Pressure Sensors – The Widely Used Sense of the Heart

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How to choose the right ceramic core pressure sensor

When choosing a ceramic core pressure transmitter correctly, you should pay attention to the following points: 1. What kind of pressure should be measured by the pressure transmitter 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 fact that in many systems, the maximum value of the measured pressure in the system is determined first. In particular, in the process of water pressure measurement and processing, there are peaks and continue to fluctuate up and down irregularly, and this instantaneous peak can destroy the pressure sensor. Continued high pressure values or slightly exceeding the transmitter's calibrated maximum will shorten the life of the sensor, and in doing so, will also reduce accuracy. A shock absorber can then be used to reduce the pressure burr, 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. 2. What kind of pressure medium solvent or corrosive substance will not destroy the data in the transmitter that is in direct contact with these media. These factors will determine whether to choose a direct separator film and information that is in direct contact with the medium. Viscous liquids and mud will block the pressure interface. 3. How much accuracy does the pressure transmitter need to be nonlinear, and there are those who determine the accuracy. Hysteresis, non-repeatability, temperature, zero bias scale, influence of temperature. But it is mainly caused by nonlinearity, hysteresis, non-repeatability, and the higher the accuracy, the higher the price. 4. the temperature range of the pressure transmitter One of the temperature ranges is the normal working temperature, usually a transmitter will calibrate two temperature sections. The other is the temperature compensation range, the normal operating temperature range refers to the temperature range of the transmitter when it is not damaged in the working state, and the performance indicators of its application may not be reached when the temperature compensation range is exceeded. 5. the pressure transmitter needs to adhere to the stability after overtime This kind of advance work can reduce all kinds of troubles that will occur in future use. Most transmitters will "drift" after overwork, so it is important to understand the stability of the transmitter before purchasing. 6. the packaging of the pressure transmitter is often easy to ignore the packaging of the rack and the transmitter. However, this will gradually reveal its disadvantages in future use. When purchasing a transmitter, it is necessary to consider the working environment of the transmitter in the future, what the humidity is, how to install the transmitter, whether there will be strong impact or vibration, etc. 7. What kind of connection is used between the pressure t

Precautions for working with pressure transmitters

First of all, let's understand the structure and function of conventional pressure transmitters. The pressure transmitter is mainly composed of three parts: a pressure sensor, a measurement conversion circuit and a process connection component. Its function is to convert the physical pressure parameters such as gas and liquid felt by the pressure sensor into standard electrical signals, and supply them to display alarms, DCS systems, recorders, PLC systems, etc. for display, measurement, control and adjustment. In these jobs, many different problems may occur, and at this time, it is necessary to pay attention to the maintenance and protection of the pressure transmitter in the work. Let's take a look at the precautions for specific pressure transmitters in use. 1.First of all, check whether there is signal interference around the pressure transmitter, and if so, try to eliminate it, or connect the sensor shield wire with the metal shell as much as possible to enhance the anti-interference ability. 2.The mounting holes should be cleaned regularly to ensure that the mounting holes are clean. Prevent the transmitter from coming into contact with corrosive or overheated media; 3.When wiring, pass the cable through the waterproof connector (accessory) or winding pipe and tighten the sealing nut tightly to prevent rainwater from leaking into the transmitter housing through the cable. 4.When measuring gas pressure, the pressure take-off should be open at the top of the process pipe, and the transmitter should also be installed in the upper part of the process pipe so that the accumulated liquid can be easily injected into the process pipe. 5.When measuring liquid pressure, the pressure tap should be opened on the side of the process pipe to avoid sedimentation. 6.Voltages higher than 36V should not be used on the pressure transmitter, which can easily lead to damage. 7.In the event of freezing in winter, the transmitter installed outdoors must take anti-freezing measures to prevent the liquid in the impulse port from expanding due to the freezing volume and causing damage to the sensor. 8.When measuring steam or other high-temperature media, it is necessary to connect a condenser such as a buffer tube (coil), and the operating temperature of the transmitter should not exceed the limit. In addition, the buffer tube needs to be filled with an appropriate amount of water to prevent the superheated steam from coming into contact with the transmitter. And the buffer heat pipe must not leak air. Example of a pressure transmitter installation for measuring steam pipes 9.When measuring liquid pressure, the installation position of the transmitter should avoid the impact of the liquid (water hammer phenomenon) to avoid damage to the sensor due to overpressure. 10.The impulse pipe should be installed in a place with small temperature fluctuations; 11.Prevents the debris from being deposited in the catheter; 12.The medium measured by the pre

Dynamic characteristics of water pressure sensors

The static characteristics of a sensor refer to the correlation between the output and input of the sensor for the static input signal. Since the input quantity and the output quantity are independent of time, the relationship between them, i.e., the static characteristics of the sensor, can be described by an algebraic equation without time variables, or by drawing a characteristic curve with the input quantity as the abscissa and the corresponding output quantity as the ordinate. The main parameters that characterize the static characteristics of the sensor are: linearity, sensitivity, hysteresis, repeatability, drift, etc. (1)Linearity: refers to the degree to which the actual relationship curve between the output and input of the sensor deviates from the fitting straight line. Defined as the ratio of the maximum deviation between the actual characteristic curve and the fitted line over the full scale range to the full-scale output. (2)Sensitivity: Sensitivity is an important indicator of the static characteristics of a sensor. It is defined as the ratio of the increment of the output to the corresponding increment of the input that caused the increment. S is used to indicate sensitivity. (3)Hysteresis: The phenomenon that the input and output characteristic curves of the sensor do not coincide during the change of input quantity from small to large (positive stroke) and input quantity from large to small (reverse stroke). For input signals of the same size, the output signals of the forward and reverse strokes of the sensor are not equal, and this difference is called the hysteresis difference. (4)Repeatability: Repeatability refers to the degree to which the characteristic curves obtained by the sensor are inconsistent when the input quantity changes the full scale several times in the same direction. (5)Drift: The drift of the sensor refers to the change of the output of the sensor with time under the condition that the input amount remains unchanged, and the secondary phenomenon is called drift. There are two reasons for drift: one is the structural parameters of the sensor itself; The second is the surrounding environment (such as temperature, humidity, etc.).