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?
Finding a pressure sensor to read negative pressure can be difficult since the vast majority of pressure measurement devices are only available with positive ranges as standard, since most applications require a positive pressure range, and therefore manufacturers understandably focus on the most popular pressure ranges for their product range.
Although manufacturers will often consider a custom configuration for measuring negative pressure, this could cause a delay to delivery and an extra cost compared to the standard pressure range configuration.
Featured differential pressure measurement products
ADT681 Digital Pressure Gauge - The ADT681 digital pressure gauge family covers a wide range of pressures from as low as 1 inH20 differential to as high as 36,000 psi gauge.
Vacuum pump inlet to outlet differential pressure sensor with 1500 Torr range - Differential pressure sensor to measure the differential pressure between the inlet and outlet of a vacuum pump.
There is a much simpler and convenient solution to measuring negative pressures. A differential pressure measurement device has two separate pressure connections so that the difference in pressure between the two connections can be measured. One connection will be marked as High (Hi) or Positive (+), and the other as Low (Lo) or Negative (-).
Typically when measuring positive pressures, the Low side connection would be open to ambient air pressure, and the High side connection would be connected to the positive pressure to be measured.
If you want to measure negative or suction pressure instead, you can reverse the connection, so that the High side connection is open to ambient air pressure, and the Low side connection is connected to the vacuum pressure. As the vacuum increases, the greater will be the difference in pressure between the Low and High side.
As an example, a 0 to +100 mbar differential pressure range will become a 0 to -100 mbar differential pressure range simply by reversing the connections.
Featured differential pressure measurement products
Engine test cell fuel filter 2.5 bar differential pressure sensor with ATEX approval - Sensor to measure differential pressure across fuel filters in an engine test cell on diesel and kerosene.
Low Range DP Sensors - Low range differential pressure sensors for measuring very small pressure differences.
Featured differential pressure measurement products
Pressure Calibrator for Pressure Transmitter Calibration – ADT672 - The ADT672 series of pressure calibrators are precision digital pressure gauges with electrical measurement for pressure transmitter calibration- Balancing air pressure in marine engine rooms with a low range dp sensor - Low-range bidirectional differential pressure sensor helps maintain the critical air balance in a sealed vessel engine room, ensuring optimal engine combustion and ventilation performance.
Related Help Guides
- Measuring vacuum with negative gauge or absolute ranges
- Measuring the difference in air pressure between rooms
- Measuring liquid level in a sealed tank with a hydrostatic pressure sensor
- What is the difference between vacuum and absolute pressure
- What does negative and positive gauge pressure mean
- Measuring vacuum as a negative gauge pressure using a dp sensor
- Measuring liquid level in a tank using a dp sensor
- Measuring density of a liquid using a dp sensor
Related Technical Terms
Related Online Tools
- DP Flow Transmitter Output Calculator
- High and Low Side Pressure to Differential Pressure Calculator
- Suction Pressure to Vacuum Calculator
Related Product and Application Guides
Related Application Questions and Answers
- Air Replacement Plant (ARP) 100 mm H2O differential pressure transmitter
- Vacuum drying pressure data logger
- Low range vacuum pressure logger for 0 to -60 inH2O g
- High reading rate for measuring dynamic pressures to -200psf
- Using 25 mbar DP sensor on vacuum below 0.2 bar absolute
- Low range ATEX approved 100 Pascal range DP transmitter
- Biogas HDPE cover PD blower pressure sensor
- Engine test cell fuel filter 2.5 bar differential pressure sensor with ATEX approval
- USB pressure sensors for detecting water leaks & restrictions
- Leak testing set for checking 1mb/min drop at negative 10 mbar vacuum
- Vacuum suction sensor & wall mount digital readout with switched contacts
- Solvent compatible +/-100mWG dp transmitter with PTFE seals
Contact us about this Measuring negative pressure using a positive differential pressure range page to request more information, or to discuss your application requirements.