Bently 3500/40 176449-01 Speed Card

Bently 3500/40 176449-01 Speed Card

Large rotating machinery is a key power equipment in industrial sectors such as petrochemicals and power. Real time monitoring of the working status of these machines is of great guiding significance for ensuring their safe operation. These key equipment are equipped with sensors to automatically and continuously monitor the operating parameters of the machine, but these instruments can only display and record the amplitude of the monitored signal, prompt whether the signal amplitude exceeds the standard, cannot record complete original data, and do not have analytical functions (the information reflected by the vibration signal spectrum is much more than the vibration amplitude), especially cannot record the original data at the time of sudden fault occurrence, making it difficult to find the cause of the accident [1]. In order to improve the monitoring level of Guangzhou Petrochemical’s three major ethylene cracking compressor units (cracking gas compressor PY1300, ethylene compressor PY1600, and propylene compressor PY1650), and to achieve networked online monitoring and analysis of unit vibration and main process parameters, Guangzhou Petrochemical’s ethylene unit used the rotating machinery status monitoring and analysis system developed by S8000 Chuangwei Company in the 2003 major overhaul and renovation, to achieve status monitoring, process data accumulation, signal analysis, and fault diagnosis of the unit, and ultimately provide decision-making assistance for unit maintenance.

S8000 System Function Introduction S8000 system is an online status monitoring and analysis system for large key units (compressors, steam turbines, generator sets, blast furnace fans, etc.) in industries such as petroleum, chemical, power, and metallurgy. It provides users with comprehensive and in-depth analysis of the operating status of the unit, providing real, effective, and reliable data. The structure and functions of the system are as follows:

2.1 System Composition and Network Structure The S8000 system consists of a monitoring substation NET8000, a central server WEB8000, and a browsing station, among which data transmission is achieved through an enterprise LAN. The monitoring substation NET8000 is responsible for real-time collection of on-site unit data and continuously sending it to the central server WEB8000. The central server is responsible for storing the historical data of the unit and publishing the unit operation information to the enterprise LAN in a WEB manner. The browsing station within the LAN is located on any computer in the network. Users of the browsing station can monitor and analyze the operation of the unit online through the IE browser, without the need to install specific client software. In addition, the central server can transmit data to the Internet in a specific way through the firewall of the enterprise network, enabling Internet wide browsing; By remotely logging into the server through telephone dialing, users can perform routine maintenance and S8000 system upgrades on the server, allowing them to fully focus on monitoring and diagnosing the unit.

2.2 MODBUS communication monitoring substation NET8000 has two standard RS-232C compatible serial interfaces. Through communication with DCS or other intelligent instruments, the signal for monitoring related process quantities can be expanded to 256 channels. The application layer protocol is MODBUS transmission mode, and the monitoring substation NET8000 can serve as both the master and slave stations.

2.3 Sensitive Monitoring Based on Self Learning – S8000 Core Monitoring Concept The traditional monitoring and analysis system’s alarm monitoring only includes the main alarm and pre alarm of the total vibration value, which is far from sufficient to fully reflect the actual operating status of the unit. As the core monitoring scheme of the system, the S8000 system proposes the concept of “sensitive monitoring”. The sensitive monitoring concept is a comprehensive concept about system alarm monitoring, statistical learning, and historical data storage. The system can provide comprehensive monitoring of the vibration vector and its variation types for different units. Significantly increased the amount of monitoring information and improved monitoring sensitivity. Sensitive monitoring has self-learning function, collecting all information during the normal operation stage of the unit, and using specialized mathematical statistical algorithms to statistically learn this information, in order to obtain the monitoring threshold value of the unit in the corresponding working state. Truly achieved targeted monitoring of the daily operation of the unit.

2.4 High density start stop monitoring with automatic triggering is very important for unit start stop data. The S8000 system adopts automatic trigger start stop monitoring, which automatically determines that the start stop time is less than 0.3 seconds, and the start stop data density can reach up to 20 to 50 sets of data per second. Automatic recognition of start stop data collection without manual intervention. The system can automatically identify and trigger start stop waveform recording based on changes in speed. The start stop process does not interfere with normal monitoring, and can capture data for multiple units starting and stopping simultaneously, avoiding data loss in special circumstances. Even in the event of an unmanned shutdown, the system can be easily implemented. During the start-up and shutdown process of the unit, normal monitoring and start-up and shutdown recording are carried out synchronously, and the operating status of the unit can be observed in real time through various graphs. It can fully retain the dynamic characteristic data and process quantity information of the rotor.

