Supervisory control and data acquisition (SCADA) technology has evolved over the past 30 years as a method of monitoring and controlling large processes. This reference book offers overviews of SCADA's component technologies@ as well as details necessary to understand the big picture. SCADA processes cover areas that may be in the thousands of square miles@ and have dimensions that may be hundreds@ occasionally thousands@ of miles long. Now a mature technology@ SCADA includes@ but is not limited to@ software packages that can be incorporated into a system of hardware and software to improve the safety and efficiency of the operation of these large processes. After completing these 15 self-study units@ readers should be conversant with SCADA nomenclature and architecture@ understand the basic technology of the system's building blocks@ understand its limitations@ understand how it can benefit particular operations@ and have a basis for selecting appropriate SCADA technology for their operational requirements.This Fourth Edition includes a unit about improving the security of SCADA systems and has been rearranged to provide a more logical presentation of the subject.