What is SCADA RTU (Remote Telemetry Unit)?

What is SCADA RTU (Remote Telemetry Unit)?

An RTU (sometimes referred to as a remote telemetry unit) as the title implies, is a standalone data acquisition and control unit, generally microprocessor based, which monitors and controls equipment at some remote location from the central station. Its primary task is to control and acquire data from process equipment at the remote location and to transfer this data back to a central station. It generally also has the facility for having its configuration and control programs dynamically downloaded from some central station. There is also a facility to be configured locally by some RTU programming unit.

Although traditionally the RTU communicates back to some central station, it is also possible to communicate on a peer-to-peer basis with other RTUs. The RTU can also act as a relay station (sometimes referred to as a store and forward station) to another RTU, which may not be accessible from the central station.

Small sized RTUs generally have less than 10 to 20 analog and digital signals, medium sized RTUs have 100 digital and 30 to 40 analog inputs. RTUs, having a capacity greater than this can be classified as large.

A short discussion follows on the individual hardware components.
Typical RTU hardware modules include:
• Control processor and associated memory
• Analog inputs
• Analog outputs
• Counter inputs
• Digital inputs
• Digital outputs
• Communication interface(s)
• Power supply
• RTU rack and enclosure