Pressure measurement and transmitters

Pressure can be defined as the amount of force applied per unit area (F/A). The processes in industry require accurate and reliable pressure measurements for safe operations and the production of quality products. The effects of pressure include position movements, changes in resistance, or other physical changes that can be measured. Common pressure sensors employ a Bourdon tube, diaphragm, bellows, force balance or variable, and a capacitance arrangement.

A pressure transmitter is required to produce a standard signal (4 to 20 mA or 0 to 10 V) from whatever pressure effect the sensor is based on. Mostly, a pressure transmitter comes with an inbuilt sensor and is sold as a single package, as shown in the following figure:

Figure 12.8 – A front view of a pressure transmitter (Credit: Showlight Technologies Ltd.: www.showlight.com.ng)

The following figure shows a simple connection to a pressure transmitter...