4
Addressable Input Circuits
There are two classes of addressable input circuits supported by the Control Unit:
•
"Class A" (Style 6)
- This is a 4 wire circuit supporting addressable detectors and modules. It
requires two input circuits, one for signal out and one for signal return. Up to 99 detectors and up
to 99 modules can be connected to the circuit.
•
"Class B" (Style 4)
- This is a 2 wire circuit supporting addressable detectors and modules. Up to
99 detectors and up to 99 modules can be connected to the circuit.
1.5 Input Circuit Modules
There are five types of Input Circuit Modules. Table 1 circuit classes are supported by each conventional
module. All Input Circuit Modules control eight of the input circuits, one of circuits 1 to 8, 9 to 16 or 17 to 24.
Any of the Input Modules can be used to control circuits 9 to 16, and circuits 17 to 24. Addressable Input
Modules do not physically fit in the location for circuits 1 to 8.
Ground fault conditions occurring on the input circuits are indicated as to the circuit of origin.
Conventional Input Modules
•
Model MR-2928
- supports all seven classes of conventional circuits. Smoke detector circuits are
current limited to 80 mA while all other circuits are current limited to 10 mA.
•
Model MR-2938
- supports only "Class A" 2-wire smoke detectors circuits. All circuits are current
limited to 80 mA.
Table 1: Input Circuit Module Compatibility
Addressable Input Modules
•
Model MR-2929
- supports both of 8 addressable Style 4 (Class B) circuits and 4 addressable
Style 6 (Class A) circuits
•
Model MR-2909
- supports 8 addressable Style 4 (Class B) circuits.
•
Model MR-2919
- supports 4 addressable Style 6 (Class A) circuits.
Note:
Applicable codes and standards as well as good engineering practices must be considered with
regards to the number of addressable devices connected to one addressable circuit.
Isolation
modules (MRI-500X)
should be used whenever more than one fire zone is protected by one
addressable circuit.
Note:
This board does not support 2-wire smoke detectors on a "Class A" circuit.
MR-2928
MR-2938
Class A (Contact)
9
Class B (Contact)
9
Smoke Detector
“Class B” Only
“Class A” Only
Smoke Detector and Contact Device
“Class B” Only
“Class A” Only
Normally Open
9
Normally Closed
9
Dual End-of-Line
9
