What is SCADA?

  • SCADA is short for Supervisory Control and Data Acquisition.
  • Since about 1998, virtually all major PLC manufacturers have offered integrated HMI/SCADA systems, many of them using open and non-proprietary communications protocols.
  • The HMI industry was essentially born out of a need for a standardized way to monitor and to control multiple remote controllers, PLCs and other control devices.
  • While a PLC does provide automated, pre-programmed control over a process, they are usually distributed across other terrains or remote locations, sometimes making it difficult to gather data from them manually. This in turn, requires the user to make a special trip to the site to either reset the system, or do a daily checkup.
  • An HMI may also be linked to a database, to provide trending, diagnostic data, and management information such as scheduled maintenance procedures, logistic information, detailed schematics for a particular sensor or machine, and expert-system troubleshooting guides.