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A pressure gauge is the most reliable and affordable component used by several industries across the globe for pressure measurement. While it is available in both versions, it is smarter to choose a digital pressure gauge over an analog one for its excellent user convenience. A digital pressure gauge is suitable for a wide range of applications and industries, including hydraulics/pneumatics, mechanical engineering, pumps/compressors, and general test operations. If you are planning to shop one for your automotive purposes like measuring the accurate reading of your tire’s air pressure then the digital air pressure gauges are the best partner of your the air compressors. Although before buying it you need to consider different aspects of it to avoid any negative consequences that can occur by choosing the wrong one. We will be discussing these aspects into three categories below which you must take care of while purchasing a digital air pressure gauge. Now it’s time get an insight into each of these.
Table of Content
Performance Related Aspects
In this section, we will be discussing some of the factors that have an impact on the performance of the digital pressure gauge. If you find everything alright with these performance issues then you are most welcome to buy that one.
Error Handling: If you have to measure anything pressuring high in magnitude you have to be spot on with your gauge selection to avoid any kinds of occasional human errors as it can badly hamper your safety or the result. To handle errors and ensure safety, the gauge should:
- Issue warning when the pressure exceeds the limit.
- have a safety measure in case of overpressure.
- Restrict the zero range
- Continuously display live pressure
- Stop displaying pressure when the sensor gets damaged.
- Provide a simple interface that clearly displays current unit for user’s convenience in order to prevent them from doing any mistake
- Limit features to specific user needs
- Be compatible while sustaining damage like getting dropped or any rough treatment
User Friendliness: A good pressure gauge comes with an easy and user-friendly interface which can be used even without a manual.
Custom Functions: Digital gauges are not only about mechanical parts rather it is the electronic firmware that really matters. For the reason that it allows the gauges for different custom functions some of which are:
- Testing Pressure Safety Valve: It is important to check if the gauge can operate at high read rate in order to test pressure safety valve effectively; this high reading rate seems consistent for some but others use a special mode to boost the read rate for this purpose.
- Testing Pressure Switch: The legislation of testing pressure switch for some applications like compressor stations, require the maintenance of a permanent testing record. A custom function that stores data to the pressure gauge makes it the pressure gauge an ideal one for such cases.
- Digital data-logging: A digital pressure gauge eliminates the analog chart recorder for data logging as it digitally stores data logs for long-term use that are also exportable as different data files like Excel, CSV or text files. For this functionality, it should also safe enough and should be IP-67 (waterproof down to three feet)
- Custom Units: A good digital pressure gauge allows custom pressure unit to be created in users specific readings like feet of seawater or feet-lbs.
Computer Interfacing: A great digital gauge comes with an Rs-232 or USB connector and respective software for allowing user for real-time data acquisition or continuous logging while getting it interfaced with the computer.
Accuracy Related Aspects
Accuracy is the most important factor of a digital pressure gauge. It expresses how closure it is to the measured value of the gauge. Some aspects related to this are discussed below.
- Accuracy Measurement: For a digital pressure gauge, accuracy is measured in relation to the full scale of the pressure gauge. One of the major confusion that can occur is because of the manufacturer’s convention used for the measurement. When they define the accuracy as ‘percent of span,’ it means the accuracy is a percentage of the gauge’s full-scale. For instance, a 100-PSI gauge with a 0.1 percent of span accuracy is accurate to +/-0.1 PSI across the entire range. By convention, the 0.1 percent-gauge is meant to be a 0.1 percent of span gauge. On the contrary, ‘percent of reading,’ means the accuracy is a percentage of the reading currently displayed. For example, 0.1 percent accuracy reading displaying 100 PSI is accurate to +/-0.1 PSI at that pressure. At 50 PSI, the same will have an accuracy of +/-0.05 PSI. Today, a digital pressure gauge displays readings with proper resolution across the entire range uses ‘percent of reading’ convention.
- Display Resolution: Resolution is the fineness of a display. Essentially, resolution signifies the number of the smallest equal pieces used to display the accuracy. Using for any industrial application such as a digital pressure gauge with a display range of 50.00 psi has a resolution of 0.01 psi (two decimal places). That is 1 count out of 5000. In some digital gauges, the least significant digit doesn’t change in increments as expected due to poor resolution, that is mainly noticeable for the least measurement like the millimeter or Kpa. You may also find another problem with the “floating point decimal.” Gauges with inadequate resolution may add a decimal place based on the pressure displayed that does not signify the perfect accuracy.
- Impact of Temperature: Temperature is an important factor that can affect the accuracy of your digital pressure gauge readings while working outdoors. To avoid these your gauge should have the required specifications. Anything with a narrow temperature operating band like 18C to 28C means it has inadequate temperature compensation. In such cases, gauges should have an in-built temperature compensation designed by the manufacturer.
- Factory Calibration: The factory calibration is the chance for the manufacturer to showcase the performance claims made in the gauge”s specification. You should check the factory calibration certificate to see the quality and specifications of calibration and re-calibration.
- Calibration Interval: A gauge with shorter calibration intervals like 90 days or less, provides the best performance.
- Certificate: Calibration certificate comes free, as nowadays instruments are manufactured using NIST-traceable automated calibration device. In this case, ISO 17025-accredited calibration lab is the ones to look for.
- Calibration: You can check the possibility to have an in-house gauge calibration as a calibration lab cannot help in case of the factory calibration.
Construction Related Aspects
To get the best digital pressure gauge you certainly need to determine few things about its Construction. You need these components to be compatible with different odds in order to meet the high standards for your job. Few elements and their issues are discussed here.
- Sensor Elements
- Welded: It’s important to make sure that the sensors are welded which generally harder to decide and need manufacturer’s confirmation. Although non-welded sensors use O-rings indicating ‘not for oxygen services’. These O-rings and thread types used by sensors have shortcomings like potential leaks if anything other than air or nitrogen is used.
- Moisture: Moisture or liquid water will eventually cause sensor failure, so you have to choose the pressure gauge having an isolating diaphragm that is suitable for such situations and does not demand dry or clean air to be used.
- Diaphragm: As said earlier, sensors with isolating diaphragms are gas/liquid compatible and protect damage. So look for one that has this feature.
- Technology: Piezoresistive sensors with oil isolation feature offer the performance and value required for handing overpressure. Sensors employing bonded stress gauges depend on the deformation of a metal diaphragm making them work like mechanical pressure gauges.
Also, the sensors need to be tested for low-cost digital pressure gauge by observing how they react to rapid pressure changes.
- Enclosures: The enclosure should be compatible with the digital hydraulic pressure gauge. Hydraulic fluids can attack polycarbonates, so you need to look for a metal enclosure. Marine-grade materials are suitable for services near saltwater. LCD should be built in hard glass and plastic to avoid any damage by getting dropped. You need to make sure from the retailer what to be done if it gets dropped or gets damaged.
- Batteries: You need to check if the gauge’s battery meets the standards and the needs of the application. Lithium batteries are excellent to have but make sure the gauge allows easy replacements without making any damage during the replacement procedure.
Finally, the digital hydraulic pressure gauge is one of the most important tools you need in your industrial applications. The air compressor in the automotive industry largely connected with the use of a digital air pressure gauge. We hope this article covers all the questions that you have in mind regarding its user experience as you will not get these answers in the manuals or the brochures. Generally, the digital pressure gauge price does not bother as much as these factors do while buying one. So we hope this guide has helped to give the complete insight into these factors.