Supervisory Control and Data Acquisition

Today’s Supervisory Control and Data Acquisition (SCADA) systems incorporate. Programmable Logic Controllers (PLCs), Human Machine Interface (HMI) workstations and network communication systems into a complete integrated system. Each of the major components requires one or more form of programming from program logic to configuration to process graphic displays to communication configuration. Since there are many aspects to the SCADA application software, it is important to use a structured organized approach to the design and development of this software; hence, the establishment of standards is very important.
A SCADA (Supervisory Control and Data Acquisition) is an automation control system that is used in industries such as energy, oil and gas, water, power, and many more. The system has a centralized system that monitors and controls entire sites, ranging from an industrial plant to a complex of plants. Across the country a SCADA system works by operating with signals that communicate via channels to provide the user with remote controls of any equipment in the given system. It also implements a distributed database that contains tags or points throughout the plant. These points represent a single input or output value that is monitored or controlled by the SCADA.

scada system


  • Flexible and open architecture
  • Basic SCADA functionality
  • MMI
  • Alarm Handling and Trending
  • Access Control
  • Automation
  • Logging, Archiving, Report Generation
  • Interfaces to H/W and S/W
  • Development Tools


Alarm Handling

  • Based on limit and status checking
  • More complicated expressions developed by creating derived parameters
  • Alarms are time stamped and logically centralized
  • Notifications (audible, visual, Email, GSM)
  • Multiple alarm priority levels
  • Grouping of alarms and handling of groups is possible
  • Suppression and masking of alarms either individually or as a complete group
  • Filtering of alarms is possible


  • Multiple trending charts
  • Charts are pre-defined or configured on-line
  • Charts contain multiple pens,
  • Zooming, scrolling, panning, ‘Hairline’
  • Real-time and historical trending


  • Users organised in groups with a set of allocated privileges
  • Large number of groups possible
  • Privileges limit write access to process parameters
  • Some allow access to graphics and functionality to be limited


  • Actions can be initiated automatically triggered by an event
  • Recipes
  • Sequencing and scripting possibilities


  • Data stored in compressed and proprietary format
  • Logging / Archiving either for a set number of parameters or for a set period of time
  • Logging / Archiving can be frequency or event driven
  • Logging of user actions together with a user ID
  • VCR facility for playback of stored data


  • Reports created using SQL type queries to the RTDB or logs
  • Automatic generation, printing and archiving of reports
  • Use of ‘components’ for report generation

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