Smart human-machine interfaces (HMIs) can securely tie servers, controllers, and input/output (I/O) devices together, inside and outside the plant. There are many differences between embedded and PC-based HMIs and it is important to know them to find the right fit for a particular system.
An embedded HMI runs on an embedded operating system and is dedicated to one function of hosting the HMI application and requires fewer computing resources than a PC-based HMI. a PC-based HMI is more powerful, expandable, and flexible; but it is also expensive to purchase, install, and support and consume tremendous amounts of resources.
When used as a communication hub, many disparate machines or technologies may be used and need to be connected, and using a PC-based HMI/SCADA node is often the preferred choice in this circumstance. [SCADA stands for supervisory control and data acquisition.]
Modern embedded HMI’s are becoming more flexible and easier to connect to other components. Built-in web server capability and support of HTML5 browsers provides freedom from previous custom programming requirements. Support for the HTML5 standard within the embedded HMI platform allows creation of graphics that can be accessed by any web browser hosted on virtually any remote device, providing nearly universal Internet of Things (IoT) connectivity.
Two of the main capabilities setting PC-based HMIs apart from embedded HMIs are connectivity and data handling. Although an embedded HMI can handle a considerable amount of data related to the application it’s monitoring, in larger applications, a PC-based HMI can serve as a hub for database storage and information dispersal.
>Read more by Marcia Gadbois, Control Engineering, 12/4/15