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SCADA is the acronym for Supervisory Control and Data Acquisition. It generally refers to a system that uses a centralized computer to monitor and control data acquired from various locations. SCADA is used in Water/Wastewater Management, Power Transmission and Distribution, Industrial Process Management, Communication Systems, and other systems and industries. With our wide range of experience, UIS PROGRAMMABLE SERVICES, INC. can design a SCADA system to meet your specific needs.
The main components of a SCADA system are:
Most SCADA system functions are performed automatically by the Remote Terminal Units (RTUs). The RTU usually is a Programmable Logic Controller (PLC) that can locally monitor and control different conditions at the remote site. However, human intervention can be allowed and changes can be automatically logged and/or displayed. For example, the RTU may control the operation of a pump to fill a water tank. The set points to start and stop the pump are monitored by the SCADA system to function optimally. However, these set points can be changed or overridden at any time by human intervention.
The SCADA system monitors the entire system in real time. Data acquisition is handled locally at each site by sensors and electromechanical devices that are hard-wired to the RTU. Not only is data processed by the local RTU, but data is also compiled and formatted so that a control room operator using an HMI can monitor or adjust settings. Data is usually recorded and logged for analysis.
The SCADA database system is comprised of elements called tags or points. Each point represents a single value monitored or controlled by the system. A hard point is an actual input or output, while a soft point is the result of an application or software calculation. Points are usually stored as value-timestamp pairs (a value recorded at a particular time) to create a history and to allow trending and other analytical reporting. For example, pump operation and efficiency can be determined with reporting of the number of pump starts and run-time.
The benefits of a SCADA system are numerous. It can be used in small applications as well as large. Here are some of the advantages:
- Real-time information on field conditions
- Faster indication of field problems and faster response to correct
- Higher reliability
- Lower maintenance costs
- Optimal operation of equipment
- Less field travel and more efficient use of employees
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