LEM current transducer does not give any output

[sprooch]

lem current transducer

Hi,

I need help fpr my project.
I am using a current transducer from LEM (HXS 20-NP, datasheet attached) for measuring current.

I have 3 components, and my problem is that all the components did not show any output when I changed the current. So, what I am thinking is that the test circuit I made was wrong.

Anyone know what the connection should be?

the connection I made is attached

 

[dfullmer]

how to connect lem current transducer

Are you sure the input & output direction are correct? It looks like you might have these reversed. Then again I might need more coffee...zzzzzzzz

regards

dfullmer

 

[sprooch]

what does a current transducer do?

mmm...

sorry I drew it the wrong way. The connection here is right (I attached the correct drawing).

when I measured the output voltage, it showed 7.34mV. I increased the current and the output voltage keep increasing...7.35mV, 7.36mV and never stops at one value.

 

[dfullmer]

lem transducer connections

so whats the input voltage and is it DC or AC?

 

[dksingh12]

design of a current transducer

mmm...

sorry I drew it the wrong way. The connection here is right (I attached the correct drawing).

when I measured the output voltage, it showed 7.34mV. I increased the current and the output voltage keep increasing...7.35mV, 7.36mV and never stops at one value.

you are using 20A configuration & which current value you want to measure. also whitch type of current I mean AC or DC

 

[FvM]

lem current sensor voltage output

when I measured the output voltage, it showed 7.34mV

7 mV related to VRef or GND? The latter would mean saturation, output voltage is measured differentially to Vref.

 

[sprooch]

lem has current transducers problem

so whats the input voltage and is it DC or AC?

input voltage: 5V DC

you are using 20A configuration & which current value you want to measure

I want to measure 0 - 15 A

7 mV related to VRef or GND?

Vout to Ground




Is the Vref pin in the component an input or output?
What I understand , the Vref is an input, so I put 2.5V there.
I have doubt on my understanding. Maybe it is an output. What do you think?

 

[dfullmer]

lem current transducer connection

Hi

I think it is an output. But with 5 volts across a 2K resistor you will never hit the current you are looking for. 5/2000 = 2.5 milliamps.

Do I understand you correctly?

dfullmer

 

[FvM]

reading data sheet of current transducers

The datasheet is clear in this respect. Vref is IN/OUT with 200 ohms internal impedance. You can either connect it to a load (> 200 k) or supply it from a low impedance external source, when needed. The permissible voltage range is 2.0 to 2.8 V then. Vout must be near to Vref without sensor current. 7 mV referred to ground is out of range. Can't say why, from a distance.

 

[sprooch]

lem transducer

Hey, guys...

I have solved the problem...
The problem was the connection on my PCB...

1 should be the input (1st pin) and 8 will be the output (last pin)..
I connected them wrong....

my mistake on reading the datasheet picture..

thanks for your help...