7 factors that influence the accuracy of your pressure transmitters
7 factors that influence the accuracy of your pressure transmitters
Whatever your industry, greater pressure measurement accuracy means better end product quality, safety and increased production line efficiency.
What are the 7 factors that influence the accuracy of your pressure transmitters ?
The accuracy of measuring instruments such as pressure transmitters degrades over time. Thus, the zero point of the transmitter drifts over the months, which affects the accuracy of the pressure measurement. To compensate for this, pressure measuring devices can be calibrated on a regular basis by using a measuring device calibration company. Fuji Electric's pressure transmitters offer an excellent long-term stability of ±0.1% over a period of 5 years, which guarantees an accurate measurement over time and allows you to extend your calibration intervals and reduce your maintenance costs.
Fuji Electric's pressure transmitters are compensated to avoid the influence of these factors and achieve reliable and accurate measurements without degradation.
In this article we explain the seven factors that influence the accuracy of pressure transmitters.
The surrounding temperature and the fluid temperature
Surrounding temperature and fluid temperature are two factors that influence the accuracy of a pressure transmitter. Each transmitter has temperature tolerances. The temperature range leads to variations in the accuracy of the transmitter. The more extreme the ambient or process temperature, the less accurate the transmitter. When choosing your pressure transmitter, it is important to check that the temperature ranges of the pressure transmitter are suitable for your application.
Some pressure transmitters are temperature-compensated at the time of manufacture over a specific temperature range to avoid temperature variations that could have a negative influence on accuracy. When choosing your supplier, look for an instrument with a temperature compensation function.
Fuji Electric's pressure transmitters are equipped with the unique 4D Gyration™ technology, which ensures accurate measurements regardless of variations in ambient temperature and static pressure.
Static pressure
What is static pressure?
The differential pressure transmitter measures the pressure difference between two measuring points in comparison to the relative pressure transmitter (which measures in comparison to atmospheric pressure) or absolute pressure transmitter (which measures in comparison to void).
Static pressure, also called line pressure, is the pressure in a pipe or process. This process pressure applies to both pressure taps of the differential transmitter.
Influence of static pressure
When both pressure taps of the differential pressure transmitter are at atmospheric pressure then the pressure measured by the transmitter is zero. If an identical higher pressure is applied to both inputs in the same way, the measured pressure is also zero in theory. In practice, the static pressure influences the accuracy of differential pressure transmitters.
Line pressure negatively affects the accuracy and repeatability of the measurement. Static pressure can have an effect on the transmitter zero and span. Field calibration can help eliminate the effects of static pressure in the process.
Fuji Electric'spressure transmitters differential sensors are static pressure-compensated at the time of manufacture to avoid errors that could render the sensor inaccurate. When choosing your supplier, look for a device with a static pressure compensation function.
Static pressure must be taken into account when choosing a differential pressure transmitter. These have a maximum permissible static pressure which must not be exceeded.
Changing the scale of pressure measurement
The accuracy of the measurement varies depending on the measurement scale set on the transmitter.
The scaling dynamics of the pressure transmitter defines the minimum adjustable measuring range in relation to the total pressure scale of the transmitter. This rangeability ratio is a decisive factor when selecting a pressure transmitter.
If the set scale is outside the dynamic range, the accuracy of the measurement is degraded.
Fuji Electric's pressure transmitters have a high dynamic range of 1:100 which allows low pressure scales to be set without affecting the accuracy of the measurement. It is recommended to choose pressure transmitters with a full scale range as close as possible to the actual pressure to be measured.
Long-term stability
The accuracy of measuring instruments, such as pressure transmitters, deteriorates over time. As a result, the zero point of the sensor drifts over the months, affecting the accuracy of the pressure measurement. To compensate for this, these pressure measurement devices can be calibrated on a regular basis by a measurement device calibration company. Fuji Electric's pressure transmitters offer excellent long-term stability of ±0.1% over a 5-year period. This guarantees accurate measurement over time, enabling you to extend calibration intervals and reduce maintenance costs.
The mounting position of the pressure sensor
The mounting position has an influence on the zero point of the pressure transmitter. Even if the pressure transmitters are calibrated at the factory, a shift in the measurement due to the mounting position can be observed on site after installation. This can make the pressure measurement inaccurate. This effect is caused by the weight of the oil filling the measuring cell.
For diaphragm seals pressure transmitters, this effect may be more pronounced due to the larger volume of oil in the transmitter. There is no effect of the mounting position on the scale range.
Field calibration is imperative to eliminate any zero offset caused by the effect of mounting position. To carry out this adjustment, pressure transmitters usually features an adjusting screw and a manifold.
The measuring cells of pressure transmitters can be disturbed by vibrations on industrial equipment. Vibrations have an effect on the accuracy of the measurement. In some cases, it can lead to damage to the transmitter or a shortened service life.
Fuji Electric pressure transmitters have been tested by independent laboratories at very high vibration levels to verify their accuracy and robustness. It is worth asking your transmitter manufacturer for the test results to ensure the vibration resistance of your installations.
The supply voltage of the pressure transmitter
Pressure sensors are supplied with 24 V DC. However, they can generally be operated over a wider voltage range. Incorrect or fluctuating voltage can influence the measurement or even destroy the transmitter in the event of an overvoltage.
It is recommended to use an isolated, stabilised and regulated power supply to avoid inaccuracy of measurement. Fuji Electric pressure transmitters have a wide power supply range from 10.5 V DC to 45 V DC to ensure minimal influence of the supply voltage on the measurement accuracy.
Don't let your next pressure transmitter be influenced
When choosing your pressure transmitter supplier:
Demand accurate measurement in any environment.
Demand a wide 1:100 measurement dynamic range from 1 mbar to 500 bar.
Demand high long-term stability.
Demand on-site commissioning and calibration services.
Demand pressure transmitters that can withstand the most intense vibrations.
Demand a wide power range for your transmitters.
Factor type
Impact on Accuracy
Recommendations for minimizing the effect
Ambient and process temperature
Temperature variations can cause significant measurement errors.
Use pressure transmitters with temperature compensation to minimize these variations.
Static pressure
Negatively affects the accuracy and repeatability of pressure transmitters differential.
Choose pressure transmitters with static pressure compensation and perform on-site calibration.
Change of measurement scale
Incorrect setting of the scale can degrade measurement accuracy.
Choose a suitable measurement scale and use pressure transmitters with a high dynamic range of 1:100.
Long-term stability
Zero drift over time can affect measurement accuracy.
Plan regular calibrations to maintain the long-term accuracy of your pressure transmitters. Choose pressure transmitters with high long-term stability.
Mounting position
The position can modify the sensor zero point, making the measurement inaccurate.
Install pressure transmitters according to the manufacturer's datasheet and check the zero after installation.
Vibrations
Can affect measurement stability and shorten sensor life.
Use anti-vibration mounts to minimize impact. Use vibration-resistant pressure transmitters
Supply voltage
Voltage variations may alter measurements or damage the sensor.
Prefer sensors with a wide power supply range for better tolerance.
Precision factors for pressure transmitters and recommendations
By choosing Fuji Electric pressure transmitter FCX, you can ensure the accuracy of your pressure measurements on your industrial processes. Your plants and facilities operate more safely and efficiently, producing higher quality products and reducing downtime. You can rely on reliability and robustness of Fuji Electric's pressure transmitters to deliver accurate, repeatable measurement.
For optimum measurement accuracy, our technicians offer commissioning of your pressure transmitters . You can be sure that your devices are ready for use and that your installations start up under the best conditions.
Contact us today to find out about all the advantages our sensors have to offer!
