lalitbshah

want to design 4-20mA Loop Powered Indicator. The Indicator will draw the power from the current loop and use less than 3 mA. I want to display the parameter on 3 1/2 LCD or LED. The device is to be made programable with 10 bit ADC. So the it can become general purpose Indicator with the programmable value of 4mA and 20 mA . e.g. i want to use this instrement in 2 wire pressure transmitter and want to display 0000 at 4 mA and 100.0 bar at 20mA. So the instruement will consist of microcontroller (say PIC ) with inbuit ADC and using low current, 4 key for programming and main the Power supply unit which will be grenerated from the 4-20mA loop current. So please help me in designing the powersupply and available ICs for the same design