IoT-Based SCADA vs. PLC-Based SCADA: A Comprehensive Comparison
Introduction
In the renewable energy sector, Supervisory Control and Data Acquisition (SCADA) systems are indispensable for monitoring, controlling, and optimizing solar power plants. A common question among EPCs, developers, and asset owners is:
What is the difference between an IoT-based SCADA and a PLC-based SCADA?
The answer lies not in the fundamental features—since both IoT-based and PLC-based SCADA systems are designed to execute the essential monitoring and control tasks—but in the extent of capabilities. IoT-based SCADA goes beyond traditional PLC-based systems, offering superior connectivity, flexibility, and integration with modern digital platforms.
Basic Features Every SCADA System Must Support
Whether IoT-based or PLC-based, an effective SCADA system should be compatible with the following functionalities:
- Controller Redundancy for reliability
- Digital I/O Configuration for flexible control
- Tripping of Breakers (DO) for safety
- DI/DO/AI Extensions for scalability
- Local Monitoring Screens for on-site visibility
- Real-Time Monitoring for performance tracking
- OPC Compatibility for third-party integration
- Internet Provision for remote connectivity
- Remote Controlling for O&M teams
- Direct Access for plant operators
- Substation-Level Monitoring for grid compliance
- Workstations (EWS & OWS) for centralized control
- Fail-Safe Conditions for critical operations
- Architecture Flexibility for plant expansion
- OFC Compatibility for fiber communication
- SLDC Integration for state load dispatch centres
- Local Server & Storage for data redundancy
- Old Data Availability for historical analysis
- Software/Firmware Upgradeability for lifecycle management
- Weather Station Integration for performance ratio analysis
- Networking Components (Gateways, Ethernet Switches, Media Converters – BOM) for robust connectivity
Both IoT-based and PLC-based SCADA systems are capable of supporting these features.
PLC-Based SCADA
PLC-based SCADA relies on Programmable Logic Controllers as its primary hardware. These systems are robust, time-tested, and well-suited for industrial automation tasks. Their strengths include ruggedness, low latency, and proven reliability in harsh operating environments.
However, PLC-based systems often come with certain limitations in today’s data-driven energy sector. They are not inherently designed for multi-cloud connectivity, advanced analytics, or integration with newer digital platforms, making them less adaptable in large-scale, distributed, or hybrid energy projects.
IoT-Based SCADA
IoT-based SCADA employs smart data loggers, gateways, and IoT protocols to achieve monitoring and control. While capable of performing all the functions listed above, it provides enhanced capabilities that extend beyond the scope of PLC-based systems.
For example, IoT-based SCADA can:
- Send Data to Multiple Clouds Simultaneously – including nodal agencies, utilities, and private dashboards.
- Support modern communication protocols such as FTP, MQTT, HTTPS, SFTP, and APIs, ensuring compatibility with digital platforms and third-party analytics tools.
- Offer scalable deployment across distributed solar plants and rooftop systems.
- Enable advanced data analytics and AI/ML integration for predictive O&M and performance optimization.
This makes IoT-based SCADA the preferred solution in modern renewable energy projects where connectivity, scalability, and regulatory reporting are as important as local control.
Choosing the Right Approach
Both PLC-based and IoT-based SCADA systems fulfill the core requirements of monitoring and control. PLC systems remain ideal for projects requiring rugged localized automation, while IoT-based SCADA delivers superior value in environments where multi-cloud data sharing, digital analytics, and flexible integration are essential.
Conclusion
The question is not whether IoT-based or PLC-based SCADA can support the necessary features—they both can. The difference lies in how far each can go in adapting to today’s evolving solar and hybrid energy landscape.
With capabilities such as multi-cloud data transmission, API-based integration, and scalability across distributed assets, IoT-based SCADA systems are proving to be the future-ready choice for developers and asset owners.
At SuryaLogix, we specialize in designing IoT-based SCADA systems that not only meet the basic requirements of plant monitoring but also empower stakeholders with advanced digital connectivity, real-time analytics, and regulatory compliance.
