Dear Sir,
I have been learning many important error problems related to circuits through the AAC forum which is very helpful. As this is my first post sorry for the mistakes if i make any.

Input: 0 to 5 V
Output: 4-20 mA
Application: different gas analyzer circuits, temperature transmitter circuit

I am searching for the precise voltage to current converter as i have tried very popular circuit for this application. Where in analysis software it is working completely normal, but in practical i can not make it work as output behavior is weird. Here i am using LM741 IC instead of LT1490 due to unavailability of part. I am posting the image of sample circuit please let me help to solve.
If anyone know any other circuit i would appreciate the help.

Thank you in advance for the help.

 

Dear Sir,
I have been learning many important error problems related to circuits through the AAC forum which is very helpful. As this is my first post sorry for the mistakes if i make any.

Input: 0 to 5 V
Output: 4-20 mA
Application: different gas analyzer circuits, temperature transmitter circuit

I am searching for the precise voltage to current converter as i have tried very popular circuit for this application. Where in analysis software it is working completely normal, but in practical i can not make it work as output behavior is weird. Here i am using LM741 IC instead of LT1490 due to unavailability of part. I am posting the image of sample circuit please let me help to solve.
If anyone know any other circuit i would appreciate the help.

Thank you in advance for the help.

The standard method for 20mA devices like this is to Run the 4 to 20mA output through a 240 ohm resistor connected to ground. Then your Microcontroller can sense a range of 240 ohms X 20 mA = 4.8V down to 240 ohms X 4 mA = 0.96 V. It is just Ohm's Law.

As for op amps, forget the number 741 unless you remember that number as, "crappy old op amp that should be replaced with some current model". That op amp is about 45 years old and one of the first popular IC for this purpose but a lot happens in 45 years.

 

Thank you for the answer @GopherT. I will find some advanced op-amp nearby like OPO7.. Will it clear my issue? Will ckt work afterwards?

 

The circuit should work provided the opamps have a common mode input range which includes the 24V rail.

 

Dear Sir,
I have been learning many important error problems related to circuits through the AAC forum which is very helpful. As this is my first post sorry for the mistakes if i make any.

Input: 0 to 5 V
Output: 4-20 mA
Application: different gas analyzer circuits, temperature transmitter circuit

I am searching for the precise voltage to current converter as i have tried very popular circuit for this application. Where in analysis software it is working completely normal, but in practical i can not make it work as output behavior is weird. Here i am using LM741 IC instead of LT1490 due to unavailability of part. I am posting the image of sample circuit please let me help to solve.
If anyone know any other circuit i would appreciate the help.

Thank you in advance for the help.

The circuit is 1-5V, 4-20mA your requirement is 0-5V, 4-20mA

 

For an early battery charger project I used a 4-20mA meter for a display. I used a traditional instrument amplifier arrangement to give me offset and slope adjustment. My project is here somewhere. I can find a link if you want.

 

Sure .

But Is it normal to use just instrumentation amp without any other ckt? I mean.. it have sensable temperature drifts ... Will output fluctuate?

 

Sure .

But Is it normal to use just instrumentation amp without any other ckt? I mean.. it have sensable temperature drifts ... Will output fluctuate?

You'll need more design work than my simple project if you want temperature compensation. Do you have some specifications you can share? It's better to get them out at the get go.

Here are some links to the circuit I used, with other inputs you may find useful.

https://forum.allaboutcircuits.com/threads/industrial-4-20ma.97050/#post-722750
https://forum.allaboutcircuits.com/threads/voltage-resistance-to-4-20ma.89982/#post-652914

 

Dear Sir,
I have been learning many important error problems related to circuits through the AAC forum which is very helpful. As this is my first post sorry for the mistakes if i make any.

Input: 0 to 5 V
Output: 4-20 mA
Application: different gas analyzer circuits, temperature transmitter circuit

I am searching for the precise voltage to current converter as i have tried very popular circuit for this application. Where in analysis software it is working completely normal, but in practical i can not make it work as output behavior is weird. Here i am using LM741 IC instead of LT1490 due to unavailability of part. I am posting the image of sample circuit please let me help to solve.
If anyone know any other circuit i would appreciate the help.

Thank you in advance for the help.

LM741C is an old device using a lot of current look at mcp or Opa series.
Use a xtr15 + opamp it does all for you.
Picbuster

 

Not what you actually asked for but Burr Brown had a full line of ICs dealing with 4-20. Amongst them precisely one 0-5 to 4-20. Costly? Maybe.