3151/3051投入式液位变送器的传感器局部可直接投入到液体中，变送器局部可用法兰或支架固定，装置运用极为便当，应用静压式采用洛斯蒙压力传感器原装组件消费，主要用于城市给排水，水处置厂、水库、河流、海洋、储油罐、及石油、化工、电力等部门的液位丈量。
The sensor part of 3151 / 3051 input type liquid level transmitter can be directly put into the liquid. The transmitter can be fixed by flange or bracket, so the device is very convenient to use. The static pressure type adopts the original components of losmond pressure sensor. It is mainly used for the liquid level of urban water supply and drainage, water treatment plant, reservoir, river, ocean, oil tank, petroleum, chemical and electric power departments Measurement.
被测介质能够是水、油、酸性、碱性及稀薄性液体。仪表输出二线制4~20mADC规范电流信号，具有技术先进、精度高、质量稳定牢靠，装置运用便当等优点，是一种过程检测控制系统中理想的液位仪表。
The measured medium can be water, oil, acid, alkaline and thin liquid. The instrument outputs 4 ~ 20mADC standard current signal with advanced technology, high precision, stable and reliable quality, and easy to use. It is an ideal liquid level instrument in process detection and control system.
3151/3051投入式液位变送器采用静液压测量原理，当测量探头放入液体中时，设大气压力为Po，液面到测量元件高为h，液体密度为r，当地重力加速度为g，则变送器探头上所受压力为：Pl＝Po+r×g×h，敏感元件的负侧通过导气电缆与大气相通所受压力为：P2=Po于是测量元件所测到的压力差值为：P= Pl-P2=r×g×h，对于特定的液体介质和确定的地区，r和g均为常数，于是P口h，即可由仪表输出电流大小得到液位高度，即水深。
The 3151 / 3051 input type liquid level transmitter adopts the principle of hydrostatic pressure measurement. When the measuring probe is put into the liquid, the atmospheric pressure is Po, the height from the liquid level to the measuring element is h, the liquid density is r, and the local gravity acceleration is g, then the pressure on the probe of the transmitter is: PL = Po + R × g × h, and the negative side of the sensitive element is connected with the atmosphere through the gas conducting cable, and the pressure is P2 = Po The measured pressure difference is: P = pl-p2 = R × g × h. for a specific liquid medium and a certain area, R and G are constants, so the liquid level height, i.e. water depth, can be obtained from the output current of the instrument at port P H.
3151/3051投入式液位变送器给水工控使用原理
Application principle of 3151 / 3051 input type liquid level transmitter for water supply industrial control
因为数据不准确的原因来自水流的冲击，那么我们安装投入式液位变送器时只要避免液体下流时压力直接冲击探头，或者用其他的物体挡住液体下流时候那瞬间直接冲击的压力就可以了。
Because the data is not accurate because of the impact of water flow, so when we install the input type liquid level transmitter, we only need to avoid the direct impact of the pressure on the probe when the liquid flows down, or use other objects to block the pressure of the instant direct impact when the liquid flows down.
方法一、把进水口装成淋浴式的，把一股大水流切断成小水流喷洒下来，效果还不错；
Method 1. Install the water inlet into a shower type, cut off a large stream of water and spray it down into a small one, and the effect is good;
方法二、把进水管口弯一下，使进水口略微往上翘一点，水在出来时会*先往空中抛然后再落下，减少了直接冲击(将动能转换成势能)。
Method 2: bend the inlet pipe to make the water inlet slightly upward. When the water comes out, the water will be thrown into the air first and then fall down, thus reducing the direct impact (converting kinetic energy into potential energy).
方法三、在水中安装内径45mm左右钢管，水流入口反方向位置打若干小孔，液位计探头安装在钢管内可以减少冲击，提高稳定性。
The third method is to install a steel pipe with an inner diameter of about 45mm in the water. A number of small holes are drilled in the opposite direction of the water inlet. The probe of the liquid level meter is installed in the steel pipe, which can reduce the impact and improve the stability.
