900 Series V5.1: Installation Guide, February 2000 13
3.2.4. Sounder circuit controller - IO956
Figure 8: Wiring diagram for sounder circuit controller
To install a sounder circuit controller:
1. Mount the unit as required. Ensure that the earth continuity is maintained.
2. Connect the communication line to the L1 and L2 inputs. The inputs are polarity
insensitive, but it is recommended that L1 is negative for consistency.
3. Connect the local supply (9 V – 32 VDC) to the supply ‘V ex+’ and ‘V ex-‘ terminals. A
1.25 A fuse is fitted on the PCB in the supply line.
4. Connect the sounder loop to sounder ‘Sounder +’ and ‘Sounder –‘. The loop requires
a 10 kOhm, 0.33 Watt end-of-line resistor. These terminals are monitored for open
circuit and short circuit in the sounder wiring. Each sounder must be connected in
series with a polarising diode, if this is not pre-fitted in the unit.
5. Connect the fault inputs to the contacts from the local power supply as shown in the
Figure 8. If the fault input is not used, link fault ‘COM’ to fault ‘N/C’ as shown in the
figure using a wire link.
Do not connect the local supply directly to the fault supply inputs.
-
To fault monitor the local supply, either:
Normally closed voltage-free fault output contacts across ‘COM’ and ‘N/C’
or
Normally energised voltage-free fault output across ‘COM’ and ‘N/O’ with a
wire link across ‘COM’ and ‘N/C’
* L1 and L2 are polarity insensitive but it is recommended to keep L1
negative for consistency
Series 950
loop
N/C
COM
N/O
Vex -
Vex +
L1 (-ve) *
L2 (+ve) *
10 kOhm
EOL
Ç
Æ
À Normally closed fault
contact
Á Fault input not used
(wire link must be
fitted)
 Normally open fault
contact
à Sounders with
polarising diodes
Ä Fault input
Å Fuse
Æ Sounders +
Ç Sounders –
È Local power supply
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