Some Ideas about the Design of Measurement Systems

The quality of the state estimation of a system and, consequently, its dependability are strongly conditioned by the number and the location of the measurements. The availability of a system may be increased if this latter is able to function even in the presence of sensor breakdowns. So, the measurement planning (measurement system design) represent a very important stage. This communication presents a method for assessing the availability of the necessary information for the process control and defining the sensor locations such that the variables required for controlling the process remain always observable even if one or more sensors become defective. Underlying, the connections between several concepts such observability, redundancy, sensor location and reliability are emphasised.