3151/3051投入式液位变送器给水工控使用原理
Application principle of 3151 / 3051 input type liquid level transmitter for water supply industrial control
·注明测量范围（液位高度），对于一些特殊介质，注明介质的密度。
·Indicate the measurement range (liquid level height), and for some special media, indicate the density of the medium.
·选型时，应注意被测介质与产品接触的材料相兼容，对于特殊介质，可订制。
·When selecting the type, it should be noted that the tested medium is compatible with the material contacted with the product. For special media, it can be customized.
·将投入式液位变送器安装于多雷雨地区时，订货时应注明“防雷”，建议用户在现场安装防雷击保护装置，并确保产品及电源接地。
·When the input type liquid level transmitter is installed in Thunderstorm area, the "lightning protection" shall be indicated when ordering. It is suggested that the user should install lightning protection device on site and ensure that the product and power supply are grounded.
·关于导气电缆长度的选取：一般比实际液位高度长10cm，不宜太长，如果现场到控制柜距离很远，请选用优质导线电缆代替，不需要导气电缆，导气电缆做引线，使用中会出现问题，由于环境因素、工人因素如乱踩会使投入式液位变送器的导气性能变差，乱压造成气不通，乱折容易把出气口睹起来。建议用优质电缆代替，就不会出现以上故障了！
·The selection of gas conducting cable length: generally, it is 10cm longer than the actual liquid level height, and should not be too long. If the distance from the site to the control cabinet is far away, please use high-quality conductor cable instead. There is no need for gas conducting cable. As the lead wire, there will be problems in the use. Due to environmental factors and workers' factors, such as trampling, the air conduction performance of the input type liquid level transmitter will be deteriorated and the pressure will be disorderly It is easy to see the air outlet if the air is blocked. It is recommended to use high-quality cable instead of the above fault!
3151/3051投入式液位变送器给水工控使用原理
Application principle of 3151 / 3051 input type liquid level transmitter for water supply industrial control
二次仪表的硬件设计主要包括电源设计，A/D转换设计，单片机外围电路设计，显示、报警、继电控制设计，远端通讯设计等。电源设计主要考虑变压器应有足够的耐压和功率的降额设计，变压器屏蔽层应接地。二次仪表中的模拟部分和数字部分及控制继电器应由不同的变压器副边线圈供电，以防止大脉冲电流和电源波动的影响。整个电源在线路板的布局应远离信号线路部分。
The hardware design of secondary instrument mainly includes power supply design, a / D conversion design, MCU peripheral circuit design, display, alarm, relay control design, remote communication design, etc. The power supply design mainly considers that the transformer should have enough withstand voltage and power derating design, and the shielding layer of the transformer should be grounded. The analog part and digital part of the secondary instrument and the control relay should be powered by different transformer secondary coils to prevent the influence of large pulse current and power supply fluctuation. The layout of the whole power supply in the circuit board should be far away from the signal circuit part.
A/D转换芯片的选取应注重于产品的稳定性和可靠性，产品在出厂前应经过严格的老化和筛选。A/D的外围电路的设计应特别注意参考电压的稳定性。单片机外围电路设计以基本程式化，但其通讯端口的软硬件设计与A/D转换芯片的数据交换方式有关，液位测量对测量频率要求不高，单片机与A/D转换芯片之间的数据交换可采用串口查询方式，这样程序结构清晰，便于编写和调试。
The selection of a / D conversion chip should pay attention to the stability and reliability of the product, and the product should go through strict aging and screening before leaving the factory. Special attention should be paid to the stability of reference voltage in the design of peripheral circuit of a / d. The peripheral circuit design of single chip microcomputer is basically programmed, but the software and hardware design of its communication port is related to the data exchange mode of a / D conversion chip. The requirement of measurement frequency for liquid level measurement is not high. The data exchange between single chip microcomputer and a / D conversion chip can adopt serial port query mode. This program structure is clear and easy to write and debug.