What are SCADA systems and how do they work?

The daily functions we sometimes overlook—like water management, power generation, and manufacturing—depend heavily on automation. At the heart of this automation lies the Supervisory Control and Data Acquisition system, also known as SCADA.

When dealing with SCADA systems, the stakes are high. Beyond just controlling equipment, SCADA systems can be guardians of public safety and stewards of valuable resources. For utilities like the water and wastewater field, modern systems help protect the public. They reduce human error and ensure reliable water services. These systems also prevent spills and avoid contamination events.

When a strong system uses digital transformation tools well, it can be a source of value and performance. This is especially true when it works with skilled and experienced operators. Although a well-maintained system requires continual investment, the payoff becomes evident through the ease of staff operations and the reductions in costs for treating and delivering water.

What is SCADA?

SCADA is frequently used interchangeably with “industrial control system.” However, it is actually a subsystem that manages data collection and the presentation of graphical interfaces. SCADA used to mean just screens and data. Now, it includes networking equipment and programmable logic controllers (PLCs).

As a system of software and hardware elements, SCADA allows industrial organizations to:

• Control industrial processes locally or at remote locations
• Monitor, gather, and process real-time data
• Directly interact with devices such as sensors, valves, pumps, motors, and more through human-machine interface (HMI) software
• Record events and information into log files or databases

SCADA typically consists of seven components:

1. Field instrumentation: Sensors and actuators that link the control system to the physical process. Communication occurs over protocols such as serial, Ethernet, 4–20 mA, or other systems.
2. PLCs: Industrial computing devices that execute the logic to orchestrate processes.
3. Human-Machine Interfaces (HMIs): Screens and touch-panels located near machinery for operators to monitor and control processes.
4. Telemetry and communications infrastructure: The fabric that ties all the components of the control system together. Made up of switches, firewalls, point-to-point radios, fiber optics, cables, or other networking system.
5. Servers and datastores: Hardware for hosting virtual machines, databases, and software applications.
6. Virtual machines: Computing systems that share physical hardware and each exist separately to execute specific functions.
7. SCADA clients: Interfaces such as workstations, thin clients, tablets, or laptops that are used to control the system, usually in an office or control room environment.

Segmentation

Dividing SCADA networks into specific functional zones is essential for boosting cybersecurity and the efficiency of industrial control systems. This organized method minimizes the attack surface, enhances data flow management, and optimizes system performance by arranging the system into separate layers. In adherence to the Purdue Enterprise Reference Architecture, this is how we recommend segmenting your network:

• Level 0: The physical process, such as water treatment and pumping.
• Level 1: Intelligent devices, including PLCs, which automate control by executing logic based on sensor inputs.
• Level 2: SCADA systems providing real-time monitoring and control, visualizing data from PLCs, and allowing operator interaction.
• Level 3: Data historians and reporting tools, which archive operational data for trend analysis, regulatory compliance, and performance reporting.
• Level 4: Business logistics systems, integrating SCADA data with enterprise resource planning (ERP) and business management tools.

Virtualization in SCADA systems

Virtualization has emerged as a crucial technology in contemporary systems, allowing organizations to manage control systems with greater efficiency. By simulating physical hardware, multiple virtual machines (VMs) can run on a single physical server, resulting in improved efficiency, scalability, and cost savings. Traditionally, SCADA systems depended on dedicated physical hardware, which presented challenges like limited capacity, high maintenance expenses, and complicated redundancy configurations. Virtualization resolves these problems by separating SCADA software from the hardware, enabling dynamic resource allocation and more effective use of infrastructure.

The key benefits of virtualization include:

• Scalability: New VMs can be quickly deployed to meet growing demands without needing additional physical hardware.
• Maintenance: Virtual environments simplify updates and backups, minimizing downtime.
• Disaster Recovery: VMs can be easily replicated and restored, enhancing recovery processes.
• Security: Virtualization adds security by making it feasible to isolate system functions to dedicated VMs and by providing features like access control and encryption.

Virtualization enhances SCADA system efficiency, providing cost reductions, increased adaptability, and enhanced disaster recovery, while promoting collaboration between IT and operations teams.

Developing a system

To develop an effective SCADA system, organizations optimize long-term value by following a structured process:

1. Find the right team: Seek out a qualified integration partner and/or ensure your in-house team is capable and committed.
2. Define system objectives: What should your control system achieve?
3. Create a SCADA master plan or roadmap. This plan gives clear guidance for deploying the system step by step over several years.