Application and principle of differential pressure transmitter
是丈量变送器两端压力之差的变送器,输出规范信号(如4~20mA,1~5V)。 The differential pressure transmitter is a transmitter that measures the pressure difference between the two ends of the transmitter and outputs a standard signal (such as 4 ~ 20mA, 1 ~ 5V). Different from ordinary pressure transmitters, differential pressure transmitters have two pressure interfaces. Differential pressure transmitters are generally divided into positive pressure terminals and negative pressure terminals. Under normal conditions, differential pressure transmitters have positive pressure. The pressure at the end should be greater than the pressure in the negative pressure section to measure. The practical application of the differential pressure transmitter in the oil depot project, the design conditions: 2000m3 oil tank, diameter d = 14.5m, height can get the actual oil inventory G, from the formula can also know its density ρh = 14m. One-time meter: Z351 / 1151DP flange type flameproof differential pressure temperature transmitter of Shandong Feichuang Instrument Co., Ltd. is selected. The flange type is used to avoid sedimentation of the bottom of the tank and infarct the pressure tube. . Secondary meter: Use the company's FWP series intelligent light bar to display the current alarm device, universal signal input, can change the range arbitrarily, use the light bar to display the liquid level, and digitally display the tonnage of oil products. Take 6 # tank as an example, S = π × r2 = 3.14 × 7.252 = 165m2, and the height is 14m. 设计一套液位报警安装，避免油品满溢，作为双保险。 On the top of the oil tank, a differential pressure transmitter is designed to install a liquid level alarm to prevent oil overflow, as a double insurance. In the application, the measured value is directly ton, so no matter what kind of oil is stored in the oil tank, the value shown in the secondary table is the number of tons of oil in the oil tank, which prevents the trouble of measuring the density and stopping conversion. Differential pressure transmitters are usually put in and out of the warehouse using a pump to pass through an ellipse gear meter. Because the accuracy of the flow meter is limited, the maximum is only 0.2.
Microprocessor-based field smart meters are produced in accordance with the field bus. Similarly, the application of field smart meters also provides a good foundation for field bus development and application and raises new questions for expert research. At this stage, the on-site intelligent instrument, as introduced in related literature, is a compelling transition product due to the incompatibility of communication protocols and the holding point of 4-20mA analog signal transmission of conventional instruments. Really intelligent field instruments that can't really adapt to fieldbuses. It can neither reduce the initial installation cost of the control system, nor can it give full play to its own superior functions, nor can it realize the mutual information exchange and operation between field intelligent instruments.
毕竟代表着新一代变送器的崛起，它采用了当今不少高新技术，如传感技术，微电子数字处理技术等，与常现变送器相比，具有精度高、稳定性好、可靠性高、测量范围宽、量程比大等特定。 However, the differential pressure transmitter, after all, represents the rise of a new generation of transmitters. It uses many high-tech technologies such as sensing technology and microelectronic digital processing technology. High, good stability, high reliability, wide measuring range, large range ratio, etc. Even more advantageous is that it implements digital communication functions. Through the DCS system or field communication controller with the same communication protocol, various parameters of the smart transmitter can be changed and set to achieve remote debugging, man-machine dialogue, and online monitoring of various data. Like all smart meters, smart transmitters also have comprehensive self-diagnostics. It can be said that the current smart transmitter is a new type of transmitter that replaces the past and represents the future development of field instruments.