ENGINEER SELECTABLE FUNCTIONS
The NC943B call controller has a number of engineer selectable functions (refer to figure 3
below). This section explains how these functions work and how to set them.
Figure 3 : Rear View of the NC943B Call Controller
(a) Accept the call
In this factory-fitted position, pressing the ‘Call Accept’ button will send a slow
pulsing signal to the overdoor light and reset point. All sounders and LEDs will
remain active until the reset point’s ‘RESET’ button is pressed.
(b) Reset the system
In this position, pressing the ‘Call Accept’ button will cancel the alarm and
return the system to its normal state.
(c) Have no effect
With no link fitted, pressing the ‘Call Accept’ button signal will have no effect.
Note: It is recommended the call controller’s button is set up to ‘Call Accept’
operation, which is the factory setting. ‘Reset’ and ‘no effect’ operations
are outside the scope of BS 8300 and therefore not recommended for use in
accessible toilet alarm installations. However, they may be suitable for use in
other applications subject to the approval of the responsible person(s).
Volt-free relay operation (RLY1)
The call controller includes an on-board volt-free relay with contacts rated
30Vd.c. @ 1A. This relay can be used to switch optional externally powered
devices such as sounders, strobes, or the extra low voltage coils of mains
controlling relays.
When no calls are on the system, the normally closed contact is made. When an alarm signal
is present, the relay switches and the normally open contact is made.
‘Call Accept’ button
operation (link PLK1)
Link PLK1 (supplied) allows the
call controller’s ‘Call Accept’
button to be set up as follows
when an alarm signal is raised:
L
N
Volume
+V
E
S
IG
N
A
L
-V
E
NO
C
N
C
DO NOT
REMOVE
(BATTERY BACKUP
COVER)
Fit to
Enable
battery
PLK2
CONN3
CONN2
VR1
RLY1
Accept
Reset
PLK1
Reset
Reset
Reset
(no link fitted)
Volume
NO
C
NC
CONN3
Fit to
Enable
battery
PLK2
Accept
Accept
Accept
VR1
PLK1
PLK1
PLK1
Reset
Reset
Reset
(no link fitted)
Volume
NO
C
NC
CONN3
Fit to
Enable
battery
PLK2
Accept
Accept
Accept
VR1
PLK1
PLK1
PLK1
Reset
Reset
Reset
(no link fitted)
Volume
NO
C
NC
CONN3
Fit to
Enable
battery
PLK2
Accept
Accept
Accept
VR1
PLK1
PLK1
PLK1
Approved Document No.: DNU0951001 Rev 5 • Page 5 of 8
INSTALLING THE ACCESSIBLE TOILET ALARM SYSTEM
ALWAYS ENSURE MAINS SUPPLY IS ISOLATED BEFORE MAKING ANY CONNECTIONS.
Refer to figure 1 (page 2) for wiring details.
Mains wiring
All mains wiring should be provided in accordance with the current edition of the IEE
Wiring Regs. (BS 7671) and/or other national wiring rules.
The general requirement for the mains supply to the NC943B call controller is fixed wiring,
using three core cable of not less than 1mm
2
. This should be fed from an isolating switched
fused spur, fused at 3A, which is marked appropriately and secure from unauthorised
operation.
Live and neutral should be connected to the call controller’s L and N terminals respectively.
If a plastic back box is used, make the earth connection to the earth terminal at connector
block CONN2. If a metal back box is used, the earth connection must be made to the earth
bonding point on the back box.
Extra low voltage (ELV) wiring
Always segregate ELV wiring from mains wiring.
Three cores of four core stranded burglar alarm cable is ideal for ELV wiring on most
installations with all components requiring a positive, negative and signal connection
(except the ceiling / wall pull which DOES NOT require a positive connection).
Note: The running order of the overdoor light, ceiling / wall pull and reset point can be
changed to suit a specific application and/or to reduce wiring runs.
All wall-mounting devices (excluding pull units) should be mounted onto a back box of
25mm depth. Assess the condition and construction of all mounting surfaces prior to
installation and use suitable screw fixings.
Approved Document No.: DNU0951001 Rev 5 • Page 4 of 8
Reset
Reset
Reset
(no link fitted)
Volume
NO
C
NC
CONN3
Fit to
Enable
battery
PLK2
Accept
Accept
Accept
VR1
PLK1
PLK1
PLK1
