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Guide to Ultrasonic Level Transmitters-for Continuous Non Contact Level Measurement of Liquid & Solids.

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What is an Ultrasonic level transmitter?

Ultrasonic Level Transmitters & Ultrasonic Level Sensors are designed to provide accurate and reliable level sensing for difficult to monitor fluids, where contact with media is not desirable from the extremes of sending: ultrapure to corrosive or even dirty where coating or scaling is possible. Ultrasonic level transmitters have no moving parts, are easy to install and simple to use.

Ultrasonic level measurement provides continuous, non-contact and maintenance-free level measurement of fluids, pastes, sludges and powdery to coarse bulk materials. The measurement is unaffected by dielectric constant, density or humidity and also unaffected by build-up due to the self-cleaning effect of the sensors.

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Guide to Ultrasonic Level Transmitters

The basics of ultrasonic level transmitters – how they work and what they’re used for

Ultrasonic Level Transmitters working principle

The Ultrasonic Level Transmitter consists of three parts: ultrasonic transducer (probe), drive circuit (module), and electronic display module.

The Ultrasonic Sensor is installed on the storage tank or process vessel. The sensor sends out a sound wave, which ricochets off the surface of the liquid and returns to the sensor. The time it takes for the sound wave to travel from the sensor to the liquid surface and return to the sensor is measured. This time delay is proportional to the level of the liquid.

The drive circuit processes the signal from the Ultrasonic Sensor, compensates for adverse conditions (temperature, pressure, etc) and converts it into a standard 4-20mA or 0-5/10 Vdc signal that can be read by a PLC, DCS or Display/Transmitter.

The Display/Transmitter converts the 4-20mA or 0-5/10 Vdc signal into a display reading in the unit of measure required (feet, inches, meters, centimeters, etc). Ultrasonic level transmitters can be outfitted with local displays and push button controls for easy configuration without the need of a laptop or other computer.

Applications

Ultrasonic level transmitters are used for inventory management and process automation in a wide range of industries. Applications include:

  • Food & Beverage
  • Water & Waste Water
  • Chemical
  • Petroleum
  • Pharmaceutical

Read more about: Ultrasonic Level Sensor Applications

Featured Ultrasonic level transmitters

ModelIntegrated ModelSplit model
Pictures
Measuring range5m、10m、15m、20m、30m5m、10m、15m、20m、30m
Accuracy0.5%~1.0%0.5%~1.0%
Resolution3mm or 0.1% (choose the bigger)3mm or 0.1% (choose the bigger)
DisplayLCD LCD
Analog output4 wire system 4~20mA/510Q loading
2 wire system 4~20mA/250Q loading		4~20mA/510Q loading
Relay output2 sets of AC 250V/ 8A or DC 30V/ 5A are optional, state is programmable2 sets of single-channel are (optional), the double channel is 4 sets of AC 250V/ 8A or DC 30V/ 5A, the state is programmable
Power supplyStandard: 24VDC 
Optional: 220VAC + 15% 50Hz		Standard: 220V AC + 15% 50Hz
Optional: 24VDC 120m
Customized 12VDC or battery-powered
Environmental temperatureMeter display -20 ~ +60°C 
Probe -20~+80°C		Meter display -20~ +60°C 
Probe-20~+80°C
CommunicationOptional 485,232 communication (manufacturer agreement)Optional 485, 232 communication (manufacturer agreement)
Protection classDisplay meter IP65, Probe Ip68Display meter IP65, Probe Ip68
Probe cableNo100m reachable, standard 10m
Probe installationSelection based on measuring range and probeSelection based on measuring range and probe

Ultrasonic level transmitter data sheet

Ultrasonic-Level-Meters-Catalogue

Extended reading: liquid nitrogen level sensor

The benefits of using an ultrasonic level transmitter

– Ultrasonic level transmitters are easy to install and simple to use.

– Ultrasonic level measurement provides continuous, non-contact and maintenance-free level measurement of fluids, pastes, sludges and powdery to coarse bulk materials.

– Ultrasonic level transmitters are unaffected by dielectric constant, density or humidity and also unaffected by build-up due to the self-cleaning effect of the sensors.

Sino-Inst offers a wide range of Ultrasonic Level Transmitters that can be used in various industries for inventory management and process automation. If you have any questions about which Ultrasonic Level Transmitter is right for your application, please contact us and we will be happy to assist you.

Read more about 7 Level Senors for Tank Level Measurement

How to choose the right ultrasonic level transmitter for your needs

1. The ultrasonic level meter can only be used for the medium that can fully reflect sound waves and propagate sound waves. For the sound wave adsorption ability of the medium, it is not suitable to use ultrasonic level meter.

2. The ultrasonic level meter can not be applied to vacuum occasions, and not for negative pressure occasions. Because the propagation of ultrasonic waves need air medium. And the thin air environment is very unfavorable to ultrasonic propagation. Plus the sound attenuation will therefore increase. Ultimately, it will lead to serious errors in measurement or even can not be measured.

