p/17696305
Depending on how many turns you feed through the core it gets more or less sensitive.

@ludwig: If you don't need galvanic isolation you may actually use a simple shunt resistor to measure the voltage drop across it. ("limits apply", common mode voltage etc, depends on your application, would need more information about it)

lujakob · Post by **lujakob** » 24 Jul 2020, 15:19

Hey Dirk and RR4711,

many thanks for your replies.
I already have the sensor that Dirk is recommending and had no success because of it is measuring just AC.

RR4711, your sensor looks quite good and I gonna have a deeper look on it.
I gonna tell you then if I ordered this one and if I had success with it.

Best regards
Ludwig

Post by **dirk** » 28 Jul 2020, 15:33

Hi Ludwig, thank you for your positive response and thank you RR4711 for your useful hints.

lujakob · Post by **lujakob** » 06 Aug 2020, 18:24

Hey,

I ordered now the LEM Current Transducer LTS-6 NP.
Already tried to implement it but so far, I was not successful.
I always receive a value about 2500.
But I am not confident with how I wired the sensor to the Revolution Pi.
Would you please have a look on the circuit diagram I attached to this reply?

I am very thankful for your help:).
Please ask me if I should provide more information on it.

Best regards
Ludwig

RR4711 · Post by **RR4711** » 06 Aug 2020, 18:28

2500 is fine. The Sensor has it's zero at half the supply voltage (=2,5V), to allow for measuring positive or negative current. If you wrap a wire 3 times though the hole in the center and send the 2Amps current through it, you should measure either 2500-625 or 2500+625 depending on the current direction.

Markus

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