4-20ma sensor

Hi,
What is 4-20ma sensor input,how this can be connected to the microcontroller and how we can generate 4-20ma from microcntroller.

Thank U

which microcontroller you are working on?
and.. i think you misinterpreted "4-20ma"
it might be 4 to 20mA (current) signal.. from sensor circuit. i hope i am right..
this is actually the current sustaining capability of microcontrollers..

(PART A)
you can get 4-20mA current signal by amplifying sensor current/voltage through an OP-Amp (say if you are using photo diode as line or object sensor you need to amplify signals ) so that MCU can get sustaing current as Ajay said
(Part B)
actually you need to amplify current coming out od a MCU therre are several methods to do that like using Transistor as amplifier or ULN2003/2803 (u can amplify upto 500mA per Channel)

Hi,
I think i confused u only by saying 4-20ma . I want to get 4ma o/p from microntroller when the temp of sensor is 0C and 20ma o/p when temp of sensor is 200 C.
See the data sheet attached.

must say.. this kind of sensor is tough... unless worked on it.. :-s