The difference between loop control and direct control in automatic fire alarm system
Source: Vedard Security Alarm
Date: 2024/04/19
https://vedard.com/blog/the-difference-between-loop-control-and-direct-control-in-automatic-fire-alarm-system/
The loop control mainly solves the problem of quick operation control of loop control equipment, and the Direct control mainly solves the problem of direct manual control of important equipment (fire pumps, smoke prevention and smoke exhaust fans, etc.).
1. Loop control panel
1. According to the requirements of the Fire Secutriy specification, the fire linkage controller should have the function of manual control of each controlled equipment. The loop control panel provides a convenient way to start and stop the loop (control) device, which can replace the cumbersome menu operation.
2. The loop control panel is equipped with a plurality of operation buttons, each button corresponds to a starting light and a feedback light, which are respectively used to prompt the button status and display the running status of the equipment. Each button of the loop control panel can be programmed to control all types, partitions and specific components. (Note: Functions vary by manufacturer)
3. Although the specification does not mandate the setting of the loop control panel, in many cases, for some controlled equipment that needs to be operated in time, especially multiple devices controlled by partitions, it is necessary to effectively control the loop control panel.
For example, for the smoke prevention and exhaust system, the buttons of the loop control panel can be programmed to activate all the smoke exhaust ports (valves) of a certain smoke prevention zone with one click. It is also possible to set a button to activate the pressurized air supply outlets of all front rooms in a fire zone.
2. Direct control
According to the requirements of the code, important equipment such as fire pumps, smoke-proof fans, and smoke exhaust fans should have the function of manual direct control in the fire control room (or duty room). This function loop fire control panel can not meet the requirements, need to be realized by the Direct control panel of the fire linkage controller (also known as direct manual control unit, direct manual control panel), the start \ stop button of the Direct control panel should be connected with the field control cabinet of fire pump, smoke prevention fan and smoke exhaust fan through a special line.
The deluge valve group, the relevant control valve group of the water curtain system, the pre-acting valve group and the electric valve before the inlet of the fast exhaust valve of the pre-action system should also be able to be directly started through the direct manual control unit of the fire linkage controller of the fire control room (or duty room) and connected through a special line.
Example: In the pre-action system shown in the figure, the starting device of the pre-action valve group, the electric valve in front of the inlet of the fast exhaust valve and the starting cabinet of the fire pump group should be connected to the Direct control panel of the fire alarm linkage controller by special lines respectively to achieve manual direct control.
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