TABLE OF CONTENTS The plant engineer needs to know the circumstances under which the plant for which he is responsible is operating. Hence he needs to be able to measure the inputs to the plant and the power inputs to the individual sectors. It will also be necessary to measure the plant outputs. In most cases the instrumentation uses electrical or electronic techniques, i.e. it measures either electrical quantities per se or quantities such as temperature or pressure which have been converted to electrical signals by means of transducers. The degree of accuracy to which these measurements are required will vary, depending on their purpose. In the case where the measurement is used as a direct basis for charging for energy then the accuracy must be very high. This is also the case where precise process control is involved. In other instances it is sufficient for the plant engineer to have a less accurate measurement of what is going on. As well as being technically suitable for the purpose, the instrument chosen will reflect these considerations. In the case of process control the instrumentation must be reliable and it must yield information, often over very long periods of time, which represents the state of the plant or the process and its past history. It is on the basis of this information that the plant engineer will make decisions, many of which will...
