What SCADA is and why you need it

SCADA is a software suite that collects data from equipment, presents it to the operator and lets you control processes in real time. The acronym stands for Supervisory Control and Data Acquisition. While a controller (PLC) manages specific equipment on site, SCADA is the «top floor» of automation, from which you can see the entire facility as a whole.

In this article, Atlas Scada engineers explain in plain terms what SCADA is, what it consists of, how it relates to PLCs and I&C instruments, and what tasks it solves on real-world facilities.

Why you need SCADA

Picture a boiler house, a pumping station or the ventilation of a large building. Dozens of sensors measure temperature, pressure and flow; pumps, valves and drives are controlled by controllers. Without supervisory control, the operator would have to walk around the equipment manually and read the values on the spot. SCADA brings all of this onto a single screen: the operator sees the state of the facility, parameter trends and alarms, and can intervene without leaving the control room. That means faster response, fewer mistakes and less time spent on routine rounds.

What a SCADA system consists of

• Field level — sensors and actuators (I&C): they measure parameters and carry out commands.
• Control level — programmable logic controllers (PLCs): they implement the logic and local protections.
• Supervisory level — SCADA itself: the data acquisition server, mimic diagrams, the historian and alarms.
• Communication network — the Modbus RTU/TCP, OPC UA and Ethernet protocols over which the levels exchange data.

The main functions of SCADA

• Acquisition and archiving of data from instruments and controllers.
• Visualization in the form of mimic diagrams — clear schematics of the facility with «live» values.
• Trends — graphs of how parameters change over time, for analysis and root-cause investigation.
• Alarms and notifications when parameters go out of bounds and when faults occur.
• Remote control of equipment and changing of setpoints.
• Event and operator-action logs, reports, and access control.

What a mimic diagram is

A mimic diagram is a graphical representation of the facility on screen: pipelines, pumps, tanks and valves with real values of temperature, pressure and «on/off» states. A good mimic diagram lets the operator grasp in seconds what is happening and where a problem has arisen. A bad one does the opposite — hiding what matters behind excessive graphics; that is why we treat screen design as a separate engineering task.

Trends and the historian — why store history

SCADA continuously records parameter values. Trends show how the temperature changed over the day, when a pump started more often than usual, and at what moment the pressure began to rise. This is invaluable when investigating faults and when tuning energy-efficient modes: decisions are made from data, not «by eye».

Alarms: why sound configuration matters

If you set up alarms «head-on» — one for every minor deviation — the operator will drown in a flood of false alarms and stop reacting to them (the so-called «alarm flood»). That is why modern systems build alarming to the ISA-18.2 standard: with prioritization (which alarms are more important), acknowledgement (the operator confirms they have seen it) and a log. This reduces accident rates and human error.

Where SCADA is used

• Boiler houses, heat substations (ITPs), heating and hot-water supply systems.
• Water-supply and fire-fighting pumping stations.
• Ventilation, air conditioning, building engineering systems (BMS).
• Industrial production, power generation and infrastructure facilities.

SCADA and remote supervisory control

Modern SCADA is not tied to a single computer in the control room. For example, Atlas’s own supervisory server lets you monitor a facility’s engineering systems from anywhere, 24/7 — through a browser, from a computer or a phone. This is convenient for distributed facilities and for service maintenance: a specialist sees the problem remotely and responds in advance, often before the on-site staff even notice it.

How SCADA differs from automation and BMS

• Automation — local control of specific equipment by a controller.
• SCADA — a system for monitoring and controlling an entire facility (or several) from the top level.
• BMS (Building Management System) — a special case of supervisory control for a building’s engineering systems.

How SCADA is implemented — briefly, stage by stage

First you determine what data to collect and over which protocols; then you design the architecture and screens, configure controller polling, tags, trends and alarms, after which the system is commissioned on site and the staff are trained. The quality of the result depends not on how «pretty» the picture is, but on how well-thought-out the tags, alarming and communication reliability are.

The key points in brief

SCADA is the operator’s «eyes and hands» at a distance. It collects data, shows the state of the facility, warns of faults and lets you control processes. A well-designed SCADA system improves reliability, reduces operating costs and makes the facility’s operation transparent.

Atlas Scada designs and implements SCADA systems and supervisory control of engineering systems in Astana and across Kazakhstan — from sensor to server. If you need supervisory control of a facility or modernization of an existing system, tell us about your task — we will help you choose a solution.