Find Constant of Proportionality for Current Transducer

[boreilly]

Homework Statement

The output voltage of a current transducer is proportional to the the current it is detecting/reading. i need to know the constant of proportionality. apparently I should be able to find this on just on a datasheet.

Homework Equations

Vout= K*I. what is K?

The Attempt at a Solution

on the datasheet i do have the equation:
Vout= Vref +/- 0.625*(Ip/Ipn)
Ip is the current being measured(fine)
Ipn is the nominal rms current(which means?)
and it has Vref too.

how do i get it in the form of an equation that i can put in labview. I can only have two variables, the Vout, and the current being measured.
I would have understood nominal current to be the current that a component can take, but it may not be the actual current drawn by the load. but here the Ipn is +/-20 A while the
Ip has a range of +/-60 A. so do i just have the Ip/Ipn part as Ip/20 for the entire range?

 

[berkeman]

Homework Statement

The output voltage of a current transducer is proportional to the the current it is detecting/reading. i need to know the constant of proportionality. apparently I should be able to find this on just on a datasheet.

Homework Equations

Vout= K*I. what is K?

The Attempt at a Solution

on the datasheet i do have the equation:
Vout= Vref +/- 0.625*(Ip/Ipn)
Ip is the current being measured(fine)
Ipn is the nominal rms current(which means?)
and it has Vref too.

how do i get it in the form of an equation that i can put in labview. I can only have two variables, the Vout, and the current being measured.
I would have understood nominal current to be the current that a component can take, but it may not be the actual current drawn by the load. but here the Ipn is +/-20 A while the
Ip has a range of +/-60 A. so do i just have the Ip/Ipn part as Ip/20 for the entire range?

Can you post a link to the datasheet?

 

[boreilly]

dammit can't believe i forgot that

http://datasheet.octopart.com/HXS-20-NP-LEM-datasheet-120813.pdf

i know i could measure the actual current and voltage on the circuit but apparently I should be able just see if on the datasheet which would be easier

 

[berkeman]

dammit can't believe i forgot that

http://datasheet.octopart.com/HXS-20-NP-LEM-datasheet-120813.pdf

i know i could measure the actual current and voltage on the circuit but apparently I should be able just see if on the datasheet which would be easier

Okay, that helps. Definitely not a great datasheet, but I think I see what is going on now.

The Ipn number is a constant, either 5 or 10 or 20 Amps as a baseline for the measurement. you set Ipn by wiring the high-current path differently -- see the wiring diagrams near the end of the datasheet. Once you've wired the current path for 5 or 10 or 20 Amps, that is the reference current that you use in that equation. And Vref is just 2.5V.

 

[boreilly]

Ok. I can work with that. Some other students in a previous year built the circuit so i just need to establish what they set as the base current. thanks.