Fault diagnosis and analysis of 3051 pressure transmitter in application

1. Working principle: The differential pressure from the double-sided pressure guiding tube directly acts on the two-sided isolation diaphragm of the transmitter sensor, and is transmitted to the measuring element through the sealing liquid in the diaphragm, and the measuring element will measure the differential pressure signal It is converted into the corresponding electric signal and passed to the converter, after amplifying and other processing, it becomes the standard electric signal output. Two, several application measurement methods: 1. Combined with the throttling element, the liquid flow is measured by the differential pressure value generated before and after the throttling element. 2. Use the pressure difference produced by the liquid's own gravity to measure the height of the liquid. 3. Directly measure the pressure difference of different pipelines and tank liquids. 3. Fault judgment and analysis in the application: In the process of measurement, the 3051 pressure transmitter often has some faults. The timely judgment, analysis and treatment of the faults are vital to the ongoing production. Based on the experience in daily maintenance, we have summarized some judgment analysis methods and analysis procedures. 1. Investigation method: review the sparking, smoke, peculiar smell, power supply change, lightning strike, humidity, misoperation, and mismaintenance before the failure. 2. Intuitive method: Observe the external damage of the loop, the leakage of the pressure guiding tube, the overheating of the loop, the state of the power supply switch, etc. 3. Detection method: 1) Open circuit detection: separate the suspected faulty part from the other parts to check whether the fault disappears, if it disappears, determine the fault location, otherwise you can go to the next step to search, such as: smart differential pressure transmitter If the Hart remote communication is not normal, the power supply can be disconnected from the meter body, and the transmitter can be energized for communication by adding an additional power supply on site to check whether the cable is superimposed with an electromagnetic signal of about 2kHz which interferes with the communication. 2) Short-circuit detection: Under the condition of ensuring safety, directly short-circuit the relevant part of the loop, such as: the output value of the differential transmitter is too small, the pressure guiding tube can be disconnected, and the differential pressure signal can be directly transmitted from the primary pressure valve Directly lead to both sides of the differential pressure transmitter and observe the output of the transmitter to determine the plugging and leaking connectivity of the pressure guiding pipeline. 3) Replacement detection: replace the suspected faulty part and judge the faulty part. For example, if you suspect that the transmitter circuit board is malfunctioning, you can temporarily replace one to determine the cause. 4) Subsection detection: Divide the measurement loop into several parts, such as: power supply, signal output, signal transmission, signal detection, check by subsection, from simple to complex, from table to inside, narrow the scope, and find out the fault Location. 4. Failure analysis of several typical measurement circuits: I will only take the failure of the pressure guiding tube as an example to analyze the measurement circuit failure of the 3051 pressure transmitter. 1. Blockage of the pressure guiding tube: In instrument maintenance, due to the delayed discharge of the pressure transmitter pressure tube, or the dirty or sticky medium, it is often the case that the positive and negative pressure guiding tubes are blocked. When the actual flow rate decreases from before F to after F, the static pressure in the pipeline will also decrease accordingly, and the decrease value is set to P0; at the same time, when the actual flow rate drops to after F, the P-value will also be due to the flow rate of the fluid in the pipe. Decrease and increase, set the increase value to P0'. That is: △Pu003d(P+-P0)-(P-+P0') At this time, the output value of the transmitter should decrease. 2. Positive pressure guiding tube leakage: In fact, when the leakage is very small, it is difficult for process operators or instrument maintenance personnel to find out due to various reasons. Only when the leakage is large, the measured flow rate is more than the actual flow rate. It will be discovered when there is a large error, even if the actual flow rate rises, it will always be after △P leaks<<△P before leaks, and after F leaks<3. Balance valve leakage: set the pressure before leaking to P1 and the pressure after leaking to P2 , P1u003dP1+-P1-, F1 is the output value of the transmitter before the balance valve leaks, and F2 is the output value of the transmitter after the balance valve leaks. We assume that the fluid flow in the pipeline is not changed for analysis, and the leakage pressure is PS, then: the static pressure of the positive and negative pressure guiding pipe after the leakage is: P2+u003dP1+-PS, P2-u003dP1-+PS , P2u003dP2+-P2-u003dP1-2PS, according to the relationship between differential pressure and flow rate F24. Transmitter measurement error in the case of gas flow pressure tube effusion: set the pressure of the positive pressure tube pressure point to P0+ , The pressure at the pressure point of the negative pressure guiding tube is P0-, the pressure at the positive end of the transmitter'>differential pressure transmitter is P1+, and the pressure at the negative end of the transmitter'>differential pressure transmitter is P1-. P0u003dP0+-P0-P1u003dP1+-P1- Under normal measurement: P0u003dP1 Set the flow rate in the normal measurement state as F, then Fu003dK, where K is a constant coefficient. Suppose the density of liquid water is ρ, then when the effusion height of the positive pressure guiding tube is h+, and the effusion height of the negative pressure guiding tube is h-: P1+u003dP0++ρgh+P1-u003dP0-+ρgh-P1 u003dP1+-P1-u003d(P0+)+(ρh+)-(P-+ρh-)u003dP+ρ(h+-h-) then the transmitter output is: Fu003dK when h+>h- The actual measured differential pressure increases, and the output flow signal increases. When h+ is here, due to the pressure taking method of the positive pressure catheter, as time increases, h+ is gradually greater than h-, and the measured flow rate also increases.
level gauge customized level indicator has gained a lot of popularity over the recent past.
To be the safest, most progressive domestic level gauge, relentless in the pursuit of customer and employee excellence.
The unique connections between level gaugemanufacturing and customers happen when you find ways to relate on a more personal and engaging level that goes beyond a product.
By balancing the efficiencies of new technologies with the personal touch of highly trained and motivated professionals, Guangdong Kaidi Energy Technology Co., Ltd. is able to deliver solutions and services that exceed our customers’ expectations. We thereby earn their loyalty.