Power Supply; Enclosure; Networking - Secutron MR-2900 Installation Manual

1.8 Power Supply

The Power Supply (MR-2905) is rated at 8A unregulated, providing the system with primary DC power. It is
complete with a battery charger rated at 2 A and battery supervision circuitry. The power supply and
battery are located within the control unit back box.
Battery supervision uses true dynamic supervision circuitry to simulate a load condition approximately
every 90 seconds to ensure that the battery is capable of handling the system load requirements on loss of
primary power.
If the battery voltage drops below 19V it is disconnected to protect against damage from a deep discharge.
A second compartment adjacent to the power supply compartment is provided for 120 VAC terminations.
Note: Never disconnect or reconnect the batteries while AC power is off.

1.9 Enclosure

The enclosure for MR-2900 Control Unit consists of a back box complete with power supply, inner door
assembly complete with main control board, and outer door assembly. The back box and door assemblies
are fabricated from 1/16" steel. The outer door includes tempered glass window, hinge, and lock assembly.
The back box provides necessary "knock out" type openings for conduit entry.
The back box dimensions are 14 2" Wide x 27 2" High x 4" Deep. The outer door assembly is 16 7/8"
Wide x 29 2" High x 1 ¼" Deep. The details and dimensions of the enclosure and the MR-2920 Control
Unit with integrated printer are detailed below in section 1.11.

1.10 Networking

Figure 1: Basic Network Communication Flow
The basic MR-2900 Control Unit can be networked to other Control Units and Annunciator Units to provide
additional input circuits, relays, bells and LEDs. Up to 40 units (Control and/or Annunciator) can be
networked together.
The network is a Class A/Style 7 DCLR loop layout (see diagram). Each unit on the network requires the
MR-2910 Network Board. Programming, servicing and testing are done at each individual unit. One
Control Unit is designated, using the downloaded database, the Master Control Unit for the network. The
Master Control Unit displays the Alarm List for the entire network if configured to do so. The Alarm List is
programmable such that events may be archived locally on each individual panel or the archived
collectively at the Master Panel. Please see the Programming Manual for further details.
There are four different MR-2910 boards available:
• MR-2910
• MR-2910-R1
• MR-2910-R2
• MR-2910-R12
Standard communications is for direct wire connections between units. RS-232 communications is for
connection to fiber optic modems only. Refer to the MR-D1010 Installation Instructions (LT-2048) for
information on connecting a fiber-optic network.
6
UNIT #1
P2 P1
Standard Version
Port 1 RS-232, Port 2 Standard
Port 1 Standard, Port 2 RS-232
RS-232 Version
UNIT #2
P2 P1
UNIT #N
P2 P1