A remote terminal unit (RTU) is a microprocessor-controlled electronic device that interfaces objects in the physical world to a distributed control system or SCADA (supervisory control and data acquisition) system by transmitting telemetry data to a master system, and by using messages from the master supervisory system to control connected objects


Architecture :

An RTU monitors the field digital and analog parameters and transmits data to the Central Monitoring Station.

It contains setup software to connect data input streams to data output streams, define communication protocols, and troubleshoot installation problems.


A RTU may be interfaced to multiple master stations and IEDs (Intelligent Electronic Device) with different communication media (usually serial (RS232, RS485, RS422) or Ethernet).

An RTU may support standard protocols (Modbus, IEC 60870-5-101/103/104, DNP3, IEC 60870-6-ICCP, IEC 61850 etc.) to interface any third party software.

Applications
Remote monitoring of functions and instrumentation for:
Oil and gas (offshore platforms, onshore oil wells)
Networks of pump stations (waste water collection, or for water supply)
Environmental monitoring systems (pollution, air quality, emissions monitoring)
Mine sites
Air traffic equipment such as navigation aids (DVOR, DME, ILS and GP)
Remote monitoring and control of functions and instrumentation for:
Hydro-graphic (water supply, reservoirs, sewage systems)
Electrical power transmission networks and associated equipment
Natural gas networks and associated equipment
Outdoor warning sirens