3. If the measured medium is a volatile liquid, or contains a large amount of water vapor, dust, bubbles, suspended particles and other media, the ultrasonic level meter should not be used.
This is due to the fact that when the sound waves from the probe of the ultrasonic level meter encounter the above medium, irregular reflection and scattering will occur. The probe will not be able to receive the normal signal. And these media will absorb the sound waves. This causes the attenuation of sound waves and affects the measurement results.

4. If there are obstacles or equipment that affect the propagation of sound waves inside the vessel. Then the ultrasonic level meter is not recommended.

5. Ultrasonic level meter can generally only be applied in the normal temperature and pressure range. If the pressure is too high, it will have a strong inhibiting effect on the sound speed of the acoustic wave. Eventually, it will affect the measurement accuracy, or even impossible to measure. And the temperature generally cannot exceed 100℃.

Tips for ultrasonic level transmitter installation

Before installing the ultrasonic level Transmitters, please read the instruction manual of the ultrasonic level Transmitters carefully. Work according to the instructions.

At the same time, it should be reconfirmed whether the model of the instrument matches the environmental requirements of the site such as process pressure, process temperature, and chemical properties of the medium. To ensure that the instrument can be used normally after installation.

To install the ultrasonic level meter, please observe the following operating rules:

  1. Try to avoid in-tank facilities such as ladders, heating equipment, limit switch brackets, etc. for installation.
  2. The ultrasonic beam must not intersect the feed stream. At the same time, pay attention to ensure that the highest material level does not enter the measurement blind area during installation. The ultrasonic level Transmitters must not be installed above the feed stream.
  3. When installing the ultrasonic level Transmitters, it should keep a certain distance from the tank wall. And keep the transducer perpendicular to the liquid surface as much as possible.
  4. When installed outdoors, the ultrasonic level Transmitters should take sunshade and rainproof measures. To avoid direct sunlight and reduce measurement errors caused by temperature changes. At the same time should also pay attention to moisture.
  5. The ultrasonic level Transmitters installed in the hazardous area must comply with the installation regulations of the national explosion-proof hazardous area. The intrinsically safe ultrasonic liquid level Transmitter is installed in the occasion with explosion-proof requirements, and the ultrasonic liquid level Transmitter must be grounded.
  6. When there is stirring in the container. The ultrasonic level Transmitters should be kept away from the agitator. In order to eliminate the false echo effect produced by the stirring blade. If foam or waves are created due to agitation, the still-pipe installation method should be used.
  7. When there is foam in the container. When feeding, stirring or doing other processing in the container, foam will be formed on the surface of some media, which will attenuate the signal of the ultrasonic level Transmitter. The sensor should be installed in a still-pipe or a guided-wave radar level Transmitters should be used. Guided wave radar level Transmitters measurements are not affected by foam and are ideal for this application.
  8. When there is airflow in the container. If there is a strong airflow or air vortex in the container, or if it is installed outdoors and in a very windy place. The sensor should be installed in a still-pipe or a guided-wave radar level Transmitters should be used.

Depending on the shape of the tank top of the container, the installation position of the ultrasonic level transmitter should be selected to avoid multiple reflection echoes between the liquid level and the top wall. In order to reduce interference, reduce noise signal and ensure the accuracy of detection.

Installation position of ultrasonic level transmitters

The reasonable installation position of the ultrasonic level transmitter should be determined according to the different top and internal structure shapes of the liquid container:

A. Grooved container:

  1. The support frame should be firm and reliable;
  2. The height of the intersection line of the beam emitted by the probe and the tank wall must be less than or equal to the minimum height of the liquid level to be measured;
  3. The installation height should be within the required range.

B. Arched container:

Meters cannot be installed on vaulted ceilings. It should be installed at 1/2 or 1/3 of the radius of the empowerment.

C. Conical container:

For conical containers with flat tops. The best place to install the meter is in the center of the top of the vessel. This ensures that you measure to the bottom of the container.

ultrasonic level sensor alternative products

Alternative to VEGAPULS 64-80GHz FMCW Level Radar
SIRD-905 Horn Antenna Radar Tank Level Sensor
SIRD-802 Radar Level Sensor for Corrosive Liquids
Pressure Guided Submersible Level Transmitter

SI-U01 Float Level Sensor

Remote Seal Differential Pressure Transmitter
Differential pressure(DP) level transmitter
SI-PCM260 Deep Well Water Level Sensor
SI-151 Hydrostatic Level Sensor
SIRD70 Guided Wave Radar (GWR) Level Transmitters

More Level Measurement Solutions

Frequently
Asked
Questions

Help Center

Ultrasonic level transmitters use sound waves to measure the level of a liquid in a tank. The transmitter sends out a sound wave and measures the time it takes for the sound wave to bounce back. The transmitter then calculates the distance from the sensor to the liquid surface and displays the level on a digital display.

An ultrasonic level sensor is a device that uses sound waves to measure the level of liquids, pastes, sludges, and other similar substances. Ultrasonic sensors are unaffected by dielectric constant, density or humidity, and also have a self-cleaning effect that prevents build-up.

