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
Clean room monitoring system to measure pressure, humidity & temperature in 4 individual rooms - A complete clean room measurement system for 4 separate rooms, each with its own room pressure, humidity and air temperature indicator, and a central monitoring unit for clean room corridor or control room.
20 Pa DP range 0-10V output air pressure sensor for building management use - A low range 20 Pa range differential pressure sensor, ideal for monitoring filters, ventilation ducts, and HVAC systems in commercial and residential buildings.
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
Air DP Sensors - Air differential pressure sensors play a vital role in maintaining environmental control and safety within critical applications such as cleanrooms, laminar flow cabinets, and ventilation systems.
Bidirectional -50 to +50 Pa diff pressure transmitter with user calibration adjustment - Enhance your hvac or filter monitoring system with this accurate and durable low differential pressure transmitter featuring user-adjustable zero and span.
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Wireless differential pressure monitoring for room overpressure using a modbus gateway - Monitoring room pressure differentials without running new cables by utilising 4-20mA DP sensor converted into a battery-powered wireless node that integrates directly into a local SCADA system via a Modbus RS485 gateway.
Digital Interface DP Sensors - Explore our range of differential pressure sensors featuring RS485, RS232, and USB digital interfaces.
Related Help Guides
- Measuring liquid level in a sealed tank with a hydrostatic pressure sensor
- Measuring vacuum with negative gauge or absolute ranges
- Measuring the difference in air pressure between rooms
- 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
- Differential Pressure
- Dry/Dry
- Negative Gauge Pressure
- Static Line Pressure
- Suction Pressure
- Vacuum
- Wet/Dry
- Wet/Wet
Related Online Tools
- DP Flow Transmitter Output Calculator
- High and Low Side Pressure to Differential Pressure Calculator
- Suction Pressure to Vacuum Calculator
