Learn how a differential pressure sensor (dp sensor) can be used to measure a partial vacuum as a negative pressure relative to local surrounding air pressure.
Measurement & Instrumentation Guides
Guidance and reference articles for sourcing, setting up and using measurement equipment.
Measuring vacuum as an absolute range using a dp sensor
Find out how to use a differential pressure sensor (dp sensor) to measure a partial vacuum as a positive pressure relative to full vacuum.
Can you have a minus 20 psi gauge vacuum measurement range
Is it possible to have a vacuum pressure measurement device with a -20 to +50 psi gauge pressure range, since I’ve never seen a pressure instrument with a range greater than -15 psi?
Output signal orientation for a negative gauge pressure range
Since a negative pressure range works backwards to a positive gauge or an absolute pressure range, and that zero pressure corresponds to a full scale measurement, it has led to the use of both a forward and reverse output signal to measure suction or vacuum pressure in relation to ambient atmospheric air pressure.
Measuring negative pressure using a positive differential pressure range
How can you use a differential pressure measurement device to measure a negative pressure if it has been factory configured to measure a positive pressure range without making any adjustments to the electronics or the signal output?
What does negative and positive gauge pressure mean
You may not be aware but nearly every pressure measurement device you are using has a positive or negative gauge reference.
Can you measure vacuum using a gauge pressure range
The most common type of pressure range for pressure measurement instrumentation is one which has a gauge reference. So if you want to measure vacuum pressure, it would be convenient to use a gauge pressure device which is the most widely available pressure range format.
What is the difference between vacuum and absolute pressure
Often you will see a measurement of vacuum pressure described as an absolute pressure reading, so is there any difference between the two?
Negative Gauge Pressure
Negative Gauge Pressure is the difference in pressure between any vacuum and atmospheric pressure. The maximum possible negative gauge pressure is always limited by the current ambient atmospheric pressure, which constantly varies, but is typically around 1 bar absolute.
Suction Pressure
Suction pressure is a negative difference in pressure generated between two points which draws a gas or a liquid from a higher to a lower pressure state.
Vacuum
This guide provides an overview of measuring vacuum pressure including suggested vacuum measurement products and question & answers.
Measuring vacuum with negative gauge or absolute ranges
There are two reference points for measuring a vacuum pressure.