GAI-Tronics 379-002 Monitored RElay Module (MRM) Stations - Manual (Page 10)

Pub. 42004-491A
Model 379-002 Monitored Relay Module Station Page 10 of 13
f:\standard ioms - current release\42004 instr. manuals\42004-491a.doc
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CAUTION
If ac-powered signaling devices are being used on an output loop configured for Mode 4 (Figure 8),
observe the following limitations necessary for reliable operation for the loop monitoring feature:
 The dc-resistance measured across the loop (with both end-of-line device and the MRM
removed from the loop must be at least 100 k

 Do NOT use blocking diodes in this loop.
Figure 8. IAC Line Supervision – AC-Powered Beacons