With the continuous development of society, electronic pressure gauges are gradually being adopted by many industries. The so-called electronic pressure gauge is what we usually call a pressure transmitter . Due to the influence of factors such as working environment, medium and medium temperature, it is important to pay attention to the following points when selecting a pressure transmitter :
首先是压力变送器所测量的介质 , 一般情况下， 压力变送器接触介质的部分材质采用的是 316 不锈钢。 1. The first is the medium measured by the pressure transmitter . Generally, the material of the part of the pressure transmitter that contacts the medium is 316 stainless steel. 316 不锈钢没有腐蚀性，那么所有的压力变送器都适合对介质压力的测量。 If the contacting medium is not corrosive to 316 stainless steel, then all pressure transmitters are suitable for measuring the pressure of the medium. 316 不锈钢有腐蚀性，那么就要采用化学密封的措施，这样不仅可以测量介质的压力，而且可以有效的阻止介质与压力变送器接液部分的接触，起到保护压力变送器，延长了压力变送器的使用时间。 However, if the contacted medium is corrosive to 316 stainless steel, then chemical sealing measures must be adopted. This not only can measure the pressure of the medium, but also effectively prevent the medium from contacting the wetted part of the pressure transmitter to protect the pressure Transmitter extends the life of the pressure transmitter.
无论是那种电子式的测量计都会有精度的误差，但是由于每个国家所标的精度等级不一样的，比如：中国和美国等国家标的精度是传感器在线性度最好的部分，也就是我们通常所说的测量范围的 10% 到 90% 之间的精度；而欧洲标的精度则是线性度最差的部分 , 也就是我们通常所说的测量反的 0 到 10% 以及 90% 到 100% 之间的精度。 2. No matter which kind of electronic measuring meter will have accuracy error, but because the accuracy level of each country is different, for example: China and the United States and other national standard accuracy is the best linearity of the sensor. It is what we usually call the accuracy between 10% and 90% of the measurement range ; and the European standard accuracy is the worst part of linearity , which is what we usually call the measurement inverse 0 to 10% and 90% to 100% accuracy.
一般传感器的满量程 70% 是传感器测量的最大范围，并且这样是最好的，也就是说如果现在要测量 70kar 的压力，那么选压力变送器的量程应该选 100kar 。 3. Generally, 70% of the full range of the sensor is the maximum range of the sensor measurement, and this is the best. That is to say, if the pressure of 70kar is to be measured now , then the range of the pressure transmitter should be 100kar .
由于目前不同的需要，现在市场上压力变送器的输出信号有很多种，主要有 4~20m A ﹑ 0~20m A ﹑ 0~10 V ﹑ 0~5V 等等，但是一般比较常用的是 4~20mA 和 0~10V 两种，在以上的这些输出信号中 , 只有 4~20mA 为两线制，其他的均为三线制。 4. Due to different needs at present, there are many kinds of output signals of pressure transmitters on the market, mainly 4 ~ 20m A , 0 ~ 20m A , 0 ~ 10 V , 0 ~ 5V, etc., but generally used There are two kinds of 4 ~ 20mA and 0 ~ 10V . Among the above output signals , only 4 ~ 20mA is two-wire system, and the others are three-wire system.
因为压力变送器的信号是通过电子线路部分转换的，所以一般情况下， 压力变送器的测量介质温度为 -3 0 ～ +100 度。 5. Because the signal of the pressure transmitter is converted by the electronic circuit, in general, the temperature of the measuring medium of the pressure transmitter is -3 0 to +100 degrees. If the temperature is too high, the condensing bend is usually used to cool the medium. This will reduce the cost by allowing the manufacturer to produce a high temperature pressure transmitter.
一般测量的流体是相对比较清洁，可以直接采用标准的压力变送器就可以了，但是如果所测量的介质是易结晶的或者粘稠的，一般会采用外置膜片或者和化学密封共同使用，这样会有效的阻止介质堵住压力测量孔。 7. Generally the measured fluid is relatively clean, and a standard pressure transmitter can be used directly, but if the measured medium is easy to crystallize or sticky, an external diaphragm or chemical seal is generally used. Together, this will effectively prevent the medium from blocking the pressure measurement hole.
When the above points are determined, the process connection interface of the pressure transmitter and the power supply voltage of the pressure transmitter must be confirmed. If it is used in special explosive situations, the explosion protection and protection level must also be considered.