LOW POWER TWO-WIRE SELF VALIDATING TEMPERATURE TRANSMITTER

摘要

A two-wire temperature transmitter (12) is coupleable to a two-wire process control loop for measuring temperature of a process. The transmitter includes an analog to digital converter (20) configured to provide digital output (22) in response to an analog input (24). A two-wire loop communicator (26) is configured to couple to the process control loop (16) and send information on the loop (16). A microprocessor (28) is coupled to the digital output (22) and configured to send temperature related information on the process control loop (16) with the two-wire loop communicator (26). A power supply (30) is configured to completely power the two-wire temperature transmitter (12) with power from the two-wire process control loop. A temperature sensor (34) comprises at least two (16) temperature sensitive elements having element outputs which degrade in accordance (60, 62, 64, 66, 68) with different degradation characteristics. The element outputs are provided to the analog to digital converter (20), such that the microprocessor (28) calculates temperature related information as a function of at least one element output from a first temperature sensitive element (60, 62, 64, 66, 68) and at least as a function of one degradation characteristic of a second temperature sensitive element (60, 62, 64, 66, 68).