是一种数字化的变送器，使用手持通信器或采用遵循相关协议的其他主机可在控制室、现场或在同一控制回路的任何地方，同其进行双向通信。 A smart transmitter is a digital transmitter that uses a handheld communicator or other host that follows the relevant protocol to communicate with the control room, on-site, or anywhere in the same control loop. At the same time, it also has some advanced functions, such as the operator does not need to be on site, as long as the handheld communication or DCS operation station keyboard in the operating room, you can easily set and modify various parameters of the field smart transmitter Or fault inspection, which greatly reduces the labor intensity of workers, and also facilitates process production. Smart transmitters have been promoted very quickly in petrochemical enterprises. However, some problems have also been encountered in the use of smart transmitters and instrument maintenance. Practical measures have been taken to solve the problems in the actual work and achieved good results. effect. Smart transmitters are generally hybrid smart transmitters that have both digital and analog signals. The communication with DCS is based on transmitting 4-20mA analog signals, and then superimposing digital signals on them for remote setting. Zero point, range, and calibration, configuration, and diagnostics of the transmitter. It is only designed to be compatible with the existing DCS, and it is a transition product of true all-digital intelligent transmitters (such as fieldbus-type intelligent transmitters).
有哪些组成：一般是由传感器、微处理器、存储器及模数、数模转换器组成。 What are the components of a smart transmitter : Generally it consists of sensors, microprocessors, memories, and analog-to-digital, digital-to-analog converters. The sensor is used to detect the signal being measured. The materials used vary from manufacturer to manufacturer. Yokogawa EJA is a silicon resonance type, which converts the measured parameter to the vibration frequency of the silicon beam; the ST300 sensor is a diffused silicon compound semiconductor type, which converts the measured parameter into changes in the resistance value of the silicon chip; 1151, 3051, and Fuji FCX -A / C is a silicon microcapacitor type. The measured differential pressure or pressure value is obtained by measuring the capacitance, while the 8600 series smart transmitter is an inductive type. The microprocessor is the core of the smart transmitter and is responsible for the comprehensive calculation and processing of the data, such as linearizing the detection signal, readjusting the range, calculating the function, converting the work unit, and diagnosing and communicating functions. The memory is used to store various constants, programs and transmitter configurations that are called by the microprocessor, and are now generally rewritable. Analog-to-digital and digital-to-analog converters are used to convert analog signals and digital signals. The detection signals from the sensors to the microprocessor must use analog-to-digital converters, and the microprocessor output 4 to 20 mA signals must use digital-to-analog converters. The smart transmitter needs to output a digital signal to communicate with the DCS, and is attached with a smart field communicator (SFC) or hand programmer to communicate with the transmitter. In addition, the smart transmitter is equipped with a backup power supply to avoid data loss in the memory in the event of a power failure. What are the characteristics of smart transmitters: 1 wide range, large range ratio; 2. simple and convenient maintenance; 3. high and low voltage side conversion function. Smart transmitter has a wide range and a large range ratio. Generally, it has a wide range and a large range ratio, from 30: 1 to 100: 1, and some even reach 400: 1. The range ratio of the transmitter refers to the ratio of the maximum measurement range (URV) to the minimum measurement range (LRV) . Compared with conventional analog transmitters, the biggest advantage of smart transmitter ranges is that they can reduce the amount of inventory. At the same time, according to process requirements, the range can be changed at any time without replacing the meter, without worrying about the range exceeding the limit. It is very convenient to use the smart transmitter. It is sufficient to adjust the range online, without having to replace the meter. If it is a conventional analog transmitter, replace the new meter with a larger range.
和DCS系统资料;对现场仪表和DCS系统正常运行的技术要求须做深人细致的探讨;并结合工作实际，发挥仪表工程技术人员的智慧，处理好智能变送器的供电和阻抗匹配问题，从而为提高仪表维护水平，为智能变送器的推广使用，也为提高石油化工生产的自动化水平创造条件。 In the process of use and maintenance, it is necessary to carefully read the information of smart transmitters and DCS systems; the technical requirements for the normal operation of field instruments and DCS systems must be thoroughly discussed; and the wisdom of instrument engineering technicians should be brought into play in combination with the actual work , Handle the power supply and impedance matching of smart transmitters well, so as to improve the maintenance level of the instrument, promote the use of smart transmitters, and also create conditions for improving the automation level of petrochemical production. Simple and convenient maintenance of the smart transmitter: The handheld communicator can communicate with the smart transmitter at the terminal of the field transmitter or the terminal in the control room of the main control room. In this way, the instrument maintenance personnel can perform range modification, parameter setting, and instrument maintenance on the transmitter in a relatively safe and good surrounding control room. It should be noted that the handheld communicator cannot be directly connected to the two ends of the power supply that supplies power to the transmitter in the instrument control loop. The reason is that the power supply has low impedance and the handheld communicator cannot read information at both ends. Generally, the loop resistance is required 250 ～ 600Ω, the resistance is too small to communicate, if the resistance is too large, the transmitter will work abnormally. The intelligent transmitter has the characteristics of high and low voltage side conversion function: Generally, it has the function of high and low voltage side conversion of the sensor, and the internal parameters can be adjusted with a handheld communicator. I have encountered such a problem in production. Since the meter has been running for many years, the pressure guiding tube connected to the transmitter needs to be replaced due to leakage. After the replacement, the positive and negative phase pressure guiding tubes are found to be reversed (because the pressure guiding tube It is longer, and there is a heat tracing tube together, the positive and negative phases are easily reversed). If the two pressure guiding tubes are interchanged, the workload is large. The smart transmitter has high and low voltage side conversion functions.