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Installation Input Circuits
20 MS-2/MS-4 PN 51512:E 01/18/05
2.3 Input Circuits
The MS-2 has two IDCs (Initiating Device Circuits) and the MS-4 has four IDCs. Each
circuit is compatible with System Sensor’s I
3
smoke detectors which generate a
maintenance signal when the detector becomes dirty and a separate supervisory ‘freeze’
signal when ambient temperature falls below the detector rating. The maximum loop
resistance limit for each IDC is 100 ohms. The field wiring for each zone is supervised
for opens, shorts and ground faults (zero impedance to ground). All conditions are
visually and audibly annunciated.
Each circuit is configured for Style B (Class B) operation and will accept I
3
smoke
detectors, any normally-open contact devices as well as conventional 2-wire or 4-wire,
24 VDC smoke detectors. In addition, Zone 1 (IDC 1) on the MS-2 and Zone 2 (IDC2)
on the MS-4 can be programmed as combination supervisory and waterflow zones.
Refer to the Fire•Lite Device Compatibility Document for a list of compatible devices.
MS-4 Initiating Device Circuits can be converted to Style D (Class A) by installing the
optional Class A Converter module. Refer to "CAC-4 Class A Converter Module
(MS-4 only)" on page 25.
TB1
TB2
TB3
B+ B- B+ B-
NAC 1 NAC
2
+ - + -
Nonreset Reset
B+ B- B+ B-
ZONE 1 ZONE 2
B+ B- B+ B-
ZONE 3 ZONE 4
Figure 2.4 IDC Connections
Class B Initiating Device Circuits (supervised and power-limited)
4.7 KΩ, ½ watt resistor P/N:71252
UL listed
compatible
2-wire smoke
detectors
manual pull stations
heat detectors
Dummy load all
unused circuits - 4.7
KΩ, ½ watt resistor
(P/N: 71245)
Note: Zones 3 & 4
on MS-4 only
ms-4idc.cdr
UL listed Power Supervision Relay
(refer to Device Compatibility Document for list of compatible relays)
Resettable 24 VDC
4-wire smoke
detector power
(500 mA maximum)
UL listed compatible 4-wire smoke detector