The majority of the on-site analysis are performed with portable instruments. The user generally selects the measurement instrument according to the parameters to be monitored, and the features needed.
The applications of the portable measurement devices are manifold: in wastewater treatment plants and in other process installations control measurements are a routine requirement. The results are subsequently evaluated, also on the basis of their plausibility. For example in the fish industry, a continuous surveillance of the breeding tanks would be very costly, and portable instruments are used to monitor some parameters, e.g. dissolved oxygen. In cases similar to these, where documentation plays a secondary role, simple instruments like the 315i from WTW may be used, which are characterized by their simple operation, and do not offer memory and documentation capabilities.
The 330i line of instruments is an excellent option for all those applications where a sporadic storage and documentation of the measured values is needed without any further processing. These instruments are also a good choice for specific applications, when specialized sensors, e.g. for conductivity, are needed.
Almost needless to say, that there are applications where the electronic documentation of the analytical results is of great help. For example, the measured values of subsurface water shall be transferred to a PC. With a data logger a time controlled series of measurements over a longer period of time may be taken. This data may then be visualized on a PC with the most common software. The instruments of the series 340i offer the necessary interfaces for all these features, and, at the same time, may have one or more sensors connected for the different analytical parameters. These multi-parametric instruments are available for the analysis of water, including waste water, either in a simple setup with a single parameter or in a sophisticated and high performance version with multi-parametric sensors capable to measure simultaneously dissolved oxygen, conductivity, temperature and pH. With these instruments it is easy to perform limnological measurements. The software may be updated via Internet