Edwards Signaling 2400 Series - Manual (Page 16)

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3.2 Indicating Appliance Circuits (IACs)
Two supervised Indicating Appliance Circuits (IACs) operate using compatible 24 VDC (nominal) polarized
signaling appliances. Each circuit is rated at nominal 24 VDC @ 2.5 Amps, with a total of 4.0 Amps
available for both circuits. An IAC may be programmed as either silenceable or non-silenceable. Signal
rate selection is independently programmable for each IAC as shown in Figure 3.3. Refer to the Appendix
for compatible Indicating Appliances.
IACs generate a trouble indication (slow flashing LED) when field wiring is open or shorted. In an open
fault condition, the panel will attempt to energize the signal appliances (i.e., all appliances up to the circuit
break will operate). An IAC with shorted field wiring will NOT operate in the event of an alarm. If an IAC
develops a short during an alarm, the IAC will automatically shut off and continuously monitor the field
wiring. When the fault is cleared, the IAC will re-energize. These actions protect the power supply and
other panel components from damage caused by the short circuit.
Indicating Appliance Circuit, Class A (Style Z) Operation
To convert Class B IAC zones to Class A (Style Z) IAC zones, install a 2400-BPA Class A (Style D/Z)
Converter Module on the base panel. The converter provides alternate paths to the base panel for both
Indicating Appliance Circuits in the event of a single wire break in an IAC.
Figure 3.3 - IAC Signal Rates