OPTICAL PROCESS VARIABLE TRANSMITTER

摘要

OPTICAL PROCESS VARIABLE TRANSMITTER A light input (26) energizes an optical transmitter (10) providing a light output to a waveguide (16) indicating a process variable. The transmitter (10) has a process variable sensor (21) generating a sensor output. An electrical circuit receives the sensor output and generates an electrical transmitter output indicating the process variable adjusted by a changeable parameter stored in the electrical circuit. The electrical circuit has an input (42,44) energizing the circuit. An LED (58) converts the electrical transmitter output to the light output. A gallium arsenide photodiode (42,44) converts a first portion of received light into electrical energy provided to the energization input (42,44) and converts a second portion of the received light into an electrical output controlling the stored parameter.