The miniature pressure transmitter is mainly composed of load cell sensor, measuring circuit and process connection. It can convert the received pressure signals of gas and liquid into standard current and voltage signals (4-20mADC) to provide secondary instruments such as indicating alarms, recorders, regulators for measurement, indication and process adjustment. Generally speaking, the phenomenon or operation in which the input or output value of the transmitter is equal to or greater than the upper limit of the measurement is called full scale. The pressure transmitter has full scale, which means that the pressure of the measuring range has been measured (or exceeded). For example, in the range of 0～100, its starting point (0) is called the lower limit of measurement, also called zero point; the end point (100) is called the upper limit of measurement, also called full range. The formula of the measurement range = upper limit of measurement - lower limit of measurement.
In addition, the pressure transmitter is different from the ordinary pressure meter in that it has an analog output. For example, if the range of a pressure transmitter is 1MPa, then the measurement range of the miniature pressure transmitter is 0~1MPa. When the measured pressure is 0, it outputs 4mA, and when the measured pressure is 1MPa, it outputs 20mA (that is, full scale). For example, the measuring range is 0~1.6MPa, and the full measuring range means that the pressure has reached (or exceeded) 1.6MPa (of course, it may be lower than 0MPa). This situation usually has two meanings. One is that the measured pressure is too high compared to usual state; the other is that a pressure transmitter with a larger range should be replaced.
In order for the mini water level sensor to operate and operate normally in daily work, in addition to the above-mentioned not exceeding the range, it is important to avoid some other things, so that normal work is not disturbed. Do you know any problems to avoid during the use of the miniature pressure transmitter?
1) In the production process, for plastic raw materials, there should be sufficient "soaking time" from solid to molten state. If the extruder has not reached operating temperature before starting production, both the sensor and the extruder will be damaged to some extent. In addition, if the sensor is removed from the cold extruder, the material may stick to the top of the sensor and cause damage to the diaphragm. Therefore, before removing the sensor, confirm that the temperature of the barrel is high enough and the material inside the barrel is in a softened state.
2) Note that when measuring the liquid pressure, the pressure tap should be opened on the side of the process pipeline to avoid precipitation and slag; when measuring the gas pressure, the pressure tap should be opened at the top of the process pipeline, and the transmitter should also be installed on the upper part of the process pipeline, so that the accumulated liquid can be easily injected into the process pipeline and so on. Miniature pressure transmitters are required to be inspected once a week and once a month. The main purpose is to remove the dust in the instrument, check the electrical components carefully, and check the output current value frequently. The pressure transmitter has a weak current inside, which should be separated from strong electricity from outside.