2.5 The dual storage based on events and time is different from the previous method of storing data at time intervals. Sensitive monitoring technology adopts a combination of event based and time based data storage methods, fundamentally solving the contradiction between data storage and data validity. The change in the unit state beyond the limit value (self-learning value) is called an “event”, which can trigger the data collector to collect data from each channel and record the reason for the state change [3]. In addition, in order to have a thorough understanding of the entire operation status of the unit, normal data from each channel is collected at set intervals during normal operation of the unit. This dual storage achieves less sampling when there is no fault and more sampling when there is a fault, ensuring that there is no redundant information storage unrelated to diagnosis and important unit information is not lost. Not only does it save all the sampling data, but it also greatly reduces the storage capacity.

2.6 Remote IE Browsing The S8000 system adopts IE browsing mode. After connecting to the factory network, the S8000 system can perform all monitoring and analysis work on any computer on its network without installing dedicated software through the IE browser. Meanwhile, Web8000 can also be accessed through the internet. The S8000 system supports multiple network protocols and can easily connect to factory LAN and Internet networks. Equipment management personnel at all levels do not need to rush to the site.

They can obtain various information about the status of the unit through local area networks or the Internet in the office or even at home. The software and hardware design concept of remote diagnosis, upgrading, and maintenance of S8000, which closely follows the trend of technological development, makes the remote transmission of unit information very easy. By connecting the S8000 to the Internet or through remote dialing, diagnostic experts can be invited to conduct on-site consultations on the unit, timely understanding of the unit’s condition or conducting analysis and diagnosis. Remote system upgrades and maintenance can also be achieved through the network. The monitoring substation Net8000 is both an on-site collection and analysis station and an independent running web server. Net8000 adopts specially designed chips and built-in embedded Linux operating system to build a dedicated data acquisition and analysis station, breaking the limitations of domestic systems such as PC+data acquisition card+Windows or DOS operating system, greatly improving system stability and reliability. The application of S8000 system in compressors. The S8000 system was officially put into use in April 2003 in the three major ethylene cracking compressor units of Guangzhou Petrochemical Ethylene Zone. This system consists of three NET8000 monitoring stations, one WEB800 server, and several browsing stations. Responsible for monitoring the speed, vibration, and displacement parameters of the cracking gas compressor unit PY1300, ethylene compressor unit PY1600, and propylene compressor unit PY1650, and through scientific diagnostic analysis, able to timely obtain real-time and reliable operating conditions of the unit and formulate corresponding measures. This method is highly reliable and will not cause information from other units to be unable to be collected and analyzed due to the failure of a collection card or other hardware equipment in a certain collection and monitoring substation. NET8000 sends real-time data of on-site units to the central server WEB8000 through the Guangzhou Petrochemical LAN. There is no limit to the number of browsing stations. As long as any computer connected to the network has IE 5.0 or above installed, authorized passwords can be used to log in to the webpage through the IE browser, achieving remote monitoring, analysis, and diagnosis of on-site units. The system composition structure diagram is shown in Figure 1.

3.2 Signal source: The NET8000 on-site monitoring substation is installed in the cabinet room of the ethylene zone control room. Three NET8000 units are all installed in a disk mounted manner in an independent cabinet. The measurement points of the on-site unit and corresponding monitoring stations are shown in Table 1.

3.2.1 Radial vibration and axial displacement signals for cracking gas compressor units, ethylene compressor units, and propylene compressor units are directly from the output buffer port of Bently 3300 and connected to the NET 8000 monitoring station through the manufacturer’s dedicated 25 core cable terminal module and 25 core cable. By using this method, numerous unit signals on site can be connected to the monitoring substation NET8000 through cable plugging. The on-site sensor adopts Bently Nevada’s online monitoring and protection device 3300 sensor system, which can continuously measure and monitor different mechanical parameters, such as radial vibration and axial displacement signals, and provide the operating conditions of the unit. At the same time, it can provide important information for early confirmation of mechanical faults. The Bentley Bently 3300 sensor system consists of an 8mm proximity probe sensor, extension cable, preamplifier, and indicator. This type of probe has a closed sensor coil on the surface, which generates an AC magnetic field at the front end of the probe through the high-frequency working current of the coil. When the probe is close to the rotating shaft, the shaft surface will induce eddy currents. At the same time, the closed eddy currents will also induce a corresponding magnetic field on the shaft surface, which is opposite to the alternating magnetic field effect of the probe coil. Due to the counteracting effect of the reverse magnetic field, the alternating magnetic field generated by the probe is lost, which can be detected by the preamplifier. In this way, the gap between the probe and the shaft surface can be reflected in the output voltage of the preamplifier through magnetic field coupling, and form a certain characteristic curve relationship [4].

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