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
Rangeable DP Sensors - Rangeable differential pressure (DP) sensors provide a high degree of flexibility in measurement applications by allowing users to adjust the output signal.
Wireless environmental sensors with custom MQTT SCADA system for energy management IoT platform - An energy management specialist required a multi-point wireless sensor network with specific accuracy requirements and a gateway that could output to their own MQTT-based SCADA system. This explains the selection of sensors and the dual gateway solution offered, covering both Modbus RTU and cellular MQTT options.
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
10 mbar range differential pressure calibrator - Calibrate 10 mbar differential pressure transmitters with this portable, high-accuracy calibrator featuring a built-in pressure controller.
DPT200 High One Side Overload Differential Pressure Sensor - DP transmitter for measuring pressure difference between two pressure points which can tolerate up a very high overload pressure independently on either the positive or negative side port or both together at the same time.
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DPT100 Modbus RTU RS485 Differential Pressure Sensor - The DPT 100 is a high-accuracy differential pressure transmitter designed for fast test processes in leakage and flow measurement applications where rapid response time and high sampling rates are essential
DPS Low Differential Pressure Transmitter - Ultra low differential pressure transmitter for HVAC applications with 4-20mA current loop or amplified voltage output signal in pressure ranges from 0.1 mb up to 1 bar differential.
Related Help Guides
- Measuring the difference in air pressure between rooms
- Measuring liquid level in a sealed tank with a hydrostatic pressure sensor
- Measuring vacuum with negative gauge or absolute ranges
- What is the difference between vacuum and absolute pressure
- Can you measure vacuum using a gauge pressure range
- 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
