Technical Information; General; Main Circuit Board - Secutron MR-2900 Installation Manual

1.0 Technical Information

1.1 General

The MR-2900 Fire Alarm Control Unit provides capability for up to 24 Input Circuits, 8 Polarity Reversing
Bell Circuits, network capabilities (with use of an MR-2910 Network Board) and 4 General Purpose Form
"C" Relays as well as system operated relays for alarm, trouble and supervisory indication. If the MR-2900
is ordered with a printer, it is ordered under the panel number MR-2920.
The Control Unit can be networked to provide additional input circuits, visual zones, bell circuits and relays.
Up to 40 Units (Control and/or Annunciator) can be connected to form the network. The network is a Style
7 (Data Communications Link, Redundant (DCLR)) loop.
All programming is done through the LCD and keypad. Input circuit programming and special features,
day/night mode, etc., are done from an externally generated database, while system parameters are
programmed from the LCD and keypad. For programming information, refer to LT-2011 MR-2900
Programming Manual.
The basic MR-2900 Fire Alarm Control Unit consists of the:
• Main Circuit Board (MR-2931)
• Terminal Board (MR-2936)
• Annunciator Strip (MR-2902)
• Power Supply (MR-2905)
• Door Assembly (MR-2972)
• Back Box (MR-2971)

1.2 Main Circuit Board

The Main Circuit Board (MR-2931) provides system controls and visual indications, and contains the
system processor, programming port, printer port and non-volatile memory for system firmware. Software
is installed on the main board for critical functions such as programmable logic and timing functions and
non-critical functions, such as custom zone and devices messages. All jumpers on the board are for
diagnostic and test purposes. There are 6 LEDs in the middle of the right edge for diagnostic purposes.
The visual display consists of a series of LEDs for common system indication of power, alarm, supervisory,
and trouble. An LED clock display is provided to display real time. The flashing colon of the clock provides
visual indication of system processor operation. The clock also displays dashes if a major error/change
occurs. When this happens, the system requires a Hard reboot. A Hard reboot is done by pressing and
releasing the button inside the top of the inner door assembly.
The Circuit Board has an 80-character alphanumeric LCD. It provides descriptions for inputs, display of
archived events, first/last device in alarm, custom messages, etc. The keypad is used to scroll through the
display.
There are three connectors on the bottom of the Main Circuit Board, an audio output jack, a 9-pin service
terminal port and a 25-pin printer port. The ports are discussed below. The audio jack produces various
tones for use in walktesting of the system.
MR-2900 Installation Manual
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