_______________________________________________________________________________________________________________________________
European Safety Systems Ltd.
Impress House, Mansell Road, Acton, London W3 7QH
Fax: +44 (0)20 8740 4200
Document No. IS 5001 Issue D 11-09-07
Sheet 1 of 6
1) Introduction
The IS-mA1 minialarm is a second generation ATEX certified
intrinsically safe sounder which produces a loud warning
signal in a hazardous area. Forty-nine first stage alarm
sounds can be selected by internal switches and each one
can be externally changed to a second or third stage alarm
sound. The sounder may be used in all gas groups IIA IIB
and IIC.
2) Description
Fig 1 shows a simplified block diagram of an IS-mA1
minialarm sounder. The device operates immediately power
is applied to the + and
–
terminals which are duplicated to
allow a second sounder to be connected in parallel, or for an
end of line monitoring resistor to be installed. The output tone
is defined by the positions of the six internal switches and this
tone can be changed to a second or third stage alarm tone by
connecting terminals S2 or S3 to 0V. The tone generator is
crystal controlled to ensure that when two sounders
connected to the same power supply are started at the same
time the output tones remain synchronised.
3)
Supply Voltage
The IS-mA1 minialarm sounder has been designed to
operate in a hazardous area from a 24V dc supply via a 28V
93mA resistive ATEX certified Zener barrier or galvanic
isolator. The sounders may be tested or used in safe areas
without a Zener barrier or galvanic isolator, but at supply
voltages above 16V the internal current limit will function and
therefore it is recommended that they are not operated
continuously with a direct supply greater than 16V.
Tone Generator
Tone Selection Switches
Volume Control
IS-mA1 Sounder
_
_
S2
S3
+
+
Fig 1 Simplified block diagram
4)
Intrinsic Safety Certification
4.1 ATEX certificate
The IS-mA1 minialarm sounder complies with the following
standards:-
EN50014 : 1997 + A1 and A2,
EN50020 : 2002
EN50284 : 1999
The EC-Type Examination Certificate SIRA 05ATEX2084X
has been issued by the Notified Body Sira. This confirms
compliance with the European ATEX Directive 94/9/EC for
Group II, Category 1G equipment. The sounder carries the
Community Mark and subject to local codes of practice, may
be installed in any of the EEA member countries. This
instruction sheet describes installations which conform to BS
EN60079:Part14:2003 Electrical Installation in Hazardous
Areas. When designing systems for installation outside the
UK, the local Code of Practice should be consulted.
1)
The certification marking is as follows:
e
2S
european safety systems ltd.
London W3 7QH UK
WARNING:
TO AVOID A POSSIBLE ELECTROSTATIC
CHARGE ONLY CLEAN WITH A DAMP CLOTH
IS-mA1 Sounder
II 1G EEx ia IIC T4 (-40
º
C <=Ta<= +60
°
C)
0518
SIRA 05ATEX2084X
Year / Serial No. 05 / 1MA000001
Ui = 28V Ii = 93mA Pi = 660mW Ci = 0 Li = 0
Te w.r.t. Terminal -
Ui = 28V Ii = 0mA
Terminals S2&S3 w.r.t. Terminal -
2)
The equipment may be used in zones 0, 1 and 2
with flammable gases and vapours with apparatus
groups IIA, IIB & IIC and with temperature classes
T1, T2, T3 and T4.
The IS-mA1 sounder is CE marked for
compliance with the European
Explosive Atmospheres Directive
94/9/EC and the European EMC
Directive 89/336/EEC
II 1G EEx ia IIC T4 (-40
º
C <= Ta <= +60
º
C)
