Using a pressure measurement instrument to measure fuel level is very common, however most are scaled in bar or psi pressure ranges, and if they do happen to be scaled in level units, they are typically water level based, such as mH2O or ftH2O.
Measurement and instrumentation help guides
You may not be aware but nearly every pressure measurement device you are using has a positive or negative gauge reference.
The most common type of pressure range for pressure measurement instrumentation is one which has a gauge reference. So if you want to measure vacuum pressure, it would be convenient to use a gauge pressure device which is the most widely available pressure range format.
Often you will see a measurement of vacuum pressure described as an absolute pressure reading, so is there any difference between the two?
One of the most common measurements on any machine or process is pressure. Air, gas and liquids are used extensively on many types of machines as the medium used to operate moving parts.
Work out what pressure gauge is needed based on the bore size of the cylinder and the maximum force generated by a press.
Measurement and point detection devices for monitoring liquid level and activating switch contacts at predetermined liquid level thresholds.
Instrumentation for measuring the motion of a substance as it passes through a pipe or duct.
This article explores the many advantages of wired sensors compared to wireless sensors in order to help you make a decision on whether to opt for a wireless sensor network over a wired sensor installation.
It is not possible to measure the volume directly, and unfortunately there is no such device as a volume sensor, however if you know the dimensions of the space filled with liquid, you can easily determine the volume.
Before purchasing a pressure sensor, there are a number of application questions you will need to answer to ensure it is fit for purpose
How do I convert the pressure reading to quantity of milk at bottom temperature which varies approx 10 deg C
Why we mainly use 4-20 mA current and 3-15 psig pressure and not use from zero to 20 mA or 15 psig?
How do you use a dp cell measuring a span of 0-500 mmH2O with an o/p of 4-20 mA to control a flow rate of 0-1000 L/h for a flow meter range?
Zero Offset relates to the zero setting tolerance during manufacture and Zero Drift relates to the expected maximum change in zero over time.
When specifying the electrical connection for the DMP, DMK, LMP and LMK series of pressure/level transmitters you will need to choose from a selection of cable types.
Sealed gauge or SG is a type of pressure reference typically used when a vented reference is not possible because of the type of sensing technology or the need to provide secondary containment overpressure protection.
This is a list of web resources for checking the compatibility of materials with different liquids and gases.
Gauge reference pressure measuring devices read pressure relative to atmospheric pressure. This ensures that the pressure reading is nominally zero when the pressure on the device is released.
Questions and answers about liquid level measurement
We are trying to simulate an environment of 8000 feet in altitude inside a cylinder. We are located in an area that is 200 feet above sea level.
How do you calculate maximum gauge error in pressure measurement with a bourdon gauge instrument?
We have a horizontal cylindrical type tank which has a diameter of 2 meter and a length of 7 meters. This tank is used for storage of chemicals.
I have a 4 to 20mA pressure sensor, is there a way of converting the output to a 10 volt signal so I can use a voltage input data acquisition card?
I have a 10bar pressure transducer with a 4-20mA output which is showing a random variation across a span of 0.3mA (+/- 1.5mA) at a fixed pressure.
I‘m having a problem zeroing a submersible pressure sensor. Before placing it in the water, the zero offset is trimmed on the indicator, and then it is submerged to full range depth of 10 metres. During the first few minutes we notice that the full scale reading drifts by about 10mm in the negative direction […]
In the case of load cell calibration how is the value of shunt resistor defined? Does it depend on the capacity of the load cell? It’s not a function of load directly, the shunt resistance for calibration of a load cell is dependent on the strain gauge bridge resistance and the output sensitivity of the […]
What is the method of shunt calibration in relation to an indicator connected to a pressure transducer?
A hydrostatic level probe typically uses pressure sensor to measure the water level. The main component of a pressure sensor is the sensing diaphragm which converts the difference in pressure between either side of the diaphragm into a measured signal. The front of the diaphragm measures the water level pressure (hydrostatic pressure) plus the barometric […]
Questions and answers about temperature measurement
Can a pressure measurement device be used to measure the volume in a rainwater harvesting tank?
I have a confusion regarding the difference between the maximum working pressure, overpressure and burst pressure for pressure transmitters.
I have level data from a non-vented transducer & barometric pressure data, how do I determine the true depth?
Find answers to questions about process connections used to install measurement instrumentation.
Flow measurement online tools, help guides, products types, questions and answers.
A 4-20mA current signal has become very popular for many applications beyond it’s original intended purpose in the process industry. It is now used throughout industry as the preferred measurement and control signal for many different types of systems. Despite the popularity of the 4-20mA signal, it is not the best solution for every application […]
It is not unusual for a pressure measurement device to read slightly above or below zero with no pressure applied.
All devices connected to make up a 4 to 20 milliamp current loop are connected in series.
It is possible to view part of the diaphragm on most pressure transducers and some which are completely exposed such as flush diaphragms are particular vulnerable to mechanical damage.
There are many contributing error factors which go into a total uncertainty calculation. The way accuracy is defined for pressure instruments on technical data sheets can vary significantly across manufacturers and product types.
Explanations for product markings found on ATEX approved equipment. ATEX is the regulatory directive for the use of products in explosive atmospheres.
There are a number of methods and technologies for measuring the level of a fluid with hydrostatic pressure transducers.
Installing pressure sensors close to high temperatures can lead to significant measurement errors and irreparable damage to the sensor & electronics.
