An electric high-pressure measuring system using a polarimetric fiber-optic sensor

An electronic microcontroller-based system for high-pressure measurement using a fiber-optic sensor is presented. One of the most distinctive problems in such a system is how to deal with a nonmonotonic (sine-like) input-output characteristic of the sensor. The idea of a multisensor system is discussed, and a three-sensor microcontroller-based on-a-card version of the system is presented. An error analysis, the experimental verification of the measurement algorithm and of the level of errors introduced by the A/D (analog/digital) and D/D (digital/digital) conversions, is also presented. An example (pressure measurements in industrial process control) of the system implementation for the pressure range up to 100 MPa with 0.01-MPa resolution is described. In the example, the accuracy is 0.1% and the sensitivity is 0.01%. The system is very cost effective, easy to implement, and insensitive to environmental perturbations.>