6-3
Each of the 3 NACs has two pairs of driven outputs (A+/A-, B+/B-) which operate
together.
NAC B outputs have polarity reversal supervision and expect a 10k EOLR. Each
connected device must have a suitably rated blocking diode.
NAC A outputs have an integral 10kΩ to accommodate Class A (loop) wiring. Class A
wiring is not mandatory under AS 1670.1.
The 3A max rating applies to each NAC, B + A outputs combined. NAC load current
may be read on the LCD.
The Australian SPS has extra decoupling capacitors fitted to the NAC outputs, and cannot
be used to drive the Simplex range of addressable appliances.
NACs may be programmed to be normally on and the terminals used as power supply
outputs. See the SPS Auxiliary Power Wiring section following.
{xe "guidelines for wiring: NACs"}{xe "NACs: guidelines for wiring"}{xe "wiring:
guidelines (NACs)"}{xe "NACs: guidelines for wiring"}
These rules apply to NAC field wiring:
All wiring should be 0.75 mm
2
to 4 mm
2
.
All wiring is supervised and power-limited.
The maximum alarm current is 3A per circuit. The supervisory current is 2mA at
24 VDC.
The nominal voltage rating is 24 VDC, 2V p-p ripple (maximum).
The total available current (Card Power + NAC power + AUX Power outputs)
from the SPS is 9A.
Terminal designations “+” and “-” are for the alarm state of the NAC, not the
supervision/idle state.
Continued on next page
SPS NAC Field Wiring Guidelines{xe "wiring: distances, Class A (NAC)"}{xe
"NACs: wiring distances (Class A)"}{xe "Class A wiring: distances (NAC)"}
Overview
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