What are the common faults of the SMC pressure sensor? What is the troubleshooting method?
What are the common faults of the SMC pressure sensor? What is the troubleshooting method? SMC pressure sensor common faults and troubleshooting methods:
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Pressure sensor prone to failure are the following:
The first is the pressure up, and the transmitter loses. In this case, check whether the pressure interface is leaking or blocked. If it is not, check the wiring mode and check the power supply. If the power supply is normal, simply pressurize to see if the output changes, or if the sensor zero point is output. If there is no change, the sensor is damaged, which may be the damage of the instrument or other problems in the whole system;
The second is the pressure transmitter output does not change, and then pressurize the transmitter output suddenly changes, the pressure transmitter zero can not go back, most likely the pressure sensor seal problem. Commonly due to the sealing ring specification, after the sensor is tightened, the sealing ring is compressed to the inside of the sensor pressure inlet to block the sensor. When the pressure is applied, the pressure medium cannot enter, but when the pressure is high, the sealing ring is suddenly opened and the pressure sensor is under pressure. Variety. The best way to eliminate this kind of failure is to remove the sensor and see if the zero position is normal. If the zero position is normal, replace the seal and try again.
The third is the transmitter output signal instability. This failure may be a source of stress. The pressure source itself is an unstable pressure. It is very likely that the instrument or pressure sensor is not strong in anti-interference ability, the sensor itself is very vibrating and the sensor is faulty; the fourth kind is the deviation of the transmitter from the pointer pressure gauge. Deviation is a normal phenomenon. Confirm the normal deviation range.
The last kind of fault that appears easily is the influence of the installation position of the micro differential pressure transmitter on the zero output. Micro Differential Pressure Transmitter Since the measurement range is very small, the sensor components in the transmitter will affect the output of the micro differential pressure transmitter. When installing, the pressure sensitive part of the transmitter should be perpendicular to the direction of gravity. After installation, adjust the transmitter zero to the standard value.
Zero drift causes zero drift of the pressure sensor for several reasons:
1 strain gauge adhesive layer with air bubbles or impurities
2. The performance of the strain gauge itself is not stable
3. There are solder joints in the circuit
4. The stress release of the elastomer is not complete; it is also related to many fields such as magnetic field, frequency and temperature. Electric drift or some drift will exist, but we can narrow it down or correct it in some ways.
Zero thermal drift is an important indicator that affects the performance of pressure sensors and has received extensive attention. Internationally, it is considered that the zero-point thermal drift only depends on the inequality of the force-sensitive resistor and its temperature nonlinearity. In fact, the zero-point thermal drift is also related to the reverse leakage of the force-sensitive resistor. In this regard, the polysilicon can absorb heavy metal impurities in the substrate, thereby reducing the reverse leakage of the force-sensitive resistor, improving the zero-point thermal drift, and improving the performance of the sensor.
What are the ways to reduce electrical drift and correct electrical drift? Zero electrical drift In addition to affecting the pressure sensor's measurement accuracy and lower sensitivity, what are the other important effects?
The use of zero electrical drift can eliminate the thermal zero drift of the pressure sensor. The so-called zero drift refers to the phenomenon that when the input of the amplifier is short-circuited, there is an irregular, slowly changing voltage at the input. The main cause of zero drift is the influence of temperature changes on the transistor parameters and the fluctuation of the power supply voltage. In most amplifiers, the zero drift of the previous stage has the greatest influence. The more the number of stages and the greater the amplification, the worse the zero point drift. .
The size of the drift mainly lies in the selection of the strained material. The structure or composition of the material determines its stability or heat sensitivity.
After the material is selected, the processing is also very important. If the technology is different, the strain value of different effects will be produced, and the key is also the stability of the bridge value or the change of the process law after adjustment by some aging and the like.
There are many means of adjusting the drift, most of which are determined by the manufacturer's conditions or production requirements. Most manufacturers control the zero drift well. Temperature adjustment can be compensated by internal temperature resistance and heating zero-sensitivity resistance, aging and so on.
For transformers that use circuit conversion, the drift of the circuit can be compensated by selecting the good components and designing a more suitable circuit.
Strained materials are selected for materials with high sensitivity coefficients and small temperature changes.
Fault Detection The majority of failures that occur on construction sites are due to improper use and installation of pressure sensors. There are several aspects that can be summarized.
1. The primary component (orifice plate, remote measurement connector, etc.) is blocked or improperly installed, and the pressure point is not reasonable.
2. Leakage or blockage of the pressure tube, residual gas in the liquid filling tube or residual liquid in the gas filling tube, deposits in the process flange of the transmitter, forming a dead zone for measurement.
3, the transmitter wiring is not correct, the power supply voltage is too high or too low, indicating that the header and the meter terminal connection is bad.
4. The installation was not strictly in accordance with the technical requirements. The installation method and the on-site environment did not meet the technical requirements. 