This is sagar, I have to design Loop Powered Transmitter with TWO 4-20mA output current,
1st 4-20mA is used to measure Analog signal 1
2nd 4-20mA is used to measure Analog signal 2
Please help me in design circuit or give me block diagram.
Thank you in advance...!!!
Are the two measurements independent? Current loops support a single transmitter and one or more receivers in. Some transmitters include their own power supply, and a loop-powered transmitter implies that you have a power source elsewhere in the loop.
Circuit Note 0267 is a good example of a loop powered transmitter. It is based on the AD5421, which has a SPI interface and an internal DAC, while an ADuCM360 digitizes the analog input signal and a temperature sensor. This arrangement allows you to perform temperature compensation and digital calibration.
If you are looking for a purely analog solution, the AD693 may be an option, or do a parametric search on ADI's 4-20mA drivers: