Cheap products

Are cheap products sure to be good? Many people have doubts about this, but please rest assured that we have a large production center, the whole process can be supervised by users, and video inspection can be carried out at any time.

But how to choose a pressure transmitter?

1. Depending on the type of pressure to be measured

Pressure types mainly include gauge pressure, absolute pressure, differential pressure, etc. Gauge pressure refers to the pressure that is less than or greater than atmospheric pressure based on atmosphere; Absolute pressure refers to the absolute pressure zero position as the benchmark, which is higher than the absolute pressure; Differential pressure is the difference between two pressures.

2. According to the measured pressure range

Generally, the actual measuring pressure is 80% of the measuring range.

The maximum pressure of the system shall be considered. Generally speaking, the maximum pressure range of the pressure transmitter should reach 1.5 times of the maximum pressure value of the system. Some hydraulic and process controls have pressure spikes or continuous pulses. These spikes may reach 5 or even 10 times the "maximum" pressure, which may cause damage to the transmitter. Continuous high pressure pulse, approaching or exceeding the maximum rated pressure of the transmitter, will shorten the practical life of the transmitter. However, increasing the rated pressure of the transmitter will sacrifice the resolution of the transmitter. Buffers can be used in the system to reduce spikes, which can slow down the response of the sensor.

The pressure transmitter is generally designed to withstand the maximum pressure in 200 million cycles without reducing performance. When selecting a transmitter, you can find a compromise solution between system performance and transmitter life.

3. According to the measured medium

According to different measuring media, it can be divided into dry gas, gas liquid, strongly corrosive liquid, viscous liquid, high-temperature gas liquid, etc. Proper selection according to different media is conducive to extending the service life of the transmitter.

4. According to the maximum overload of the system

The maximum overload of the system shall be less than the overload protection limit of the transmitter, otherwise the service life of the transmitter will be affected and even the transmitter will be damaged. Generally, the safe overload pressure of the pressure transmitter is twice the full range.

5. Accuracy class as required

The measurement error of the transmitter is divided according to the accuracy level, and different accuracies correspond to different basic error limits (expressed as a percentage of full range output). In practical application, it is selected according to the control requirements of measurement error and the principle of economic use.

6. According to the operating temperature range of the system

The temperature of the measuring medium shall be within the working temperature range of the transmitter. If it is used over temperature, it will cause large measurement error and affect the service life of the transmitter; During the production of the pressure transmitter, the temperature influence will be measured and compensated to ensure that the measurement error caused by the temperature influence is within the range required by the accuracy class. In the case of high temperature, high temperature pressure transmitter can be selected or auxiliary cooling measures such as installing condenser pipe and radiator can be taken.

7. According to the compatibility of measuring medium and contact material

In some measuring occasions, the measuring medium is corrosive, so it is necessary to select materials compatible with the measuring medium or carry out special process treatment to ensure that the transmitter is not damaged.

8. According to the type of pressure interface

Usually threaded (M20 × 1.5) Standard interface.

9. According to the power supply and output signal

Generally, the pressure transmitter is powered by DC power supply, providing a variety of output signal options, including 4~20mA. DC 0 ～ 5V.DC, 1 ～ 5V.DC, 0 ～ 10mA.DC, etc. can have 232 or 485 digital outputs.

10. According to the on-site working environment and others

Whether there is vibration and electromagnetic interference, relevant information shall be provided during model selection for corresponding treatment. When selecting the model, other electrical connection methods can also be considered according to the specific situation.