REX, A Computer Controlled Robot for In Situ Water Quality Monitoring

A new, computer oriented system for automatic in situ monitoring of water quality is proposed which makes full and effective use of modern computer technology. A concept for in situ computer controlled experimenting is developed as a reasonable and effective means of automatically observing the wide range of acquatic parameters needed.

The established capability in the teleprocessing industry is assumed as starting point and an optimal design is sought for a sensing head which would meet current expression of requirements for automated water quality monitors while exploiting the advantages of both hardware and software in a total system context. A working model of such a sensing head was constructed and operationally tested using an EAI 690 hybrid computer to simulate the central computer and telecommunications facility. This sensing head consisted of a peristaltic pump, a servo positioned valve, an array of six electrodes (2 glass pH, 3 silver-silver chloride, and 1 gold micro-electrode) and a thermistor, along with buffer amplifiers and motor controllers to service these devices. A main feature is its design as a remote, computer periferal, like a teletype, which understands up to 64 different commands and which returns coded responses. A second feature is its in situ design making the entire sensor head submersible and operable in depths to 100 m.

A repertoire of programmed experiments was developed for the working model system to show how, for example, it could monitor the water quality parameters; temperature, pH, conductivity, dissolved oxygen, chloride ion, total carbon dioxide, total alkalinity, and a factor called “other ions.”