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Hazardous Area
IS-mA1M
Sounder
+
S2
S3
-
Fig 6 Multi stage alarm using Zener barriers.
7)
Electrical System Design For Installation In
Hazardous Areas Using Galvanic Isolators
Galvanic isolators do not require a high integrity earth
connection. For small systems where a high integrity earth is
not already available, the use of galvanic isolators often
reduces the overall installation cost and simplifies design.
7.1 Single stage alarm
The IS-mA1M minialarm sounder may be powered by any
galvanic isolator having output parameters within the limits
specified in section 4.3, which has been certified Ex ia by an
EC Notified Body. The sounder may be controlled by turning
the galvanic isolator on and off, or by a mechanically
activated switch on the hazardous area side of the isolator.
Hazardous Area
IS-mA1M
Sounder
+
-
Fig 7 Single stage alarm using galvanic isolator.
7.2 Multi stage alarm
The IS-mA1M sounder second and third stages may be
activated by using Galvanically Isolated Relays that have
output parameters within the limits specified in section 4.4.
which have been certified Ex ia by an EC Notified Body.
_______________________________________________________________________________________________________________________________
European Safety Systems Ltd. Impress House, Mansell Road, Acton, London W3 7QH
Document No. D251-00-051-IS
Safe Area
28V 93mA
Positive
+
Barrier
On/Off
Diode Return
Barrier
Power
2nd Stage
Supply
Diode Return
Barrier
3rd Stage
0V
Safe Area
Galvanic
Isolator
+
-
Power
Issue 1
12-08-2022
Hazardous Area
IS-mA1M
Sounder
+
-
S2
-
Fig 8 Multi stage alarm using galvanic isolated relays
8)
Cable Parameters
The maximum permitted cable parameters are as specified
on the certificate of the Zener barrier or galvanic isolator that
has been selected for the installation. Normally the limits are
not restrictive, but care should be taken not to exceed a
capacitive limit of 83nF for installations when very long cables
are used.
9)
Volume Control
The output level of the IS-mA1M sounder can be set by
adjusting the volume control potentiometer (see Fig 2).
10)
Maintenance
The sounder should be regularly inspected to ensure that it
has not been damaged. Frequency of inspection depends
upon environmental conditions, but initially we recommend
that this should be done annually.
No attempt should be made to repair a faulty ISmA1M
sounder. Suspect sounders must be returned to
European Safety Systems Ltd. or to your local agent for
repair.
11)
Guarantee
Sounders that fail within the guarantee period should be
returned to European safety Systems Ltd. It is helpful if a
brief description of the fault symptoms is provided.
12)
Customer Comments
European Safety Systems Ltd. is always pleased to receive
comments from customers about our products and services.
All communications are acknowledged and whenever
possible, suggestions are implemented.
www.e2s.com
Sheet 5 of 6
Safe Area
Galvanic Isolator
+
-
Power
Galvanic Isolated Relay
Power
Tel: +44 (0)20 8743 8880
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