Again and again, we are asked the question concerning the difference between an absolute pressure measurement and a gauge pressure measurement. To answer this question it helps to look at this is of gauge pressure and absolute pressure. The difference between the two measurements is then explained relatively simply and therefore also the decision of the correct measurement.
Definition of absolute pressure
Absolute pressure is really a pressure that is in accordance with the zero pressure in the empty, air-free space of the universe. This reference pressure may be the ideal or absolute vacuum. It is denoted with the subscript ?abs?: Underused .
Definition of gauge pressure
The gauge pressure is defined as the difference between an absolute pressure (Pabs) and the prevailing atmospheric pressure (Pamb). It really is denoted with the subscript ?e?: Pe and is calculated as follows: Pe = Pabs ? Pamb.
Absolute vs gauge pressure measurement
The difference between the two measurements is relatively easily clarified: in a gauge pressure measurement, it is usually the difference from the existing ambient pressure that is measured. However, Amazing with the elements and the height above sea level. A complete pressure measurement measures the difference from the perfect or absolute vacuum. This is the reason this measurement is independent of environmental influences such as for example weather or altitude. Which measurement is currently the right one?
In practice, both measurements could be differentiated the following: in most cases, the measuring task is to determine the gauge pressure. Because of this , this kind of sensor is most widely used. However, if a gauge pressure sensor can be used in an application where the actual measuring task would be to gauge the absolute pressure, the following additional errors should be expected:
+/- 30 mbar caused by changes in weather
up to 200 mbar when changing the location (e.g. from sea level to 2,000 m)
Based on the measuring range, these errors can be substantial (e.g. in pneumatics at a measuring selection of 1 bar) or negligible (in hydraulics at 400 bar).
Note
Should you be uncertain whether your measuring task needs a complete pressure or gauge pressure measurement, simply e mail us ? we?ll be glad to work with you.