Ultrasonic level measurement works by sending out a sound wave from the sensor and measuring the time it takes for the sound wave to bounce back. The time it takes for the sound wave to bounce back is directly proportional to the level of the liquid. Ultrasonic sensors are very accurate and can be used in a wide range of applications.

Radar level transmitters use microwave energy to measure the level of liquids, while ultrasonic level transmitters use sound waves. Both technologies have their own advantages and disadvantages. Radar is more accurate than ultrasonic, but it is also more expensive. Ultrasonic is less accurate than radar, but it is less expensive and easier to install.

Sino-Ins offers 20 ultrasonic level transmitters products.

About 13% of these are ultrasonic level transducers, 4% are ultrasonic level indicators.

A wide variety of ultrasonic level transmitters options is available to you, such as free samples, paid samples.

Sino-Inst is an ultrasonic level transmitter supplier, located in China.

Ultrasonic level transmitter products are most popular in North America, Mid East, and Eastern Europe.

The United States, and India, which export 99%, 1%, and 1% of ultrasonic level transmitters respectively.

You can ensure product safety by selecting from a certified supplier, with ISO9001, ISO14001 certification.

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How Does a Pressure Transmitter Work?

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What is a pressure transmitter?

A pressure transmitter also often called a pressure transducer. A pressure transmitter is a device used to measure the pressure of liquids or gases in pipes or containers. It works by converting the pressure readings into an electrical signal that can be easily transmitted to a control system for monitoring and analysis.

These devices are commonly used in industrial settings, such as in manufacturing plants and refineries. Where it’s important to monitor the pressure of gases and liquids flowing through pipes and containers to ensure that they’re at safe levels.

Pressure transmitters can measure pressure in gases, liquids, air or oil. Widely used in various industrial processes. Such as pharmaceutical industry, chemical feed, waste water industry, food industry, farms, etc.

Overall, pressure transmitters are essential tools for measuring and monitoring pressure levels in various settings, helping to keep people and equipment safe and functioning properly.

In order to choose a suitable pressure transmitter, we must understand what types of pressure transmitters are there, what are the functions of pressure transmitters, and how do pressure transmitters work? Read on to find out the answers below.

Types of Pressure Transmitters

According to different measurement media, pressure transmitters can be divided into liquid pressure transmitters and gas pressure transmitters.
According to the measurement conditions, the pressure transmitter can have a high temperature type, a very low temperature type, and a high pressure type.
Here we divide by the type of pressure measured.

Type of Pressure TransmitterCharacteristics/Principles
Absolute Pressure Transmitter– Measures pressure relative to atmospheric pressure
– Can only measure positive pressures
Gauge Pressure Transmitter– Measures pressure relative to atmospheric pressure
– Can only measure positive pressures
Differential Pressure Transmitter– Measures the difference between two pressures
– Can measure both positive and negative pressures<br>- Used to measure flow rates
Vacuum Pressure Transmitter– Measures pressure below atmospheric pressure
– Can only measure negative pressures
– Used to maintain vacuum in a process
Hydrostatic pressure transmitters– Often called level transmitters. Because of their working principle and ability to measure level.
– Hydrostatic pressure transmitters work on the basis that the amount of pressure increases with depth.
– These devices are submersible and can be used for liquids and gases.

Featured Pressure Transmitters

SI-503K Gas Pressure Sensor
SI-702 High Pressure Sensor
SI-702S Ultra-High Pressure Senors
SI-512H High Temperature Pressure Sensor
SIJC-1000HSM-Silicon Pressure Sensor
SI-706 Combined Pressure and Temperature Sensor-Dual function
Diffused silicon Gauge Pressure Transmitter
Capacitive Gauge Pressure Transmitter
Explosion-proof Pressure Transmitter
Diaphragm Seal Pressure Transmitter

Pressure Transmitter Working Principle

A pressure transmitter is a device that measures the pressure of fluids or gases in a process and converts it into an electrical signal that can be used for monitoring or control purposes. There are several different working principles that pressure transmitters use to accomplish this:

One of the main components of piezoresistive pressure transmitters is the resistance strain gauge. It is a sensitive device that converts the strain change on the DUT into an electrical signal.

Usually, the strain gauges are closely bonded to the substrate that generates mechanical strain with a special adhesive. When the stress of the substrate changes, the resistance strain gauge also deforms together. Change the resistance value of the strain gauge, so that the voltage applied to the resistance changes. The transmitter has extremely low price and high accuracy and good linearity characteristics.

Diffused silicon pressure transmitters were introduced in the mid-1990s. It utilizes the piezoresistive effect of elastic elements. When the pressure of the measured medium directly acts on the diaphragm of the sensor, the diaphragm produces a micro-displacement proportional to the pressure of the medium, which changes the resistance value of the sensor. This change is detected electronically. And convert and output a unified standard signal.

Compared with traditional products, this transmitter has the advantages of advanced technology, reliable performance, convenient installation, high accuracy and small size.

Corrosion-resistant ceramic pressure transmitters have no liquid transfer. When the pressure acts on the ceramic diaphragm, the diaphragm will produce a slight deformation. Make the thick film resistor printed on the back of the ceramic diaphragm pass through the Wheatstone bridge (closed bridge) connected to it. Output a voltage signal proportional to the excitation voltage.