It is often assumed that devices with an IP68 rating are suitable for immersing underwater for an indefinite period at any depth. Not all devices that are IP68 are intended to be continuously submerged, some only require a temporary rating to protect from occasional submersion. For example a pressure transmitter installed below ground level will […]
When it is necessary to present gauge reference pressure data, an absolute pressure sensor can be used in some situations if a gauge pressure sensor is not available. An absolute pressure sensor will measure total pressure independent of atmospheric pressure changes, unlike a gauge pressure sensor which measures pressure relative to atmospheric pressure. To convert […]
Deciding the correct length of cable for a suspended IP68 transducer is an important part of specifying, if the cable is too short it is difficult and expensive to join two cables together and make the seal liquid tight. There are two separate parts of the installation that need to be considered to determine the […]
Placing a sensing device in a liquid is one of the most hostile environments to ensure a long reliable service life. The extra considerations for design engineers include: Keeping pressurised liquid out. Preventing condensation damage to the internal electronics. Corrosion protection for all the materials used in the transducer construction. Adequate protection from lightning surges […]
If you are running a signal cable over a long distance or have a spare current output pressure transmitter, it is possible to convert the output signal to a voltage type to make it compatible with voltage only input devices. A typical current output is 2 wire 4 to 20 mA which is designed to […]
When selecting a part number for a pressure transmitter you will need to choose a pressure range. Usually a manufacturer will designate pressure ranges in the most common unit used by it’s customers. For the USA the most common unit is psi and for Europe it is bar, but what if you are working with […]
In recent years regulations for environmental control, health and safety issues have become much more stringent for existing and new landfill sites. The regulations encompass many considerations and some involve the measurement and control of water level in many positions around a waste disposal site. One application is ensuring contaminated water is contained within a […]
The value of hydrostatic pressure for a fixed height column of fluid is directly proportional to the gravitational strength at a particular geographical location. Generally if the height above sea level is increased the hydrostatic pressure will decrease. Also since the world is wider at the equator than the poles the gravitational pull will increase […]
Any pressure transducer which relies on a force collecting diaphragm for sensing pressure, will be sensitive to a change in orientation. A pressure transducer diaphragm is designed to flex when a force is applied to it. If the diaphragm is orientated horizontally it will sag slightly under the force of its own weight. If the […]
We occasionally receive requests for combinations of pressure sensor features that are not practical to include in the same specification. Below is a list of the most requested parameter combinations that are declined including explanations. Low Pressure Range with High Media Temperature – the thin and large diameter diaphragms used in the construction of low […]
There is a loose convention across manufacturers for designating the type of reference that a pressure sensing device has, which can be confusing if you are unfamiliar with specifying this often overlooked but critical specification parameter.
Monitoring and controlling the pressure in a room is a critical parameter in many indoor environments where the climate must be maintained at a particular temperature, humidity and cleanliness/containment level.
When selecting pressure sensor options, occasionally you will come across a choice of seal materials to choose depending on the sensor design. An all welded construction provides a high integrity and homogeneous material design. The main disadvantages of this kind of sensor design is the lack of flexibility to customise for different applications, induced measurement […]
Most air hand pumps that are designed to be used as pressure calibrators include a coarse pressure generator and a fine pressure adjuster. The effectiveness of both is dependent on the test volume connected to the pump. The coarse or main pressure generator is typically a piston and cylinder arrangement which is actuated either by […]
When browsing through pressure measurement products you will notice that some are called pressure transducers and others are called pressure transmitters.
Determining whether you need gauge or absolute reference pressure is a very important to selecting the right pressure range for a pressure instrumentation.
Submersible cable is more expensive because it has to be reinforced to support the sensor plus its own weight in deep holes without stretching which would lead to a change in sensor position and ultimately sensor calibration. A submersible cable also has a vent tube running through it to allow gauge reference pressure sensors access […]
By their nature low range pressure sensors are very sensitive instruments and there a few factors that need to be considered prior to and during installation.
In order for any pressure transmitter to function within designed performance levels, a min. supply voltage must be maintain device operation.
In order to measure the level of a liquid using a pressure sensor you must be able to subtract the pressure of the gas at the top of the tank.
Not even the most accurate pressure instruments will hold their accuracy indefinitely, all are prone to drift over time.
There are many ways to measure the height of a fluid and one of the most popular is to use a pressure sensor.
The first step in selecting a pressure transmitter for liquid level measurement is to determine whether to submerge or mount the sensor externally.
Venting a gauge reference hydrostatic pressure sensor to the outside air is not always possible and an absolute reference sensor has to be used instead.
Understanding the temperature limitations of a pressure transducer will help you extend the service life and prevent premature failures.
One of the main causes of failure in submersible applications of pressure transducers and transmitters is moisture ingress.
Understand what parameters are included in pressure sensor accuracy specifications and what techniques were used, so that a true comparison can be made.
For most general purpose applications the DIN43650 plug and socket connector is one of the most widely specified for industrial pressure transmitters.
A guide on what to consider when choosing pressure calibration equipment for calibrating pressure transmitters.
When specifying a pressure range for a hydraulic system there maybe a risk of high pressure spikes.
Are your costs running high for outsourcing analogue pressure gauge calibration? Then maybe it is time to invest in your own pressure calibrator.
Look up a word or phrase to find a page with more information on the chosen pressure measurement topic.
What pressure range you select for a pressure measurement application affects the accuracy and the service life of a pressure transducer.
For the best frequency response use a strain gauge pressure transducer that provides a mV output without any amplification.
There are two reference points for measuring a vacuum pressure.