Considerations for selecting pressure transmitters

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This post was last edited by shrien on 2015-9-19 20:38. Among various types of instruments, transmitters are the most widely used and common; they are generally divided into pressure transmitters and differential pressure transmitters. Transmitters are commonly used to measure pressure, differential pressure, vacuum, liquid level, etc. Transmitters come in two-wire (current signal) and three-wire (voltage signal) types, with two-wire (current signal) transmitters being particularly common ； There are intelligent and non-intelligent types, with an increasing number of intelligent transmitters ； There are pneumatic and electric types, with electric transmitters being more common ； Additionally, they are divided into intrinsically safe and flameproof types depending on the application ； When making a selection, you should choose accordingly based on your own needs. I. Compatibility of the medium under test: When selecting a product, it is necessary to take into account how the medium affects the pressure interfaces and sensitive components. The material of these pressure interfaces and sensitive components must be considered carefully; otherwise, the outer diaphragm will be corroded after a short period of use, and this corrosion can lead to equipment failures as well as safety incidents involving people. Therefore, the choice of material is extremely important. II. The impact of medium temperature and ambient temperature on the product: When selecting a product, it is necessary to take into account the temperature of the medium being measured as well as the ambient temperature. If these temperatures are higher than the product’s built-in temperature compensation capabilities, it can lead to drift in the measurement data. It is essential to consider the actual operating environment of the transmitter when making a choice, in order to prevent temperature from causing inaccurate measurements due to effects on the pressure-sensitive core. III. Selection of pressure range: When selecting, the operating pressure rating of the equipment must be taken into consideration; the pressure rating of the transmitter must be suitable for the application scenario. IV. Selection of pressure interfaces: During the selection process, it is necessary to strictly adhere to the dimensions of the pressure interfaces used by the customer, choose the appropriate thread connection type, and confirm this through product layout diagrams; alternatively, samples provided by the manufacturer can also be used ； V. Selection of electrical interfaces: When making the selection, it is necessary to carefully verify the user’s signal acquisition method as well as the wiring conditions on site; the sensor signals must be connected to the user’s acquisition interface ； Appropriate and correct electrical interfaces as well as signal methods should be selected. VI. Type selection of pressure: Instruments used to measure absolute pressure are called gauge pressure meters. Ordinary industrial pressure gauges measure gauge pressure, which is the difference between absolute pressure and atmospheric pressure. When the absolute pressure is greater than the atmospheric pressure, the gauge pressure measured is positive, and it is referred to as positive gauge pressure ； When the absolute pressure is lower than the atmospheric pressure, the gauge pressure measured is negative; this is known as negative gauge pressure, or vacuum level. A device used to measure vacuum level is called a vacuum gauge.