This week’s SCADA software glossary will cover input methods that operators can use to interact with their SCADA HMI systems out in the field, or even on supervisory computers. Here are some of the basic input methods often found in the HMI SCADA world:
Touchscreen – The touchscreen is a device that is reactive to touch. With this type of interface, a GUI or graphic user interface will represent different functions within the SCADA or HMI system. Touching, dragging with the fingertips, or even typing on a virtual keyboard are all ways to interact with a touch screen. While there are many technologies of touchscreens some are resistive membrane, capacitive, Surface Acoustic Wave (SAW), infrared, strain gauge, and each have pros and cons.
Keyboard – A keyboard is a piece of hardware where alphanumerical information can be entered directly. Keyboards are usually associated with desktop or portable computers, and may not be available on HMI applications that use panels or virtual keyboards. Everyone is used to the desktop versions, there are many companies that produce rugged or waterproof versions.
Virtual Keyboard (or popup) – A virtual keyboard is a keyboard used in coordination with a mouse, touchscreen, or even an external keyboard. A virtual keyboard allows operators to input things like alert acknowledgments, enter information, or retrieve information.
Mouse – The mouse is a ubiquitous input device in SCADA HMI software. The mouse can be used to navigate a user interface, and interact with various aspects through clicking or dragging. Industrialized hose down versions of the mouse exist for harsh environments.
Keypad – A Keypad or membrane is often an input device for an industrial computer that is protected against harsh elements like high heat or corrosive material. With the keypad, alphanumeric and even directional interaction with the SCADA or HMI system can be maintained. Often desired for its physical feedback or click that a touchscreen doesn’t give.
Joystick – The joystick is similar to the mouse in that it allows directional interaction with the user interface, and may also have some clicking abilities. Users of SCADA software may use a joystick to toggle buttons on or off, or navigate through the interface where no alphanumeric input is required.