24V input to 24Voutput with 4-20mA

[harrisonic]

hello everyone!!

I just need a help on how can i make a 24 volts input source to 24 volts output with 4-20mA output.
..
..do I need to use a current loop primer?..
..unfortunately I'm not familiar with this..

I am gladly appreciate if someone can provide me a diagram..

thank you for the help..and more power.

 

[JimB]

I have no idea what a "current loop primer" is.
I could take a guess, but I have never heared the expression before.

What you need is a constant current generator of some sort.

Have a look at the attachment, just using two components, an LM317 voltage regulator and a variable resistor, you can make a nice little constant current generator.
To calculate the required resistance:

resistance = 1.25/current

Note that the output voltage will not be fixed at 24v, but will vary depending on the load resistance and the current flowing.

Does that help?

Jimb

 

[dr pepper]

I think the o/p wants something that will generate a 4-20ma signal such as used in industrial instrumentation.
You can do it with an op-amp, a volatge to current source circuit, with an offset input to set the zero at 4mA.

Heres an interesting link, with a test circuit for 4-20ma.

**broken link removed**

 

[atferrari]

Heres an interesting link, with a test circuit for 4-20ma.

**broken link removed**

Long time I do not run across of such a clear explanation. Good.

 

[harrisonic]

tnx for all the help..now i know what to do...^_^