What is scada? Definition and Details paessler com/it-explained/scada it explained: scada back to index Content

SCADA alarming
Alarming is a key feature of SCADA systems. Alarms are notifications that inform
operators about an event and can range from routine maintenance reminders to
emergency alerts. Some common emergency SCADA alarm triggers are equipment

---

11/16
failure, system downtime, and deviations in desired device metrics. SCADA alarms may
provide notifications about underperformance and non-compliance. 
An alarm may trigger an automated response, for example notifying an operator of a loss
of power at a station and simultaneously activating a UPS and backup power supply
automatically.
SCADA vs IIoT
Sometimes SCADA is compared to the Industrial Internet of Things (IIoT) and some
commentators predict that IIoT applications will replace traditional SCADA systems.
Traditional SCADA systems and IoT applications in industrial environments perform the
same functions like monitoring machines, collecting data, responding to alerts, and
controlling field devices. However, there are a number of differences between them.
Traditional SCADA systems are designed for the day-to-day management of data at
industrial facilities. They lack the powerful analytic capabilities that IIoT systems excel at.
SCADA models are not designed to be fully compatible with multiple enterprise
applications as are IIoT systems. 
In most traditional SCADA systems, data is gathered using Open Platform
Communications (OPC) as a communication standard for the transmission of data from
field devices to the control center. IIoT systems use web-based services and APIs that
allow for the connection of disparate edge devices using protocols like Message Queuing
Telemetry Transport (MQTT), HTTPS, and REST. IIoT systems use smart gateways to
push data to a central hub.
The prevalence of proprietary devices in traditional SCADA systems reduces
interoperability, a feature of industrial automation that the IIoT has been specifically
designed to address. IIoT systems provide on-demand scalability using serverless
architectures. Traditional SCADA systems use wired connections and are based on-
premise whereas IIoT systems use wireless connections and are cloud based. Traditional
SCADA systems are centralized whereas IIoT systems are decentralized.
Some organizations implement hybrid systems so that they can retain control of specific
data and processes. On-premise devices can be monitored through operator interface
terminals (OITs); dedicated terminals that display information about data and processes
on local devices and allow an operator to control local equipment on site.
Increasingly, IIoT applications are considered alternatives, not replacements, for
traditional SCADA systems and may be implemented on top of SCADA, reducing the
downsides of vendor lock-in like lack of standardization and interoperability. The IIoT may
allow organizations to retain legacy infrastructure, and enhance existing equipment
capabilities. One of the main benefits of integrating IIoT and SCADA systems is that

---

12/16
relatively simple SCADA measurements and device states can be analyzed by cloud
computing and machine learning applications, providing in-depth information about the
efficiency of a SCADA system.
Cloud-based SCADA systems are more cost-effective, as applications run in a virtual
environment obviate the need to keep certain hardware like PCs that run individual
software instances patched and updated.
Hybrid SCADA systems and IIoT platforms are capable of integrating data from different
types of devices and making them accessible from anywhere.