The pressure physical quantity is measured through the built-in circuit of the transmitter and converted into a unified standard signal.

The transmitter can introduce various media (corrosive and non-corrosive gases, liquids) directly to the ceramic diaphragm.

The thermal stability of the ceramic and its thick-film resistance allow it to operate over a temperature range as high as -40°C to 135°C.

Therefore, it has high measurement accuracy, good stability, strong output signal and low price.

Piezoelectric pressure transmitters work on the piezoelectric effect.

The crystal is anisotropic, and when a force is applied along a certain direction, the crystal can produce an electric effect. When the mechanical force is removed, it will return to the uncharged state again. The piezoelectric materials mainly used in sensors are quartz, sodium potassium tartrate and ammonium dihydrogen phosphate.

The transmitter is mainly used in the measurement of acceleration and pressure. It has the characteristics of simple structure, small size, light weight and long service life. But it can only be used to measure dynamic stress.

The capacitive pressure transmitter is composed of a measuring diaphragm and electrodes on both sides of the insulating sheet to form a capacitance.

When the pressure on both sides is inconsistent, the displacement of the measuring diaphragm is proportional to the pressure difference. Therefore, the capacitance on both sides is not equal.

Through the oscillation and demodulation link, it is converted into a signal proportional to the pressure. Then the pressure physical quantity is measured and converted into a unified standard signal through the transmission circuit.

It has high precision, corrosion resistance, pollution resistance and good stability. It is recognized as an ideal instrument for detecting low vacuum pressure at home and abroad. It is mainly used in various fields of civil industry, and plays a unique role in military industries such as aerospace industry and nuclear industry.

Extended Reading: Smart pressure transmitter

Capacitive pressure transducer

Video source: https://www.youtube.com/embed/QrT8VWxdxwk?rel=0

Read more about: How does a differential pressure transmitter work

Flange Mounted Differential Pressure Transmitter
Extended Diaphragm Seal DP Level Transmitter
Remote Seal Differential Pressure Transmitter
Differential pressure(DP) level transmitter

Pressure transmitter signal output

There are three common signal outputs that pressure transmitters provide: millivolt, amplified voltage, and 4-20mA.

Below is a summary of the outputs and when they are best used.

Millivolt Output:

This type of output signal is a low-level voltage signal that is proportional to the pressure being measured. The signal typically ranges from 0-50mV or 0-100mV, depending on the specific pressure range being measured.

This type of output signal is usually used in applications where the signal needs to be amplified or converted to a different format before it can be used by the control system.

Amplified Voltage Output:

This type of output signal is a higher-level voltage signal that has been amplified to a specific range, such as 0-5V or 0-10V.

The voltage signal is proportional to the pressure being measured and can be used directly by the control system without the need for additional signal conditioning.

Amplified voltage output signals are commonly used in applications where the control system requires a voltage input signal.

4-20mA Output:

This type of output signal is a current signal that ranges from 4mA at zero pressure to 20mA at the maximum pressure being measured.

This type of signal output is popular because it is immune to electrical noise and can be transmitted over long distances without signal degradation.

4-20mA output signals are commonly used in industrial applications where the control system requires a current input signal.

The choice of signal output will depend on the specific requirements of the application, such as the distance between the pressure transmitter and the control system, the required accuracy and resolution, and the environmental conditions.

Extended reading: Pressure indicator transmitters

Read more about: What is industrial pressure transmitter?

How to Choose Pressure Transducer

There are multiple types of pressure transducers for a variety of applications.

Each pressure transducer has different aspects, that will impact how it works and the applications the pressure transducer works best for.

When selecting a pressure transducer, keep these 6 criteria in mind:

  1. Application and measurement type
  2. Pressure range
  3. Process media
  4. Temperature range and installation environment
  5. Accuracy
  6. Output

If you still don’t know how to choose the pressure transmitter, please contact our sales engineers.

how to use a pressure transducer?

Once you receive the pressure transmitter you ordered, you are ready to use it. First, please check the instruction manual configured by the manufacturer. Based on our many years of experience at Sino-Inst, you can start using a pressure transmitter by following these steps:

  1. Confirm parameters: Before use, please confirm whether the model, range, output type (generally 4-20 mA current output or 0-10 V voltage output) and working voltage of the pressure transmitter meet your application requirements.
  2. Check the appearance: Carefully check whether the transmitter is physically damaged and whether the interface is clean.
  3. Installation location: Install the pressure transmitter on the pipe or container that needs to be measured, ensuring that it is installed securely. Usually the pressure interface should be vertical to the ground.
  4. Connect the power supply and output: According to the instructions of the pressure transmitter, connect the power cord and output cord. Current-type transmitters need to be connected in series in the control loop, and voltage-type transmitters need to be connected in parallel on the measuring equipment.
  5. Zero point calibration: Perform zero point calibration in a no-pressure state to ensure that the output of the transmitter is 4 mA or 0 V when there is no load.
  6. Testing and debugging: Turn on the power and gradually increase the pressure. Observe whether the output signal changes linearly with pressure. Adjust settings until the transmitter’s output meets operating requirements.
  7. Record data: Record the output current or voltage value under different pressures. To ensure that the pressure transmitter can accurately reflect pressure changes throughout the entire working range.
  8. Periodic calibration: Check and calibrate the pressure transmitter regularly to ensure its accuracy and stability in long-term operation.

