Description

This comprehensive design provides a complete system that measures and processes temperature signals  inputs from 2-wire: 3-wire: and 4-wire resistance temperature detectors (RTDs) and outputs a 4 to 20-mA current-loop signal corresponding to the temperature processed from the RTD inputs. It is intended as a reference design for process measurement applications in factory automation: field transmitters and building automation. With less than 0.17 °C maximum measured error over -200 °C to 850 °C: extremely low loop power consumption 1.4mA  (typical including RTD biasing currents) and IEC61000 pre compliance testing: this design significantly reduces the design time for development of high accuracy temperature transmitter systems. It also addresses system level calibration - both offset and gain that can be implemented to improve ADC and DAC accuracy as well as also includes linear interpolation to address the non-linearity of the RTD element.