A power measuring technique for built-in testing of Electrochemical Sensors for Environmental Monitoring

A built-in configuration for monitoring the good operating condition in real-time of an instrumentation system that includes electrochemical sensors is presented in this work. These sensors (mainly dissolve oxygen and pH sensors for online monitoring of water) are widely used in environmental monitoring instruments. The approach is based on a current monitoring circuit which records the changes in the power supply current of such a sensor without practically interfering with its operation and sums this current within a specific time period. The comparison of the resulting power consumption measurement with already known values may indicate the good operating condition of these sensors. The proposed technique is mostly suitable for stand-alone monitoring systems (such as data-loggers or remote stations) which operate continuously in the field of environmental monitoring of water ecosystems (online monitoring). This work uses a microcontroller measuring scheme for implementing the above functionalities.