NCA Systems
84 PN 15842:K 7/23/2002
APPENDIX U NCA Systems
U.1 Capabilities
ACS annunciators communicate with the control panel on the ACS Mode
interface (TB3 on the NCA’s main circuit board). Annunciators can be
programmed to annunciate the status of addressable devices, software zones,
system control functions or shadowing ACS points mapped to an AM2020/
AFP1010. The NCA supports up to 96 points per annunciator address. The ACS
devices can be programmed as either 64 or 96 points depending on which ACS
series is being used. Up to 32 devices can be driven by the EIA-485
communications output, all addresses combined. Two-way communications can
occur with only one annunciator per address; other devices on the same address
must be configured as “Receive Only”.
U.2 Connecting the EIA-485 Circuit
EIA-485 wiring is connected to TB3 of the NCA (ACS
Mode interface) as shown in the accompanying
illustration. See Section 3.3 “EIA-485 Wiring
Specifications” for details and notes about EIA-485
requirements.
U.3 Providing Power to Annunciators
The annunciator’s power supply is connected to +24V
non-resettable power on TB1 of the NCA; any of the
three positive terminals and three negative terminals
can be used to connect power to the ACS. A typical
configuration is shown in the accompanying
illustration.
The current which can be drawn from these power-
limited terminals depends on which supply is being
used to power the NCA; the annunciators may also be
powered directly from the power supply that is
powering the NCA, using the power-limited non-resettable 24VDC terminal.
(See the NCA Manual for details.)
The power run to the annunciator does not require a Power Supervision Relay.
Loss of power is inherently supervised through a Communications loss. This
24 VDC output is supervised, power-limited, filtered, and non-resettable.
+
-
acsNCAeia.cdr
TB3 on NCA
acsNCApwr.cdr
TB1 on NCA
+
+
+
+
--
-
-
+24V POWER COMMON
EARTH
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