Which of the following devices is NOT typically considered part of a SCADA system?

In the context of SCADA (Supervisory Control and Data Acquisition) systems, data visualization software is typically not considered a core component of the system itself. SCADA primarily consists of hardware and software components that allow for real-time monitoring and control of industrial processes.

Programmable Logic Controllers (PLCs) and Remote Telemetry Units (RTUs) are integral to SCADA systems. PLCs are specialized computers used for automation of industrial processes and provide control functions, while RTUs serve as remote devices that capture data from field instruments and transmit it back to the SCADA system for monitoring and control.

Human-Machine Interfaces (HMIs) act as the interface through which operators interact with the SCADA system, allowing them to visualize the system's state and control processes.

Data visualization software, while it may assist in interpreting the data gathered by SCADA systems, is not part of the underlying architecture that enables the collection and control functions. Thus, it does not fit the definition of the core components found in a SCADA system.