Hall effect Current Sensor output

[Speedyindian]

Hello everyone,

I am using an birdectional hall effect current sensor to measure the current in a battery cell. The output of the sensor is connected to an PLC . The sensor ouputs the measured current in the range of 4 -20mA and it can measure a maximum of 25A. i.e  4mA= -25A and 20mA= +25A. The PLC is reading the corrct value as i have checked it. when no current flows through it it shows approximatley 12mA, which  represents 0A. Now my question is, how can i programme in such a way that labview changes the measured value into actual current value in Ampere. i.e when the signal outputs 20mA, i want the labview programme to show as 25A in the front panel. Is this done using scaling and if so, can someone explain how it´s done.

Thanking you

Gokul Gopakumar

[GerdW]

Hi Gokul,

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@Speedyindian wrote:

Now my question is, how can i programme in such a way that labview changes the measured value into actual current value in Ampere. i.e when the signal outputs 20mA, i want the labview programme to show as 25A in the front panel. Is this done using scaling and if so, can someone explain how it´s done.

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So you are asking for some basic math lessons? Really?

You know those XY points:

signal  current
 mA        A
  4      -25
 12        0
 20      +25

And now you are looking for the calculation to convert the 4-20mA signal into the measured current (±25A)?

What about a simple linear equation:

current := (signal - 0.012)/0.008 * 25
or
current := 3125 * signal - 37.5

[Speedyindian]

Hello Gerd,

Thank you for the clarification. Umm is the formula right?, because when im using it i am not getting the right values.

Thanking you

Gokul Gopaumar

[GerdW]

Hi Gokul,

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@Speedyindian wrote:

 Umm is the formula right?, because when im using it i am not getting the right values.

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I get correct values with my formulas!

Remember: your signal is in mA, so you get readings like 0.006 or 0.0195...