Can a pressure transducer be used to measure volume?

Pressure transducer cannot be used to directly measure volume. Pressure transmitters are used to measure medium pressure.

However, we can also calculate the volume indirectly through measurements from a pressure transmitter. But this requires other parameters.

For example, in a closed tank, if the temperature of the gas can be kept constant. Then measuring the pressure of the gas can be used to calculate the volume of the gas. This is based on Boyle’s law, which states that the pressure of a gas is inversely proportional to its volume.

Or, in some liquid tanks, if the tank is regular, then we can calculate the cross-sectional area of the tank. Then by measuring the pressure at the bottom of the container, we can calculate the volume of the liquid. Our volumetric recorders also enable this conversion.

Our Pressure Transmitter Markets and Applications

Pressure Transducer Price

There are a number of factors, that will impact the price of a pressure transducer.

The biggest differentiator is whether you can use a standard, off-the-shelf pressure transducer or if you need a custom pressure transducer.

For an off-the shelf pressure transducer, pressure transducer prices will be most affected, by the level of accuracy required for your application.

The more accurate, typically the more expensive the pressure transducer.

Extended reading: What is a pressure sensor?

Choose the right pressure transducer for your application

Sino-Inst offers over 20 Pressure Transmitters. A wide variety of  Pressure sensors options are available to you. Such as free samples, paid samples. Sino-Inst is a globally recognized manufacturer of Pressure sensors, located in China.

Sino-Inst sells through a mature distribution network that reaches all 30 countries worldwide. Pressure sensors products are most popular in Europe, Southeast Asia, and Mid East. You can ensure product safety by selecting from certified suppliers. With ISO9001, ISO14001 certification.

Request a Quote

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Pressure Transmitter Calibration

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Pressure transmitter calibration is what you need to do before you install the pressure transmitters. Also called pressure transducer calibration, or pressure sensor calibration.

In this article, we will share pressure transmitter calibration using hart communicator.

Pressure transmitters used in the process industries are very durable and reliable instruments.

Even so, they still require periodic maintenance and calibration to ensure optimal performance.

RFQ Pressure Transmitter

Before we start to calibrate the pressure transmitter, we should know:

What is span in pressure transmitter?


Fig. showing span and zero adjustment

Span value:
The difference between two minimum value and maximum value of readings is known as a span value.

As shown in fig. below span = 20mA – 4mA

Zero Value:
The value of readings at zero lines (Y-axis) is known as zero value as shown in the figure.

How Often Should You Calibrate a Pressure Transmitter?

Pressure transmitters require regular maintenance and calibration to ensure optimum performance.

There are no specific rules for the calibration of pressure transmitters. However, this depends on the regulations the company must comply with and the purpose of the calibration. Examples include safety specifications, application requirements, process conditions or as part of standard maintenance.

General industry practice is to calibrate pressure transmitters every 1 to 3 years based on the above conditions.

If it is found that there are obvious errors, or it is more important, the calibration cycle can be shortened.

Extended reading: Pressure Sensor Applications-Featured Industry Applications

how to calibrate a 4-20mA pressure transmitter

Once you have established the calibration interval and MPE, you are ready to perform the actual calibration procedure on your pressure transmitter.

The best-practice recommendation is:

  1. Mount the transmitter in a stable fixture free from vibration or movement.

  2. Exercise the sensor or membrane before performing the calibration.

    This means applying pressure and raising the level to approximately 90 percent of the maximum range.
    For a 150 psi cell that means pressurizing it to 130–135 psig. Hold this pressure for 30 seconds, and then vent.
    Your overall results will be much better than if you calibrate “cold.” cent of the maximum range.
    For a 150 psi cell that means pressurizing it to 130–135 psig.
    Hold this pressure for 30 seconds, and then vent.
    Your overall results will be much better than if you calibrate “cold.”

  3. Perform a position zero adjustment (zero the transmitter).

    This is important because the orientation of the fixture used for calibration may be different than the way the transmitter is mounted in the process.
    Failing to correct for this by skipping this step can result in nonconformance.
    You may like:
    Magnetostrictive level transmitters
    Magnetostrictive level sensor

  4. Begin the Pressure Transmitter Calibration procedure.

    Typically this means three points up (0 percent/50 percent/100 percent) and then three points down.
    The 4–20 mA output should be 4 mA, 12 mA, and 20 mA at the three points (or the correct digital values for a smart transmitter).
    Each test point should be held and allowed to stabilize before proceeding to the next.
    Normally that should take no more than 30 seconds.
    You can use more points if you require higher confidence in the performance of the instrument.

  5. Compare the results of your pressure transmitter to your reference device.

  6. Document the results for your records.

Pressure transmitter calibration formula

There is a formula that we can easily use to convert most (or all) units utilizing 4 to 20 mA signal to mA units.

