_______________________________________________________________________________________________________________________________
European Safety Systems Ltd.
Impress House, Mansell Road, Acton, London W3 7QH [email protected] Tel: +44 (0)20 8743 8880
www.e2s.com Fax: +44 (0)20 8740 4200
Document No. IS 4501 Issue E 27-11-09
Sheet 3 of 6
intrinsically safe relay or a galvanic isolator, all of which must
have been certified by an EC Notified Body. Only diode
return barriers with a voltage drop of less than 0.9V may be
used. Alternatively, these terminals may be connected
directly to a mechanically activated switch within the
hazardous area.
+ + - -
S2 S3
1 2 3 4 5 6
Input Terminals
Volume
Control
Tone Setting
Switches 1-6
ON
Fig 2 Location of field terminals and controls.
4.5 Other intrinsic safety certifications
Please contact European Safety Systems Ltd. for details of
non-European intrinsic safety approvals.
5)
Installation
IS-A105N sounders should only be installed by trained
competent personnel.
5.1 Mounting
The IS-A105N sounder may be secured to any flat surface
using the two 7mm diameter fixing holes. The enclosure
provides IP66 protection and is suitable for installation in
exterior locations providing it is positioned so that water can
not collect in the horn, and the cable entry is sealed.
5.2 Installation procedure
a. Secure the IS-A105N sounder to a flat surface via the
two 7mm dia fixing holes in the mounting feet.
b. Remove the front of the sounder by unscrewing the
four captive ‘A’ screws and pulling the front away from
the enclosure.
c. Fit a 20mm cable gland or conduit entry into the
untapped hole in the enclosure and connect the field
wiring to the appropriate sounder terminals as shown
in section 6 and fig 2 of this manual. The power supply
ter and - are duplicated so that sounders may
be connected in parallel, or an end of line monitoring
resistor may be fitted.
d. Select the required output tone by positioning the six
switches as shown in Table 1 and Fig 2.
e. Apply power to the sounder and adjust the internal
volume control to provide the required sound level.
f.
Replace the front of the sounder and tighten the four
‘A’ screws.
6)
Electrical System Design For Installation In
Hazardous Areas Using Zener Barriers
6.1 Single stage alarm
If the control switch is in the positive supply, or the power
supply is being turned on and off, only a single channel Zener
barrier is required as shown in Fig 3. This circuit may also be
used if the sounder is being controlled by a mechanically
activated switch on the hazardous area side of the barrier.
Power
Supply
+
0V
Barrier
On/Off
IS-A105N
Sounder
+
-
28V 93mA
Positive
Hazardous Area
Safe Area
Fig 3 Single stage alarm using single channel barrier.
If the control switch must be in the negative supply, the circuit
shown in Fig 4 may be used. Any diode return barrier certified
Ex ia by a EC Notified Body may be used, providing its
voltage drop is less than 0.9V.
Power
Supply
+
0V
Barrier
IS-A105N
Sounder
+
-
28V 93mA
Positive
Hazardous Area
Safe Area
Diode Return
Barrier
On/Off
Fig 4 Single stage alarm using two channel barrier.
6.2 Multi-stage alarm
Connecting terminal S2 to 0V activates the second stage
alarm, and similarly terminal S3 for the third stage alarm. Fig
5 shows how the diode return barriers may be used. If only
two stages of alarm are required the third stage barrier
should be omitted, the 28V 93mA barrier and the single diode
return channel may then be contained in one package.
Power
Supply
+
0V
Barrier
IS-A105N
Sounder
+
-
28V 93mA
Pos itive
H azardous Area
Safe Area
D io de Re turn
Bar rier
2nd Stage
On/Off
D io de Re turn
Bar rier
3rd Stage
S2
S3
Fig 5 Multi stage alarm using Zener barriers.
