Device Loading And Isolator Power Up - Notifier AM2020 User Manual

Device Loading and Isolator Power Up

Isolator modules are powered from the SLC. The internal relay is a latching-type relay to limit the isolator's power
requirements. The contact will open when power is removed. During power up, the relay contact will close when
the SLC voltage rises above 7 volts. If too many addressable devices are connected to one isolator branch (t-
tap) or segment (loop), the isolator will never reach 7 volts and thus remain open (activated) on power up.
When no relay or sounder bases are used, a maximum load of 25 addressable devices can be connected to an
isolator, or between a pair of isolators and/or isolator bases to insure that the isolators power up correctly. Note
that IPX-751 detectors represent an exception, and only two of these detectors constitute a maximum load, not
25. When relay or sounder bases are used between isolator modules or isolator bases, the maximum number of
addressable devices in between isolators is seven. Note that the same addressable device restrictions apply to
isolator bases.
NOTE
During a short circuit fault condition, the control panel will register a trouble (INVALID REPLY) condition for each device on
the isolated SLC branch or loop segment.
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Installation 15088:J 10/22/99
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