Instruction sheet for BR385
Intrinsically safe Sounder
1. INTRODUCTION
The BR385 is a third generation ATEX, IECEx and FM certified
intrinsically safe sounder that produces a loud warning signal in a
hazardous area. Forty nine different 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. For ATEX and IECEx installations
the sounder can be used in all gas groups and may be powered from a
BA386 LED flashing beacon, allowing a combined audible and visual
alarm to be constructed.
2. DESCRIPTION
Fig 1 shows a simplified block diagram of a BR385 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 position 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 the
– terminal of the sounder. The tone generator is crystal controlled to
ensure that when two sounders are started at the same time their output
tones remain synchronised.
3. SUPPLY VOLTAGE
For hazardous area installations, BR385 sounders must be powered from
a certified Zener barrier or galvanic isolator that will supply between 8 and
28V at the + and – terminals of the sounder.
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 the audio output will be reduced. Direct connection
to supplies up to 28V of either polarity will not damage the sounder, but it
is recommended that sounders are not operated continuously with a direct
supply greater than 16V.
Fig 1 Simplified block diagram
4. ATEX INTRINSIC SAFETY CERTIFICATION
4.1 ATEX certificate
The BR385 sounder has been issued with an EU-Type Examination
Certificate 06ATEX2032X. This has been used to confirm compliance
with the European ATEX Directive 2014/34/EU for Group II, Category 1G
equipment. See product Declaration of Conformity for confirmation of
compliance with current harmonised standards.
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 EN 60079-14
Electrical installations design, selection and erection
. When designing
systems for installation outside the UK, the local Code of Practice should
be consulted.
Typical BR385 certification information label
Layout and content may vary
II 1G Ex ia IIC T4 Ga (-40ºC <= Ta <= +60ºC)
BR385 sounders are CE marked to show
compliance with the European Explosive
Atmospheres Directive 2014/34/EU and the
European EMC Directive 2014/30/EU
