1. What kind of pressure should industrial pressure transmitters measure: First, determine the maximum value of the measured pressure in the system. Generally speaking, it is necessary to choose a transmitter with a pressure range that is about 1.5 times larger than the maximum value. This is mainly due to the presence of peak values and continuous irregular fluctuations in many systems, especially in water pressure measurement and processing. These momentary peaks can damage pressure sensors, and sustained high pressure values or slightly exceeding the transmitter's calibrated maximum value can shorten the sensor's lifespan. However, doing so will result in a decrease in accuracy. So, a buffer can be used to reduce pressure spikes, but this will slow down the response speed of the sensor. So when choosing a transmitter, it is important to fully consider the pressure range, accuracy, and stability.
2. What kind of pressure medium: We need to consider the medium measured by the pressure transmitter. Viscous liquids and mud may block the pressure interface, and solvents or corrosive substances may damage the materials in direct contact with these media in the transmission. The above factors will determine whether to choose direct isolation membranes and materials that come into direct contact with the medium. The material of the contact medium part of a typical pressure transmitter is 316 stainless steel. If your medium is not corrosive to 316 stainless steel, then basically all pressure transmitters are suitable for measuring the pressure of the medium If your medium is corrosive to 316 stainless steel, then we need to use chemical sealing. This not only measures the pressure of the medium, but also effectively prevents contact between the medium and the liquid receiving part of the pressure transmitter, thereby protecting the pressure transmitter and extending its life
3. What level of accuracy is required for industrial pressure transmitters? The factors that determine accuracy include nonlinearity, hysteresis, non repeatability in the electromechanical business network, temperature, zero offset scale, and temperature effects. But mainly due to nonlinearity, hysteresis, non repeatability, the higher the accuracy, the higher the price. Every electronic measuring instrument will have accuracy errors, but due to different accuracy levels in different countries, such as China and the United States, the accuracy of the standard is the part with better sensor linearity, which is usually between 10% and 90% of the measurement range; And the accuracy of European standards is the part with the worst linearity, which is commonly referred to as the accuracy between 0 to 10% and 90% to 100% of the measurement If the accuracy of the European standard is 1%, then the accuracy of the Chinese standard is 0.5%
4. What kind of output signal is needed: mV, V, mA and frequency output digital output. The choice of output depends on various factors, including the distance between the transmitter and the system controller or display, whether there is "noise" or other electronic interference signals. Do you need an amplifier, its location, etc. For many OEM devices with short distances between transmitters and controllers, using a transmitter with mA output is the most economical and effective solution. If the output signal needs to be amplified, it is best to use a transmitter with built-in amplification. For long-distance transmission or strong electronic interference signals, mA output or frequency output is used. If in an environment with high RFI or EMI indicators, in addition to choosing mA or frequency output, special protection or filters should also be considered. (Currently, due to various collection needs, there are many types of output signals for pressure transmitters on the market, mainly including 4... 20mA, 0... 20mA, 0... 10V, 0... 5V, etc., but the more commonly used are 4... 20mA and 0... 10V. Among the output signals I mentioned above, only 4... 20mA is a two-wire system, and the output we are referring to is a few wire system without grounding or shielding wires. The others are all three wire systems.)
5. What excitation voltage to choose: The type of output signal determines what excitation voltage to choose. Many amplification transmitters have built-in voltage regulation devices, so their power supply voltage range is relatively large. Some transmitters are quantitatively configured and require a stable operating voltage. Therefore, the available operating voltage determines whether to use a sensor with a regulator. When selecting a transmitter, the operating voltage and system cost should be considered comprehensively.
6. Is it necessary to have interchangeable transmitters: Determine whether the required transmitters can adapt to multiple usage systems. Generally speaking, this is very important. Especially for OEM products. Once the product is delivered to the customer, the cost for calibration is quite high. If the product has good interchangeability, even changing the transmitter used will not affect the overall performance of the system.
7. Stability needs to be maintained after transmitter timeout: Most transmitters will experience "drift" after timeout, so it is necessary to understand the stability of the transmitter before purchasing. This pre work can reduce various troubles that may occur in future use.
8. The packaging of the transmitter: The packaging of the transmitter, especially its rack, is often overlooked, but this will gradually expose its shortcomings in future use. When choosing a transmitter, it is important to consider the future working environment, humidity, installation methods, and whether there will be strong impacts or vibrations.