Remote Terminal Unit (RTU)'s Status and Role in SCADA

As an important device in the SCADA system—remote terminal unit (RTU) is a durable field intelligent processor responsible for field signal, industrial equipment monitoring, and control. Compared with commonly used PLCs, remote terminal unit (RTU) generally has excellent communication capabilities and greater storage capacity, suitable for harsher temperature and humidity environments. It is precisely due to the RTU's comprehensive functions that RTU products are widely used in SCADA. Below we will provide a more in-depth description of the status and role of RTU in SCADA.

The Status of Remote Terminal Unit in SCADA

Remote Terminal Unit (RTU) is the core device constituting the enterprise comprehensive automation system, typically consisting of signal input/output modules, microprocessors, wired/wireless communication equipment, power supply, and casing, all controlled by a microprocessor and supporting network systems. Through its own software (or intelligent software) system, it ideally realizes the enterprise central monitoring and dispatch system's functions like telemetry, remote control, remote signaling, and remote adjustment of the primary instruments at the production site.

Remote terminal unit (RTU) is a durable field intelligent processor that supports communication between the SCADA control center and field devices. It is an independent data acquisition and control unit. Its role is to remotely control field devices, obtain device data, and transmit the data to the SCADA system's dispatch center.

The Function of RTU in SCADA System

In any SCADA of an application object, remote terminal unit (RTU) can control the scanning of system inputs, typically at a very high speed. It can also process some of the control object's control processes, such as changing the process state, storing data awaiting SCADA monitoring center queries. Some RTUs can even actively report to the SCADA monitoring center. However, in most cases, the SCADA monitoring center selects the RTU. Most RTUs have alarm functions. When an remote terminal unit (RTU) is selected by the SCADA monitoring center, it needs to respond to requirements like "upload all data" to complete a control function. Its main functions are demonstrated as follows:

The monitoring center uses remote addresses for secure data transmission, abnormal data change reports, and efficient communication with multiple remote ends through a single medium.
Remote terminal unit in SCADA can monitor and calculate accumulated pulses obtained from kWh meters.
Remote terminal unit in SCADA can detect, store, and quickly report sudden state changes at a certain state point.
It monitors the analog input and reports to the monitoring center when changes exceed a pre-specified ratio.
In the programmable execution process, it performs execution control on each base point under a select-verify-execute safety mode.
Analog setpoint control.
Remote terminal unit in SCADA can mark an event sequence of state changes with 1ms precision.
Remote terminal unit in SCADA can execute programmable, isolated automatic control algorithms.
Remote terminal unit in SCADA can imitate protocols in byte and bit units.