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
Low Range DP Sensors - Low range differential pressure sensors for measuring very small pressure differences.
10 mmWC draft fan differential pressure transmitter - Low range dp transmitter for measuring 0... -10mmWC to maintain constant negative pressure across an induced draft fan fitted with a variable frequency drive.
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
Airflow and chamber pressure measurement for a portable modbus data acquisition trolley - Differential pressure sensor and a analogue signal to Modbus RTU RS-485 converter provided a flexible solution for measuring bidirectional pressures from a test chamber and an orifice plate on a mobile test rig.
DPS200 HVAC Differential Pressure Transmitter - Differential air pressure sensor with a 10 volt or a 4-20mA output for building ventilation applications. Ranges from 0 to 6 mbar up to 0 to 1000 mbar.
Featured differential pressure measurement products
- Measuring HVAC plenum and sub-floor air pressure in data centers - Monitoring the critical air pressure gradients in data center sub-floors, server rooms, and ceiling plenums. Low range differential pressure transmitter provides stable gauge pressure readings for optimizing HVAC and cooling efficiency.
- Monitoring data center positive pressure with a low-range differential transducer - Low-range differential pressure transducer for verifying and monitoring critical positive air pressure between a data center equipment room and adjacent areas, ensuring compliance with required ≥5 Pa and ≥10 Pa thresholds.
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
Related Product and Application Guides
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
Related Product Types
Differential Pressure Transmitters
Vacuum Pressure Transmitters
Vacuum, Suction Pressure Data Loggers, Recorders
Digital Interface DP Sensors
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