Alarm switchboard visual displays and audible outputs

On the main alarm panel, there are two ground indicator lamps to indicate the presence of a ground in the alarm system. All shipboard alarm panels and remote sensors are electrically isolated from the ship’s ground. The only exception is the ground fault de- tector, which is connected to ground for ground monitoring. If one or both lamps light, you should have the alarm SWBD and its remote sensors serviced by an electrician who has maintenance responsibility for removing a very dangerous shock hazard. The AUDIBLE silence control is a two-position switch that permits silencing (VISUAL position) the audible alarm on the main panel. The ALARM lamp on the main panel is lighted when the AUDIBLE silence control is placed in the VISUAL position, and the sys- tem is in an alarm condition. The lower half of the alarm panel holds the alarm modules that are connected through the alarm panel to the remote sensors. If additional remote sensors are installed at a later date, a new alarm module is plugged into the lower panel for each sensor installed. Each alarm module includes a center-divided lighted display. Either half can independently display a steady red light, a flashing red light, or no light, depending on the circuit logic. The six possible combinations of alarm module lights and the appropriate audible alarm are shown in figure 2-23. Figure 2-23.—Alarm switchboard visual displays and audible outputs. 2-25