jotron MPA 1600, User And Installation Manual, Page: 24 / 62

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User and Installation Manual
Compact MPA
5.2.9 COMPASS SAFE DISTANCE:
In order to avoid unacceptable deviation of the ships standard and steering compasses or magnetometer, the closest point of
the unit and the centre of the compass or magnetometer is govered by the table below.
So for example the minimum safe distance between the center of the steering compass and the cabinet is 220 cm.
Compass Safe Distance in cm:
Cabinet Control Unit MPA 1601 GA Alarm Panel MPA 1603
Standard 340 80 60
Steering 220 50 40
5.3 GENERAL ALARM ADJUSTMENT
The Compact MPA system has a facility for both curve form and frequency adjustment of the General Alarm.
This is a part of the system setup and must be determined either in the factory (FAT) or during System installation and
commissioning. Configuration of the GA characterisics is an option within the MPA 1600 web configuration facility, which is
described in section 6.
This tone frequency and curve form alteration facility is a configuration selection only open to Jotron or authorized
personnel.
5.4 FEEDBACK/INTERFERENCE CANCELLATION
In cases where loudspeakers are placed in the near proximity of the MPA 1601 Control unit (microphone) there is a possibility
of causing audible feedback making PA messages difficult or impossible to understand. The Compact MPA PA/GA system has
two different countermeasures in order to deal with this. Either a local mute facility in each MPA 1601 Control Unit, or by
using a temporary recording facility within the system in order to first make a recording of the message, then automatically
replay the message when finished.
5.4.1 LOCAL MUTE
In the Control Unit, MPA 1601 there is a “local mute” relay and related terminals. The local loudspeakers object to the mute
function must be connected through this relay. As long as the Control unit is idle the relay are closed and all signal messages
are passing through to the local loudspeakers. Whenever the Control unit is active (PA / Emergency PA) the relay opens and
the message is disconnected from the loudspeaker and it is locally muted. Whenever the Control Units becomes idle again
the loudspeaker is reconnected.
For connection details see chapter 9.3.
5.4.2 TEMPORARY RECORDING
When this facility is enabled in the system configuration, the Compact MPA system will not immediately output the message
when a PA or Emergency PA announcement is activated, but start a temporary recording. When the PA / Emergency PA
announcement is finished the system automatically replays the message into the loudspeaker network in the selected zones
(according to the initiated zone selection).
The temporary recording, or recording facility is selected individually per input during installation or previously in a FAT
situation. Once selected, it will be enabled for all messages inserted through this input. It is not dependant of any special or
additional connections within the system.