There are others out there but this is the simplest I know.

Below is a simple formula for pressure to current conversion. 

For example:

the range is :  0 to 10 Bar

Full range = 10 Bar

Displayed or measured value:  7 Bar

15.2 mA is the equivalent current value of a 7 Bar pressure.

（Read more about: Common Units Of Pressure）

For Value or range which is not starting with zero ( with a vacuum range), use below linear interpolation formula. 

You can also encode this to excel for easier conversion.

If you want to know and calculate the error,

Just subtract the True value with your computed value.

Error = Measured Value – True Value.

If the Pressure Transmitter has an accuracy of 0.5% of the range,

then 0.005 x 7= +/-0.035 Bar,

you can use this as the tolerance to determine a pass or fail result.

Or you can ask the user for their respective tolerances.

Read more about: What Is 0-10V Signal Output?

How to calibrate pressure transmitter with hart communicator

Equipment required for Pressure Transmitter Calibration

Pressure transmitter, multimeter, HART communicator

The basic procedure for Pressure Transmitter Calibration

  1. Isolate the Pressure Transmitter from the Process.
  2. Slowly open the vent plug and the vent valve to release the pressure.
  3. Connect the multimeter with the transmitter and ensure that output is 4ma when 0 pressures are applied.
  4. Connect the handheld test pump (pressure source) to the transmitter.
  5. Ensure there is no leak.
  6. Apply pressure range at 0%, 25%, 50%, 75%, 100% and check there is any error.
  7. If there is any error calibration should be done.

Read more about HART Pressure Transmitter

If the transmitter is the analog transmitter

  1. Apply 0% pressure as per LRV with handheld test pump and check multimeter if it is not 4ma adjust the zero pot in the transmitter and correct transmitter output to 4ma
  2. Apply 100%pressure as per the URV and correct 20ma in multimeter by adjusting span pot in the transmitter
  3. Repeat these steps to rectify the error.

In case of SMART Transmitter

  1. We have to use HART communicator, connect the communicator with the transmitter select the HART Communicator Menu for lower range value trim and upper range value trim.
  2. Basic Set up – Calibration – Zero Trim/Sensor Trim —Lower/Upper range value trims.
  3. HART communicator will automatically calibrate the transmitter.
  4. Restore the process connection
  5. Take the transmitter on line. Ensure there is no leak  

a small example of five-point calibration is given below

Low range value=0psi

upper range value=200psi

This calibration can work for Rosemount 3051 calibration.

Preparing for Field Calibration of Differential Pressure Transmitters

The usual practice is to disassemble the joint of the pressure guiding tube and the differential pressure transmitter, and then connect to the pressure source for calibration. It is troublesome and labor-intensive. The most worry is that there will be leakage or the pressure guiding pipe will be broken when disassembling and assembling the joint.

No matter what type of differential pressure transmitter, the positive and negative pressure chambers have exhaust, drain valves or cocks. This provides convenience for on-site calibration of the differential pressure transmitter, so that it can be calibrated without removing the pressure guiding tube. Differential pressure transmitter.

But make a fitting with the same thread as the vent, drain valve or cock.

When the differential pressure transmitter is calibrated, first close the positive and negative valves of the three-valve group. Open the balance valve, and then loosen the exhaust and drain valves to vent.

Then use a self-made connector to replace the vent, drain valve or cock connected to the positive pressure chamber.
The negative pressure chamber is kept unscrewed, allowing it to vent to the atmosphere.

The pressure source is connected with the self-made joint through the rubber tube. Close the balance valve. And check the air circuit sealing.

Then connect the ammeter (voltmeter) and the hand-operated communicator into the differential pressure transmitter circuit, and start the calibration after power-on and preheating.

Field Calibration of Conventional Differential Pressure Transmitters

First adjust the damping to zero state, first adjust the zero point. Then add full pressure to adjust the full scale, so that the output is 20mA. The adjustment should be fast in the field. Here is a quick adjustment method for zero point and span.

When the zero point is adjusted, it has almost no effect on the full scale, but when the full scale is adjusted, it has an effect on the zero point. When there is no migration, the effect is about 1/5 of the range adjustment amount, that is, the range is adjusted upward by 1mA. The zero point will move upward by about 0.2mA ,vice versa.

E.g:
The input full scale pressure is 100kPa, the reading is 19.900mA.
The range-adjusting potentiometer makes the output 19.900+(20.000-19.900)×1.25=20.025mA, and the range increases by 0.125mA. Then the zero point increases by 1/5×0.125=0.025, and the zero-point potentiometer makes the output 20.000mA.

After the zero point and full scale adjustment are normal, check the middle scales, and make fine adjustments if they are out of tolerance. Then carry out the adjustment work of migration, linearity and damping.

Smart Differential Pressure Transmitter Field Calibration

The intelligent differential pressure transmitter is between the input pressure source and the output 4-20mA signal. In addition to machinery and circuits, there is also a microprocessor chip that operates on the input data.

Therefore, the field calibration method of intelligent differential pressure transmitter is different from that of conventional differential pressure transmitter.

