0-10V to 4-20mA
0-10V to 4-20mA
(OP)
Hi, i know this question has been asked many times. I want to achieve the 4-20mA without chips(XTR115/116 etc). I know someone said that you can do that using op-amps but nothing specific was said. Could someone help by giving me specific details. Thank you.





RE: 0-10V to 4-20mA
http://www.analog.com/UploadedFiles/Data_Sheets/390142776AD694_b.pdf
I used an 8-bit port on a PIC to generate 0-255 which I converted to 0-10V that fed the V to I circuit. The output was 0 to 25.5mA.
Hope this helps.
(I did notice that if no load was connected the op-amp got hot! Never did find out why.)
Dave
RE: 0-10V to 4-20mA
RE: 0-10V to 4-20mA
If it works, you should then have a poor version of the AD694!
RE: 0-10V to 4-20mA
http://www.allaboutcircuits.com/vol_3/chpt_8/7.html
xnuke
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: 0-10V to 4-20mA
A higher gain transistor, such as a darlington, and a resistor from op amp to transistor base will solve the problem.