Smart pressure transmitter calibration steps

　　Smart pressure transmitter calibration steps

　　The calibration and inspection steps of 154608PDS series intelligent pressure transmitter are as follows:

　　1. Unscrew the side cover of the transmitter terminal, connect the 24V power supply in series with the 0~20mA ammeter to the +/- marked terminal, and preheat for 15 minutes.

　　2. Unscrew the two screws on the transmitter button protection cover and lift up the button protection cover.

　　3. Press the "M" key to check whether parameters 2 to 14 comply with the factory nameplate markings and related technical requirements. If it is found that the zero point current of the two items deviates from 4.000+0.012mA, do not press "↑" or "↓" to make the output current meet 4.000+0.012mA according to the adjustment method in the operation manual. Please continue to press the "M" key to find out The 7 values ​​are not 0, but display an out-of-tolerance value. At this time, press "↑" and "↓" at the same time to reset the 7 values ​​to zero, and the 2 values ​​can be automatically restored from the error state to the standard current value of 4.000mA. . This completes the zero point check and adjustment.

　　4. Turn on the pressure source and pressurize to the pressure value corresponding to the full scale. If the full scale deviates from 20.000±0.012mA, you can press "↑" and "↓" at the same time to automatically restore the three full scale values ​​from the error state. The standard current value is 20.000mA. This completes the full-scale check and adjustment.

　　5. After disconnecting the pressure source and releasing the pressure, check whether the zero point current is within 4.000±0.012mA. If there is any deviation, please continue to repeat the above 3.

　　Just 4 steps.

　　6. If the preheating time meets 15 minutes, it still does not meet the technical requirements after multiple adjustments (the zero point current is

　　4.000+0.012mA, the full-scale current is 20.000+0.012mA), the transmitter can be judged to be unqualified.

　　7. Disconnect the pressure source, tighten the two screws on the button protection cover, remove the +/- marked terminal wiring, tighten the transmitter terminal side cover, and the verification is completed.

　　Remark:

　　1. If you press "t" or "↓" in mode 2 according to the operation manual to make the zero point output current meet 4.000±0.012mA, it will cause the values ​​of items 5, 6, and 7 to change, and you will have to manually adjust these 3 items. The value returns to the standard value.

　　2. Modes 2 and 3 all display the actual working current value when the transmitter is working normally. Mode 7 and 4 items all display the actual working pressure value at that time when the smart transmitter is working normally.

　　Precautions for smart pressure transmitters

　　Please read the product sample and instruction manual carefully before installation and use. The pressure interface must not leak during installation and ensure that the measuring range and wiring are correct. The shells of pressure sensors and transmitters generally need to be grounded. Signal cables must not be laid mixed with power cables. Strong electromagnetic interference should be avoided around sensors and transmitters. Sensors and transmitters should be periodically calibrated in accordance with industry regulations during use.

　　Parameters you must know when selecting a pressure transmitter

　　The pressure transmitter is used to measure the level, density and pressure of liquid, gas or steam, and then converts it into a 4~20mA DC signal output. The intelligent pressure transmitter can communicate with the HART handheld communicator, through which it can be set, monitored or form an on-site monitoring system with the host computer. When purchasing a pressure transmitter, you must know the following parameters.

　　1. Wetted materials

　　What we have to consider is the medium measured by the pressure transmitter. Generally, the material of the contact medium part of the pressure transmitter is 316 stainless steel. If your medium is not corrosive to 316 stainless steel, then basically all pressure changes will The transmitter is suitable for your measurement of medium pressure.

　　If your medium is corrosive to 316 stainless steel, then we must use chemical sealing. This will not only measure the pressure of the medium, but also effectively prevent the medium from contacting the wetted part of the pressure transmitter, thus achieving Protect the pressure transmitter and extend the life of the pressure transmitter.

　　2. Accuracy level

　　Every electronic measuring meter will have accuracy errors, but the accuracy levels marked by each country are different. For example, the accuracy of national standards such as China and the United States is the part with the best linearity of the sensor, which is what we usually The so-called accuracy is between 10% and 90% of the measurement range; while the European standard accuracy is the worst linearity part, which is what we usually call the measurement inverse 0 to 10% and 90% to 100% accuracy between. For example, the accuracy of the European standard is 1%, and the accuracy of the Chinese standard is 0.5%.

　　3. Measuring range

　　Generally, it is best for the maximum measurement range of a sensor to be 70% of the sensor's full scale, that is, to measure a pressure of 70bar, the range of the pressure transmitter we choose should be 100bar.

　　4. Output signal

　　At this stage, due to various collection needs, there are many types of output signals of pressure transmitters on the market, mainly 4~20mA, 0~20mA, 0~10V, 0~5V, etc., but the more commonly used one is 4~20mA. and 0~10V. Among the output signals I mentioned above, only 4~20mA is a two-wire system (what we call the output does not include grounding or shielding wires), and the others are three-wire system.

　　5. Medium temperature

　　Since the signal of the pressure transmitter is partially converted through the electronic circuit, under normal circumstances, the measurement medium temperature of the pressure transmitter is -30 to +100 degrees. If the temperature is too high, we generally use a condensation bend to cool it. Medium, this will reduce the cost of having the manufacturer specially produce a high-temperature-resistant pressure transmitter for you.

　　6. Measuring medium

　　Generally, what we measure is relatively clean fluid, so we can just use a standard pressure transmitter. If the medium you are measuring is easily crystallized or viscous, we generally use an external diaphragm. Or used together with a chemical seal, which will effectively prevent the medium from blocking the pressure measurement hole.