INTRODUCTION

This chapter does not attempt more than a cursory review of modern control systems, as it is outside my main area of expertise. Those knowledgeable in electronics and control will pass quickly over this chapter! Others who wish to delve more deeply may, for instance, turn to Sanderson (1988), Brignell and White (1994), or other experts, or for a good, recent introduction to the control of machinery Foster (1998) is recommended. I am pleased to acknowledge valuable insights obtained from Cranfield lectures given by Bill Black, David Clitherow, Doug de Sa, and others.

This book is about flowmeters that depend, in the main, on mechanical or thermo/fluid mechanical effects. In only one case of mainstream meters, the electromagnetic meter is the signal electrical throughout. The aim of the book has been to bring together information on the performance of these meters based on physical, experimental, and industrial experience. I have made the assumption that the electrical signal interpretation, which is based in the meter, is capable of doing the job set by the designer of interpreting the meter output into a standard electrical form. This assumption is not always adequate (e.g., where electrical signals from the same instrument do not appear to agree with each other). Nevertheless, the developments in design of electrical systems are assumed to be such that the reader will not benefit from a detailed description or that the circuit will be changing so fast that any statement will be out of date.