It is very important for users to choose a suitable and practical capacitive pressure transmitter, so that the problems in future use will be relatively small, so what kind of selection method can be used for reference? Today, we will introduce the selection method of capacitive pressure transmitter in detail.
What kind of pressure the transmitter needs to measure
first determine the maximum value of the measured pressure in the system. Generally speaking, it is necessary to select a transmitter with a pressure range that is about 1.5 times larger than the maximum value. . This is mainly in many systems, especially in water pressure measurement and processing, there are peaks and continuous irregular up and down fluctuations, such sudden peaks can damage the pressure sensor, continuous high pressure values or slightly exceed the transmitter’s Calibrating the maximum value will shorten the life of the sensor, however, because doing so will reduce the accuracy. So, a snubber can be used to reduce the pressure glitch, but this will reduce the response speed of the sensor. Therefore, when selecting a transmitter, it is necessary to fully consider the pressure range, accuracy and stability.
What kind of pressure medium
what we need to think about is the medium measured by the capacitive pressure transmitter. Viscous liquid and mud will block the pressure interface. Will solvents or corrosive substances damage the transmitter? Materials in direct contact with these media. The above factors will determine whether the direct barrier film and the material directly in contact with the medium can be selected. The touch medium of the usual capacitive pressure transmitter is made of 318 stainless steel. If your medium is not corrosive to 318 stainless steel, then basically all capacitive pressure transmitters are suitable for your measurement of medium pressure. .If your medium is corrosive to 318 stainless steel, then we must use chemical sealing, which can not only measure the pressure of the medium, but also effectively prevent the contact between the medium and the capacitive pressure transmitter. Then it plays a role in maintaining the capacitive pressure transmitter, extending the life of the capacitive pressure transmitter.
How much accuracy does the transmitter need
the accuracy is determined by nonlinearity, hysteresis, non-repeatability of electromechanical business network, temperature, zero offset scale, and the influence of temperature. But mainly by nonlinear, hysteresis, non-repeatability, the higher the precision, the higher the price. Every electronic measuring meter will have accuracy errors, but because the accuracy levels marked by different countries are different, for example, the accuracy of national standards such as China and the United States is some of the best linearity of the sensor, that is, we usually The accuracy of the said measurement scale is between 12% and 92%; while the accuracy of the European standard is the worst in linearity, which is 0 to 10% and 90% to 100% of what we usually call the measurement. precision between.
The temperature scale of the transmitter
Usually a transmitter will calibrate two temperature scales, that is, the temperature scale for normal operation and the scale for which the temperature can be compensated. The normal operating temperature range refers to the temperature range when the transmitter is not damaged under operating conditions. When the temperature compensation range is exceeded, the performance target of its use may not be achieved. The temperature compensation scale is a typical scale smaller than the operating temperature scale. Operating at this scale, the transmitter is sure to hit its performance targets. The temperature change affects its output from two aspects, one is the zero drift; the other is the full-scale output.
What kind of output signal is required
mV, V, mA and frequency output digital output, the choice of output depends on many factors, including the distance between the transmitter and the system controller or display, whether there is noise or other Electronic interference signal. Whether an amplifier is required, the position of the amplifier, etc. For many OEM devices where the distance between the transmitter and the controller is short, a transmitter with mA output is the most economical and useful solution. If the output signal needs to be expanded, it is best to choose a transmitter with built-in expansion. Regarding the long-distance transmission or the existence of strong electronic interference signals, the best choice is mA level output or frequency output. If you are in an environment with high RFI or EMI targets, in addition to paying attention to the choice of mA or frequency output, you must also consider special maintenance or filters.
What kind of excitation voltage to choose
the type of output signal determines what kind of excitation voltage to choose. Many expansion transmitters have built-in voltage conditioning equipment, so their supply voltage scale is large. Some transmitters are quantitative devices that require a stable operating voltage. Therefore, the available operating voltage determines whether a sensor with a conditioner can be used. When selecting a transmitter, the operating voltage and system cost should be considered comprehensively.
The stability of the capacitive pressure transmitter needs to be maintained after overtime operation
some transmitters will drift after overtime operation, so it is necessary to know the stability of the transmitter before purchasing. This kind of pre-operation can reduce future All kinds of troubles that will appear in use.
Encapsulation of the transmitter
The encapsulation of the transmitter, especially its frame, is often simply overlooked, but this will gradually expose its defects in future applications. When purchasing a transmitter, you must consider the operating environment of the transmitter in the future, what the humidity is, how to install the transmitter, and whether there will be violent impact or oscillation.
The selection method of capacitive pressure transmitter has been introduced. Now everyone knows the selection knowledge of capacitive pressure transmitter, which is of great help to users. When choosing capacitive pressure transmitter in the future Select to the applicable capacitive pressure transmitter.
