A pressure transmitter is a device that converts pressure into a pneumatic or electric signal for remote control and transmission. What factors should be considered when selecting a pressure transmitter model?
Tips on How to Choose Pressure Transmitters
- Determine the maximum value of the system’s measured pressure first. In general, you should choose a pressure transmitter with a pressure range of 1.5 times the maximum value.
- Most pressure transmitters will produce “drift” after the prolonged high-temperature operation. Because high-temperature pressure transmitters are required before purchase, it is necessary to know the stability of the pressure transmitter. This type of preparation may reduce future use.
- The pressure transmitter’s packaging, particularly its frame, must be more frequently noticed. It is important to consider the future operating environment of the pressure transmitter, the humidity and how the pressure transmitter will be installed when purchasing the transmitter. In addition, there is a large amount of vibration or shock.
Pressure Transmitter Selection Rules
In industrial practice, the most commonly used sensor is a pressure transmitter. It is widely used in various industrial automatic control environments, such as water conservation and hydropower, railway transportation, intelligent buildings, automatic production control, aerospace, military, petrochemical, oil wells, power, ships, machine tools, pipelines, and many others. As the number of pressure transmitter types grows, selecting the exemplary pressure transmitter is challenging.
- Depending on the pressure being measured, the accuracy and range of the measurements may vary.Therefore, it is vital to consider the scope of the pressure being counted to ensure the accuracy and validity of the results.
- Gauge, absolute, and differential pressure are the most common pressure types.Gauge pressure is less than or greater than atmospheric pressure based on the atmosphere; absolute pressure is the total zero pressure as the reference, which is higher than gauge pressure, and differential pressure is the difference between two pressures.
- According to the pressure range measured.Generally, 80% of the measurement range is chosen as the actual measurement pressure.
- According to the medium that was tested.It is classified into dry gas, gas-liquid, highly corrosive liquid, viscous liquid, high-temperature gas-liquid, and other measurement media. The correct selection of media will help extend the transmitter’s life.
- According to the system’s maximum overload.The full excess of the system should be less than the overload protection limit of the transmitter; otherwise, it will shorten the transmitter’s life and possibly damage it. A pressure transmitter’s safe overload pressure is usually twice the full scale.
- As needed, adjust the accuracy level.The transmitter’s measurement error is divided by the accuracy level. Different levels of accuracy correspond to varying levels of fundamental error (expressed as a percentage of full-scale output). The selection is based on the measurement error control requirements and the economical use principle in practical applications.
- Depending on the operating temperature range of the system.The measuring medium’s temperature should be within the transmitter’s operating temperature range. When used at high temperatures, it produces a significant measurement error and shortens the life of the transmitter. Therefore, the temperature will be measured and compensated during the pressure transmitter manufacturing process to ensure that the measurement error caused by temperature is within the range required by the accuracy level. In addition, consider installing a high-temperature pressure transmitter or auxiliary cooling measures such as condensing pipes and radiators in the event of a high temperature.
- The compatibility of the measuring medium and the contact material.The measurement medium can be corrosive in some cases. Therefore, materials compatible with the measurement medium or special processing must be chosen at this time to ensure that the transmitter is not damaged.
- Depending on the power supply and output signal.Pressure transmitters are usually powered by a DC power supply and offer a wide choice of output signals including 4-20mA.DC, 0-5V.DC, 1-5V.DC and 0-10mA.DC, for example, can have a 232 or 485 digital output.
- Depending on the working environment and other circumstances on-site.For example, if there is vibration and electromagnetic interference, the relevant information should be provided when selecting so that appropriate treatment can be taken. Depending on the specific situation, other methods, such as electrical connection, can be considered in the selection process.