GAI-Tronics 12579-003 Monitored Relay Module (MRM) - Manual (Page 4)

Pub. 42004-716L2C
Model 12579-003 Monitored Relay Module Page 4 of 16
f:\standard ioms - current release\42004 instr. manuals\42004-716l2c.doc
05/12
Installation Guidelines
1. Notify plant personnel of a system shutdown prior to servicing the unit.
2. Disconnect power before installing or removing the MRM.
Mounting
To install the module into the Snaptrack, slide either the right or left edge of the module into the top
groove on the track. On the opposite side, press firmly on the top and bottom corners of the module until
they snap into the groove. Carefully press from each corner toward the center and simultaneously snap
the edges firmly into place.
Power
After the MRM is installed onto the Snaptrack, 12 V dc power is brought in from the auxiliary power
supply and terminated on TB9 (PWR IN). The positive leg is connected to TB9-1(+) and the return leg is
landed on TB9-2(−). An earth ground is connected to TB9-3 (EGND). TB9 is paralleled with TB10.
TB10 (PWR OUT) may be used to distribute power to additional Snaptrack modules.
N OTES :
 Although power may be daisy-chained between MRMs and other Snaptrack modules, the preferred
method of delivering power to these modules is by providing a dedicated cable run between each
module and the auxiliary power supply.
 The auxiliary power supply return leg must be connected to earth ground for proper operation. The
physical connection should be made at the auxiliary power supply terminals.
 The ground reference for this assembly must be identical to that of the enclosure.
 The MRM does not contain any current-limiting for power. It is recommended that an external fuse
be provided with the appropriate voltage and current ratings. The selected fuse should be of the
slo-blo variety.
Data Communication Line
Terminal blocks TB11 and TB12 are for the page line connection (FSK data communication) from the
PPI card to additional MIM and MRM modules.
FSK Signal Gain
The FSK Signal Gain, R8, adjusts the FSK transmit signal strength. It is set at the factory and should not
be adjusted by the installer.
Relay - Contact Outputs
The MRM contains eight individually configurable relay-contact outputs, allowing it to control field
devices such as beacons. Connections with these field devices are made at connectors TB1 through TB8
of the 69252-001 Power Relay Module.