The alarm system based on the professional bus form is currently the most widely used, and the aerial bundled cable SANS 1418 is also the most complicated, so I will focus on the discussion here.
RVV2*0.3 (signal cable) and RVV4*0.3 (2-core signal + 2-core power supply) cables are generally used between the front-end detector and the alarm controller, and the two aerial bundled cables ASTM B231 are generally used between the alarm controller and the terminal security center. As for the core signal wire, as for the use of shielded wire or twisted pair or ordinary sheathed wire, it needs to be determined according to the requirements of various brands of products. The thickness of the wire diameter is determined according to the distance and quality of the alarm controller and the center. First of all, determine the location of the security center and the distance between each alarm controller. The farthest distance cannot exceed the length specified by various brands, otherwise it will not meet the requirements of the bus; the entire alarm area is relatively large, the bus must not meet the requirements Under the conditions, the alarm can be divided into several areas. In each area, determine the installation location of the sub-control center to ensure that the bus in the area meets the requirements, and determine the location of the general management center and the sub-management center, and determine the sub-control center to the general management The communication method of the center is to adopt RS232-RS485 conversion transmission or adopt RS232-TCP/IP to use the integrated wiring system of the community for transmission or the management software of the sub-management center to use TCP/IP network to forward to the general management center.The power supply of the alarm controller generally adopts local power supply instead of centralized power supply in the control room. The line is relatively short. Generally, RVV 2×0.5” or more specifications can be used. Configure according to the actual line loss. Perimeter alarm and other public area alarm equipment power supply Generally, the centralized power supply mode is adopted and the line is longer. Generally, the specifications above RVV2*1.0″ are adopted, and the configuration is based on the actual line loss. The grounding of all power cable must be unified.
Different types of alarms (such as perimeter alarm, public area alarm bus and household alarm bus separately) should not use the same bus. The installation location of the junction box should be easy to operate, and the high-quality junction interface is used to handle the connection between the bus and the bus, which is convenient for maintenance. And debugging; it is recommended that the bus and other lines take charge of the wiring. The bus weakening bridge should be kept away from other lines according to the weak current standard to avoid causing unshielded non-twisted pair audio lines and other high and low frequency interferences such as video intercom systems.