The unit of measurement of resistance.

A software interface standard that allows Windows programs to communicate with industrial hardware devices. OPC = OLE for Process Control

A person who is able to operate within the Intelli-Site software. Examples of some of the items an operator may be able to do: configure devices, generate reports, view and acknowledge alarm conditions, manage card holders, assign access rights, and issue badges.

A device on a panel which sends a signal or provides information to the field devices to activate controls. Usually a relay which has dry contacts (not supplying power) only switching power provided to it.