OPC - OLE (Object Linking and Embedding) for Process Control :: The Industrial Interoperability Standard
Automation, Control & Plant Intelligence - Articles, Analysis, Reviews, Interviews & Views
Almost all HMI/SCADA provides process information for engineers, supervisors, operators and plant managers in the form of reports, displays, archived data, alarms, messages, and statistical charts. The sources of this information are OPC servers or process hardware like controllers, sensors, motors, switches, and other devices which required to manufacture your products.
Normally industrial database (DB) reads process information from these devices and saves it in one or more process databases residing on your SCADA servers.
DB plays an integral part in your Industrial Automation and it is the primary source of process data for most SCADA applications.
Basic concept is same as general databases like MS SQL Server, Oracle etc. but much faster as Industrail Operator Interface required to show live data (some time in milli seconds).