Which arrangement is used to measure differential pressure in a system?

• A. A single port gauge pressure sensor
• B. A temperature-compensated absolute pressure sensor
• C. A gauge pressure transmitter connected to one port
• D. A differential pressure transmitter connected across two ports

Answer: (D)

Measuring differential pressure requires comparing two pressure points with a sensor that accepts two inputs. The arrangement that does this is a differential pressure transmitter connected across two ports. It has two sensing paths and outputs a signal proportional to the pressure difference between them, making it ideal for applications like monitoring flow restrictions, filter condition, or level across a pair of taps.

The other options don’t provide a pressure difference measurement: a single port gauge sensor measures pressure relative to atmosphere at one point; a temperature-compensated absolute sensor measures absolute pressure at one point (relative to vacuum); and a gauge transmitter tied to one port only captures the pressure at that single port, not the difference between two points.