Remote Terminal Unit: Working and Applications

Remote Terminal Units or RTUs are electronic devices controlled by microprocessors. The RTUs interface physical world objects to SCADA or DCS by transmitting telemetric data to a master system. The RTUs use messages from master supervisory systems to control objects which are connected.

An RTU monitors the analog and digital parameters, thereby transmitting data to a central monitoring system. The central systems are deployed with software for setting up data input connect streams with data output connection streams. The software also deals with communication programs and installation issues.

Working of an RTU

A remote terminal unit comprises of a complex circuit card which consists of various sections required for custom fitted functions. It may also consist of multiple circuit cards or require processing with communication interfaces and digital input, analog input, relay or digital output and analog output cards.

Applications of RTUs

RTUs are highly versatile. Over the years, they have found usage in multiple domains including oil and natural gas, environmental monitoring systems, air traffic maintenance and power generation.

The RTUs are used for remote monitoring of instruments in:

• Oil and natural gas such as onshore oil wells and offshore platforms
• Pump station networks such as water supply or wastewater collection
• Environmental monitoring of parameters such as air quality, pollution and pollutant emission
• Monitoring of mine sites
• Navigation aids
• Water supply, sewage and reservoir systems
• Power generation transmission networks and equipment
• Outdoor alarm systems

RTUs collect onsite data. This data is then fed to a central location with communication protocols. The processed information is sent back to the RTU via the same communication channels.

Why are RTUs popular within the SCADA systems?

RTUs are very popular within the SCADA system. The principal reason behind this is that the RTUs are very versatile. When combined with SCADA and installed in a plant, the labor costs are reduced significantly, and the plant performance is boosted. RTU systems also help in better management of the factory processes as the information gathered by SCADA systems is sent to a centralized location, so that the personnel does not have to feed information manually.

When used intelligently, the RTU systems are also capable of displaying the trends. The information is shown graphically, through which the developing issues can be discovered quickly, and the management can take corrective measures. RTUs are typical to install initially but become user-friendly over time.

Benefits of using remote terminal units in the SCADA systems

• Designed, manufactured and tested for efficiency
• Reliable and complete solution for both software and hardware requirements
• Facilitation of both advanced and modern turnkey SCADA solutions
• Wider operational range
• Advanced communication features
• Compact
• Economic in nature and intelligent investment for long term plant deployment
• Longer lifetime
• Modbus RTU master and slave communication

RTUs are highly multi-functional. With modern communication protocols and advanced features, they aid the SCADA systems in the industry with efficient functioning and better resource management.


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