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.
Minus 100 pascal suction pressure transmitter
Bidirectional -50 to +50 Pa diff pressure transmitter with user calibration adjustment
41X Low Range Digital Output Pressure Sensor
Differential Pressure Transmitters
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.
4 inch water column range 4-20mA differential pressure sensor for liquids- Minus 100 pascal suction pressure transmitter
70 bar range dp transmitter with a 450 bar overpressure rating in both directions
1.5 inWG differential pressure transducer to control positive pressure inside a building
- 100mb leak testing dp transmitter with 1mb accuracy & 10bar overpressure rating
- DPT200 High One Side Overload Differential Pressure Sensor
LEO Record (Ei) Capo Low Pressure Logger
150 Pa low range differential pressure switch and indicator