Re: scada
SCADA: Supervisory Control And Data Aquisition
Generally used to remotely monitor and control substation equipment such as breakers, switches, and sectionallizers. Usually works on fiber-optic systems tied to Remote Terminal Units (RTU's) at each substation and at the control point (dispatcher).
PLC: Programmable Logic Controller
Programmable controller generally used to control motors and other systems requiring complex logic to start and stop motors, etc. on certain input configurations.
DCS: No Idea.
Hope that helps.