Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

How design a isolated current loop 0/4..20mA??

Status
Not open for further replies.
G

gauchosuizo

Junior Member level 3
Joined
Jul 14, 2004
Messages
31
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
Argentina
Activity points
233
isolated current loop

hi guys

I'm looking for a current loop 0/4..20mA. I've a PIC with a PWM output and I want to need this to control the current loop. My idea is the following:
With a Filter (LPF) I can convert the PWM into a DC Voltage and with them I can drive a VCO. The generated Signal from VCO will be connected to a transformator. On the secondary side of this I get a voltage, wich I can rectifier and need as a current output. What do you think about this?

If you have an other Idea, it's welcome. Maybe has anyone a circuit? other a link?

Thank you very much and aloha

Pablo
 

isolated current loop dac

I've seen a lot of application notes from Analog Devices concerning current loops. Just as a option for you to look for.
 

hi Mr_Programmer

thank you for your answer. I will check the homepage from AD.

Aloha Pablo
 

see dac8512 data sheet, there are an example, you can change 8512 with dac
 

hi

I've checked the page from AD and I've found nothing. I don't know where you saw it. Please if you have some link about this, I will be very happy.
You must see: the current loop must be not expensive and as simply as possible.

Thanks

Pablo
 

Pablo,

I'm sorry, I was wrong. I saw app notes in a Burr Brown Application book, but TI bought Burr Brown not AD. Again, I'm sorry.
I make a search at TI web site for "current loop" and got 500+ hits.

Under the first 25 hits is the following:
https://focus.ti.com/lit/an/sboa025/sboa025.pdf

In this app note you can also see the internals of a XTR1xx, I hope this will help you.

Regards...
 

hi Mr_Programmer

I know this application note and the IC line XTR... My problem is, that the current loop must be isolated. Now how can I isolate the current loop? With a transformator or maybe with optocouplers?
You see my problem?

Thanks and regards from Switzerland.

Pablo
 

Hi,

Here are some links :

h**p://www.bb-europe.com/bb-euro/literature/curentlp.pdf

h**p://www.discovercircuits.com/C/cur-loop.htm

* = t
 

@Pablo:
Well ... I see...

I found this circuit, it works with optocouplers:
**broken link removed**

Regards from Germany
 

hi guys

thanks for your answers.
@koky
I've checked the circuit. It's not what I'm looking for, you know? I don't want to need to much components on the isolated side. Therefor I thought at a transformator to isolate the current loop.

@Mr_Programmer
thanks again for your answer. I know this design. First I want to try with a transformator.

@papyaki
Thanks for the links. I will see it.

Regards and aloha

Pablo
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top