Convert 0-10V / 2-10V signal to 0-20ma or 4-20ma

[AANZ]

Hi!

I have a Belimo SGF24 which provides a 0-10V (or selectable 2-10V) output.
http://www.belimo.ch/pdf/e/2_Z_4_e5.pdf

Is there a simple circuit to convert this into a 0-20mA or 4-20mA signal? A circuit diagram will be of great help!

Ta!

 

[dgwill]

Siemens do some interface relays - their codes 3RS17001CD00, 3RS17051FD00, 3RS17051FW00 +others. If you use RS Components then their part no. 418-4843 would do. (page 1-1223) - hope this helps?

 

[AANZ]

Thanks!

 

[seppoalanen]

10V/20mA = 500 Ohm resistor between 20mA input and Belimo.
Test 1'st and measure current!

 

[Lare]

I don't think that resistor works now. There is also input resistance which comes to series with 500 ohm, so eventually current is something else than 4-20mA

 

[seppoalanen]

I don't think that resistor works now. There is also input resistance which comes to series with 500 ohm, so eventually current is something else than 4-20mA

Maybe it works with 513 Ohm resistor for 19.5mA. Rest 0.5mA goes to Belimo when output is 20mA and voltage is 10V?
belimo.jpg

 

[Tom Jenkins]

10V/20mA = 500 Ohm resistor between 20mA input and Belimo.
Test 1'st and measure current!

You've got to be careful with this. Most voltage outputs expect the resistance on the output to be quite high, typically 1,000 Ohm or more, and the current to be quite low. Putting a 500 Ohm resistor may draw more current than the output can handle and fault the output. The resistor trick works well going the other way - getting 4-20 mA to a voltage input, but not backwards.

A lot of companies make signal conditioners to go from voltage to current, and this is how I've always done it. For example:
http://www.automationdirect.com/adc/Shopping/Catalog/Process_Controls/Signal_Conditioners/FC-33

 

[seppoalanen]

You've got to be careful with this. Most voltage outputs expect the resistance on the output to be quite high, typically 1,000 Ohm or more, and the current to be quite low. Putting a 500 Ohm resistor may draw more current than the output can handle and fault the output. The resistor trick works well going the other way - getting 4-20 mA to a voltage input, but not backwards.

A lot of companies make signal conditioners to go from voltage to current, and this is how I've always done it. For example:
http://www.automationdirect.com/adc/Shopping/Catalog/Process_Controls/Signal_Conditioners/FC-33

You are Correct, must be careful!
In my example output is 4-20mA and Belimo input needs 2-10V.
Max resistance is 500 ohm for Simatic Analog Out with 4-20mA signal as in my example, so it works. If max resistance is bigger, analog voltage mast get dividing the resistance as trimmer. Mostly max. resistance depends of analog output unit power voltage.
Same Siemens Analog output unit voltage mode output max load is 1kOhm as You mentioned. But problem is how we can use 4-20mA output signal for 2-10V Voltage input signal. Usually everything is possible, it is only Ohm's law.

 

[frankh]

Interface Module 2...10V Converting Into 0...20mA Or 4...20mA

Hi AANZ,

To make a coversion form 2...10V into 0...20mA or 4...20mA, I would suggest using an interface module, like for example offered by Turck.

A detailed description of this module can be found here: http://pdb.turck.de/media/_en/Anlagen/Datei_EDB/edb_7506323_gbr_en.pdf

and also here: www.turck.com

When you would like to order it consider visiting my website,
and clicking on the link for PLCcenter Industrial Store, you will see it in the third collum of this page: http://www.industrial-automation-hands-on.com/help-an-engineer-out.html

Always take care!

 

[Gil47]

In NZ this company probably has the biggest market share, atleast in the circle I move in they do.

http://www.intech.co.nz/nz.html
Transmitters
LP Series
LPI-D is the one I would use in your case

There are lots of companies that make devices that do the same.