In modern instrumentation, which gauge is commonly used for direct digital readouts and PLC/SCADA interfacing?

• A. Electrical gauge
• B. Analog gauge
• C. Digital gauge
• D. Mechanical gauge

Answer: (C)

Digital gauges are built to provide numeric, digital outputs that can be read straight by controllers and SCADA systems. This enables direct digital readouts on a display and straightforward data exchange with PLCs/SCADA, using common digital communication protocols. Analog gauges produce a continuous signal that needs conversion to digital form, adding potential error and extra hardware like ADCs. Mechanical gauges are purely physical and require measurement to be read manually or via sensors that convert to digital separately. The term electrical gauge isn't a standard category for digital interfacing and doesn't imply built-in digital output. So the gauge that best matches the needs of direct digital readouts and PLC/SCADA interfacing is the digital gauge.