What Is an Extension Cord?

Extension line is based on the established line, from a certain end point, to continue to extend the work direction of the established line, after the final completion, it can still be regarded as a line.

Based on the experience of operation and system integration construction and acceptance, discuss and analyze the new functions of the Guangzhou Metro Line 3 integrated monitoring system, as well as the expansion methods and methods of the extension line and the first phase in the Operation Control Center (OCC). The further integration of resource planning (ERP) technology presents an outlook. ^[1]

This paper introduces the docking and joint adjustment method of the AFC system and the comprehensive monitoring system in the comprehensive joint adjustment when the automatic ticket sales (AFC) system of the extension line of the Xi'an Metro Line 2 is connected to the existing running system. By setting up a simulation test environment, adding redundant servers, and adjusting the joint adjustment time, the existing AFC joint adjustment time constraints, extension lines, and first-phase engineering data when the AFC system of the extension line 2 is connected to a normal monitoring system that is already in service are solved. Difficulties such as inconsistent point tables, etc., have achieved the interconnection of the extension line AFC and comprehensive monitoring data without affecting the normal operation of the existing system, and put forward a constructive idea for the same type of extension line access project under construction in China. ^[2]

AFC Extension cable AFC system network architecture

The extension line is based on the existing lines that have been in operation for a period of time. In order to expand the line network operation needs, the original line system design is used, and several stations are added to maintain the extension of unified software and hardware equipment, data transmission mechanisms and interface specifications. line.

The upper central computer system of the 4 new stations of the extension line and the 17 stations of the first phase of the project use the original central computer system. The data transmission with the integrated monitoring system is also connected through the server in the central computer system, and is realized through the same small sorting system. Data interaction for the One Card and Line 1 AFC system. ^[2]

Extension line butt problem in extension line

Extension cables have the same basic debugging methods as newly opened lines. As the first phase of the Line 2 project has been opened for operation, in order to ensure the normal operation of the AFC system of the first phase of the project, it should be consistent with the first phase of the project as far as possible during the data information access of the extension line and the interoperability with ISCS Software platform to reduce the impact and interference on the existing system operation of the first phase of the project, to achieve smooth access to extension lines. However, because the engineering commissioning period of the AFC system is close to the opening period and other factors, it has problems in coordinating with the comprehensive joint adjustment of ISCS. ^[2]

Extension cable data connection scheme

In order to achieve the smooth transition without affecting the operation of the first-phase AFC when the extension line is included, it is necessary to add a redundant server to the CC to realize the transformation of the CC server. This set of redundant servers will only be used for testing during the system joint debugging. The system will be evacuated after the system is officially running. In the transformation scheme of the CC server, the real-time server should adopt a "cluster-like" architecture, that is, a service group that is jointly operated by multiple servers. Two additional real-time servers that are redundant will be connected to each station of the extension line, and all data of the extension line will be stored in the newly added disk array. The newly added real-time server and the original line 2 central server run side by side in the control center. In the early stage of testing and joint adjustment of the data of the newly added server and the extended line, the two sections of the line were physically separated (firewall) through the software settings of the central switch. The debugging of the extended line system will not affect the original line 2. The data flow of the server has no effect, and the ISCS of line 2 still maintains the stable operation of the original system. ^[2]