How to choose a digital differential pressure gauge?

Accurate measurement of differential pressure (Differential Pressure) is a critical component in industrial process control, heating, ventilation and air conditioning (HVAC), laboratory research, medical equipment and many other areas. Digital differential pressure gauges are gradually replacing traditional mechanical differential pressure gauges due to their high accuracy, easy readability and intelligence.

However, facing a wide range of products on the market, how to select a digital differential pressure gauge that best suits your application? This article will help you sort out the key selection steps and considerations to help you make an informed decision.

Before we make a selection, let’s get a few key terms straight:

– Differential Pressure : The difference in pressure between two pressure ports (the high pressure end and the low pressure end). This is the core measurement object of the differential pressure gauge.
– Range: The maximum pressure difference that a differential pressure gauge can measure. For example, 0-500 Pa or 0-100 kPa. Never allow the actual working pressure to exceed 150% of the range, or permanent damage to the sensor may result.
– Accuracy: Indicates the range of deviation between the measured value and the true value. Usually expressed as a percentage of full scale (FS), e.g. ±0.5% FS. The higher the accuracy, the more expensive it usually is.
– Resolution: The smallest change in pressure that can be shown on the display. The resolution of digital instruments is usually very high.

1. What is being measured?
– Gas or liquid? The type of medium directly determines the material compatibility of the sensor.
– Is the medium corrosive? For example, corrosive gases, vapors, or liquids require corrosion-resistant materials (e.g., 316L stainless steel, Hastelloy) for the parts that come in contact with the medium (e.g., pressure connections, diaphragms).
– Is the medium clean? If the medium contains dust, oil or particulate matter, it may be necessary to consider the addition of an isolation membrane or filter to protect the sensor.
2. What is the measuring range?
– Estimate the maximum differential pressure you need to measure. Select a differential pressure gauge with a range about 1.5 times higher than your maximum expected value. This will ensure measurement accuracy and provide some overpressure protection against accidental shock damage to the sensor. For example, if the maximum differential pressure is 200 Pa, a range of 0-300 Pa or 0-500 Pa would be appropriate.
3. How much accuracy is needed?
– Laboratory calibration or precision process control may require a high accuracy instrument of ±0.1% FS.
– For general filter pressure monitoring or ventilation system monitoring, ±1% FS or ±2% FS accuracy may be sufficient. There is no need to pay extra for excessive accuracy.
4. What are the environmental conditions?
– Temperature range: What ambient temperature does the instrument need to operate at? Extreme high or low temperatures can affect the performance of the electronics and battery life.
– Explosion-proof requirements: If flammable and explosive gases are present in the operating environment (e.g., petroleum, chemical industry), a model with explosion-proof certification (e.g., ATEX, IECEx) must be selected.
– Protection level: If the environment is dusty or humid, you need to pay attention to the IP protection level of the instrument (e.g. IP65 means dustproof and waterproof) to ensure that it can work reliably.

1. Display and units:
– Screen: Is it clear and easy to read? Is it backlit (for use in dimly lit environments)?
– Units: Does it support multiple pressure units (Pa, kPa, bar, psi, mmH₂O, inH₂O, etc.) and can they be freely switched?
2. Output and Communication:
– Analog Output: Do you need a 4-20mA or 0-10V analog signal output for connecting to a PLC, DCS or data acquisition system?
– Digital Interface: Do you need digital communication function such as RS485, Modbus, USB or Bluetooth to realize remote monitoring and data logging?
3. Power supply:
– Battery powered: Advantages include portability, flexibility, and suitability for on-site testing and temporary measurements. Battery life is a concern.
– DC/AC power supply: Suitable for fixed installation and long-term continuous monitoring.
4. Data Functions:
– Zero Clear (Tare): Very useful function to ignore the static pressure and measure only the differential pressure.
– Maximum / Minimum Value Recording: Automatic recording of peak values during measurement for easy analysis.
– Data logging/exporting: Advanced models may have built-in memory, allowing data to be logged over a period of time and exported for analysis via software. 5.
5. Mechanical design:
– Pressure connections: Is the size and type of connection (e.g., quick-connect, threaded) compatible with your piping?
– Mounting: Is it wall-mounted, panel-mounted, or hand-held?
– Body size and weight: Do you need portability?

• High-Precision Pressure Sensor
Fast response time with an accuracy of up to ±0.5%FS, precisely capturing subtle pressure changes.
(Measurement Range: -101Kpa ~ 200Kpa) (Measurement Accuracy: ±0.5%FS) (Measurement Resolution: 0.1Kpa)

• LCD Backlit Display
Easily read measurements for positive pressure, negative pressure, and differential pressure, even in bright or dim environments.

• Data Lock Function
One-button precise locking ensures stable, unchanged data, preventing accidental touches or environmental interference from affecting the readings.

（psi、inHg、Kpa、mbar、bar、mmHg）
• 6 Units Switch
Seamlessly switch between 6 pressure units anytime, without manual conversion, ensuring precise data presentation.
(psi, inHg, Kpa, mbar, bar, mmHg)

• Portable Design
Mini and compact, easy to operate, ideal for on-site testing and mobile use.

• Versatile Applications
Equipped with various measurement connectors, it accurately covers pressure testing for core systems such as intake, brakes, exhaust, and crankshaft, fully meeting automotive repair and diagnostic needs.

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Email: shop@autooltech.com