Measurements (data) of material streams are the basic source of information of any kind of “information system” for plant or company management.Units (nodes) are connected by material, thermal and mechanical streams. Material streams represent a flow of a mixture of chemical compounds and gathers all properties like density / M.W., temperature, pressure, viscosity, enthalpy, etc.Relate date (measurements) to information by transmission of signals and files, by computing, etc, means to follow a “processus” as defined in the Quality Management. In the data to information” processus each measurements is characterized via its tag (unique name given to a process variable) witch defines the location, type of measurement, accuracy, etc. Each type of measurement, as flow, temperature, pressure, density/M.W., tank dip (level), counters, time, events, etc, is described mainly in term of source of potential errors. Propagation of accuracy (mutual influence of errors) during signal transformation (from analog to digital), data and files calculations principles are explained and errors are evaluated.
Statistical treatment of error’s evolution is examined and error’s trend is compared to correctives actions of maintenance sector. Reliability and Quality of information are defined and explained.