Read more about: Static Pressure Vs Dynamic Pressure Vs Total Pressure

The differential pressure liquid level transmitter has been calibrated according to customer requirements in terms of range, accuracy, linearity and other parameters. And mark the range, accuracy, etc. on the nameplate of the differential pressure liquid level transmitter. As long as the parameters such as the density of the measured medium meet the requirements of the nameplate, there is usually no need to adjust.

If the customer needs to adjust the span or zero position, please adjust according to the following methods. Assuming that the range of the differential pressure liquid level transmitter is 0~10 meters:

  1. Unscrew the back cover of the differential pressure liquid level transmitter, connect an external standard 24VDC power supply and an ammeter (requires an accuracy of 0.2% or higher) to adjust.
  2. When there is no liquid in the differential pressure liquid level transmitter. Adjust the zero point potentiometer so that the output current is 4mA.
  3. Pressurize the differential pressure liquid level transmitter to the full scale (10 meters). Adjust the full-scale resistor so that the output current is 20mA.
  4. Repeat the above steps two or three times until the signal is normal.
  5. Please input 25%, 50% and 75% respectively to check the deviation of the differential pressure liquid level transmitter.
  6. For non-water media, when the differential pressure liquid level transmitter is calibrated with water, it should be converted according to the pressure generated by the actual use of the medium density. For example, when the density of the medium is 1.3, the 1.3m water level should be used to calibrate the 1m range.
  7. After adjustment, tighten the back cover.
  8. The calibration cycle of the differential pressure liquid level transmitter is once a year.
  9. The HART intelligent differential pressure liquid level transmitter of Sino-Inst can be selected, which is convenient to adjust the range of the differential pressure liquid level transmitter.

Learn more about Pressure Transmitter Calibration

When you buy a pressure transmitter, for example, you have the instrument range, which is the pressure range the device can support.

This range covers the overpressure that might occur in the device.

The measuring range covers the values where the transmitter works properly, omitting the overpressure zone.

The lower range limit (LRL) and upper range limit (URL) define this range.

Inside the measuring range, you’ll find the calibration span, the range in which your device will be working, depending on your application.

The calibration span covers the difference between your upper range value (URV), the maximum value your transmitter can read, and the lower range value (LRV), the minimum value the device can read.

So there you go!

You should also know that each instrument has a minimum and maximum calibration span it can support.

If you go below or over these limits, you’ll lose accuracy in your readings.

Make sense? Let me give you an example, just to make it clearer.

Let’s say you want a pressure transmitter with a measurement range of -100 to 200 kilopascals (kPa).

This device can measure pressures as low as -100 and as high as 200 kPa.

If your application just requires pressure between -20 to 50 kpa, then this will be your calibration range.

Your calibration span is the URV-LRV.

By the numbers: 50 – (-20) = 70 kPa.

Therefore, you get a calibration span of 70 kPa, which falls inside the span range (10 to 200 kPa).

A pressure transmitter or pressure sensor is a device that measures pressure in a liquid, fluid, or gas. 

Pressure transmitters are commonly used to measure the pressure inside of industrial machinery, in order to alert the user before a catastrophe occurs.

Extended reading: Pressure Sensor Applications-Featured Industry Applications

Yes, pressure transducers require calibration.
Pressure transducers are used in many applications to provide accurate, real-time data on how systems work. Calibration is critical to maintaining the accuracy of pressure sensors. And it’s not a one-time process.

If the sensor deviates from its specified pressure range, it may cause erroneous pressure readings. This results in degraded device performance and possible security issues.

Calibration allows users to be completely confident that their pressure transducers are performing correctly and accurately measuring the desired pressure range.

If you cannot find an answer to your question in our Pressure Transmitter Calibration you can always contact us and we will be with you shortly.

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Conclusion:

It is normal for the pressure transmitter to have a certain error. But if the error is too large, it needs to be calibrated. There are two types of Pressure Transmitter Calibrations: conventional method and intelligent calibration. no matter where
Kinds of preparations must be done before calibration, and then calibrate and debug through the handheld operator.

There are no mandatory fixed requirements for Pressure Transmitter Calibration. Generally, enterprises can formulate them by themselves. Normally, they can be calibrated once a year. Crucially, the calibration cycle can be shortened.

About how to calibrate the pressure transmitter, and what needs to be paid attention to during the process of Pressure Transmitter Calibration. If you still have questions, please feel free to contact our engineers.

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WZP PT100 Series Assembled Thermal Resistance

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WZP PT100 is an industrial thermal resistance. It is used as a sensor for measuring temperature, and it is used in conjunction with display instruments, recording instruments and electronic regulators.

WZP PT100 industrial thermal resistance is the most commonly used temperature detector in the middle and low temperature areas. The main features are high measurement accuracy and stable performance. Among them, the measurement accuracy of platinum thermal resistance is the highest. It is not only widely used in industrial temperature measurement, but also made into a standard reference instrument.

RFQ

WZP thermal resistance range specification

Thermal resistance

type

Temperature range °C

Graduation

Allowable deviation △t℃

 

WZP platinum resistance

 

 

-200-420

 

Pt 100

Class B

Allow ± (0.30+0.005 ∣t ∣)

Grade A (-200-650°C)

Allow ± (0.15+0.002 ∣t ∣)

WZC copper resistance

 

– 150-100

Cu50

-50-100℃ tolerance

±(0.30+6.0x10-3t)

Note:   ︱ t ︱  is the absolute value of the humidity measured by the hygrometer;

More About WZP PT100

PT100 and RTD are both temperature sensors, but PT100 specifically refers to a type of RTD (Resistance Temperature Detector).

RTD is a type of temperature sensor that works by measuring changes in electrical resistance as temperature changes. PT100 RTDs have a resistance of 100 ohms at 0 degrees Celsius, which makes them a common choice for temperature measurement in industrial and scientific applications.

So, PT100 is just one type of RTD sensor that has a specific resistance value at a specific temperature.

A PT100 temperature sensor is a type of temperature sensor that measures temperature by detecting changes in electrical resistance. Specifically, it is an RTD (Resistance Temperature Detector) that has a resistance of 100 ohms at 0 degrees Celsius.

As the temperature changes, the resistance of the sensor also changes in a predictable way, allowing the sensor to accurately measure the temperature. PT100 sensors are commonly used in industrial and scientific applications where precise temperature measurement is important.

PTC and PT100 are both types of temperature sensors, but they work in different ways.

PTC stands for Positive Temperature Coefficient, and it is a type of thermistor that increases in resistance as temperature increases. In other words, the resistance of a PTC sensor goes up as the temperature it is measuring goes up. PTC sensors are commonly used in applications such as over-temperature protection in electronic circuits.

PT100, on the other hand, is a type of RTD (Resistance Temperature Detector) that has a specific resistance value of 100 ohms at 0 degrees Celsius. As temperature changes, the resistance of a PT100 sensor changes in a predictable way, allowing it to accurately measure temperature. PT100 sensors are commonly used in industrial and scientific applications where precise temperature measurement is important.

So, the main difference between PTC and PT100 is that PTC sensors increase in resistance as temperature increases. While PT100 sensors have a specific resistance value at a specific temperature and change resistance in a predictable way as temperature changes.

Calibrating a PT100 temperature sensor involves comparing its readings to known, accurate temperatures and making adjustments to the sensor’s output to ensure it is reading accurately.

Here are the basic steps for calibrating a PT100 sensor:

  1. Obtain a reference thermometer or other temperature calibration device with a known, accurate temperature reading.
  2. Place the reference thermometer and the PT100 sensor in a controlled environment with a stable temperature.
  3. Wait for the temperature to stabilize and record the readings from both the reference thermometer and the PT100 sensor.
  4. Compare the readings and calculate the difference between the two.
  5. Adjust the output of the PT100 sensor as needed to match the reference thermometer reading.
  6. Repeat the process at several different temperatures to ensure accuracy across a range of temperatures.

It’s important to note that calibrating a PT100 sensor can be a complex and technical process. And it may be best to consult with a professional or use specialized calibration equipment to ensure accurate results.

Here are some key differences between RTD temperature sensors and thermocouples:

RTD Temperature SensorsThermocouples
Higher accuracy and repeatability;
Smaller temperature range;
Less susceptible to EMI;
More stable over time and exhibit less drift;
Require a stable, regulated power source to operate;
Can be more expensive;		Wider temperature range;
Can operate in harsher environments;
Do not require a power source to operate;
Can be less expensive;
More susceptible to EMI;
Can exhibit more drift and require frequent calibration;

Read more about: RTD Working Principle & Thermocouple Working Principle

Order Guide

W

Z

Spec

Content

 

 

P

 

Pt resistance

C

 

Cu resistance

 

 

 

 

 

 

 

 

Thermal resistance material

 

 

 

 

 

 

 

 

 

–

1

 

Without fixed device

2

 

Fixed threaded

3

 

Movable flange

4

 

Fixed flange

5

 

Loose coupling type

6

 

Fixed thread conical

7

 

Direct coupling type

8

 

Fixed threaded pipe joint type

9

 

Movable threaded pipe joint type

 

 

 

Fixed installation form

2

 

Splash proof

3

 

Waterproof type

4

 

Explosive–proof type

 

Junction box form

0

Φ16mm protection tube

1

Φ12mm protection tube

Protection tube diameter

No unified design：All kinds of protection tube

W

Z

P

 

–

3

3

0

1

More temperature measurements and applications

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Industrial thermal resistance has the characteristics of high sensitivity and good stability and is widely used. If equipped with corrosion protection tube. Can also be used in corrosive media.

We produce two types of assembled thermal industrial thermometers: WZP PT100 and Pt 10 platinum thermal resistances that meet the professional standard JB/T8622- 1997 (equivalent to the International Electrotechnical Commission IEC751-83 standard) and Cu50 and Cu100 that meet the professional standard JB/T8623- 1997 Copper thermal resistance.

If you need WZP PT100 Series Assembled Thermal Resistance, Please feel free to contact our sales engineers.

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