4
Down
While this button is pushed the
indicator will display the number which
the indicator has been calibrated to
display with a 4mA input. When
released the normal display in
engineering units will return.
Up
While this button is pushed the
indicator will display the number which
the indicator has been calibrated to
display with a 20mA input. When
released the normal display in
engineering units will return.
E
No function in the display mode.
3. INTRINSIC SAFETY CERTIFICATION
3.1 ATEX certificate
The BA324D has been issued with an EC-Type
Examination Certificate number ITS99ATEX2002
by Intertek Testing and Certification Ltd showing
compliance with the European ATEX Directive
94/9/EC for Group II, Category 1, gas and dust
atmospheres, EEx ia IIC. The instrument bears
the Community Mark and, subject to local codes of
practice, may be installed in any of the European
Economic Area (EEA) member countries. ATEX
certificates are also acceptable for installations in
Switzerland.
This manual describes installations in explosive
gas atmospheres which conform with BS
EN60079:Part 14:2003 When designing systems
for installation outside the UK, the local Code of
Practice should be consulted.
For use in the presence of combustible dust,
please refer to Appendix 2 which describes
installations complying with EN 61241-14.
3.2 4/20mA input
In Europe, sources of energy which do not
generate more than 1.5V; 100mA and 25mW are,
for intrinsic safety purposes, considered to be
simple apparatus
(Clause 5.4 of EN50 020:1994).
Although the BA324D indicator does not itself
comply with the requirements for
simple
apparatus
,
the EC-Type Examination Certificate specifies that
under fault conditions the voltage, current and
power at the 4/20mA input terminals 1 and 3 will
not exceed those specified for
simple apparatus
in
Clause 5.4 of EN50020:1994. This
allows the BA324D to be connected into any
intrinsically safe circuit protected by a Zener barrier
or galvanic isolator, providing the output
parameters of the circuit do not exceed:
Uo
=
30V dc
Io
=
200mA
Po
=
0.85W
For this reason the BA324D only has an apparatus
certificate. No system certificate has been issued,
or is required, because the system certificate of the
loop into which the indicator is connected remains
valid. Note: The optional display backlight does
have a system certificate.
The BA324D EC-Type Examination Certificate
specifies that the maximum equivalent capacitance
and inductance between the two 4/20mA input
terminals is:
Ci
= 20nF
Li
= 10µH
To determine the maximum permissible cable
parameters these figures must be subtracted from
the maximum cable capacitance and inductance
permitted by the system certificate of the loop into
which the BA324D is connected.
3.3 Use in explosive gas atmospheres
Zones, gas groups and T rating
The BA324D has been certified EEx ia IIC T5.
When connected to a suitable system the indicator
may be installed in:
Zone 0 explosive gas air mixture
continuously present.
Zone 1 explosive gas air mixture likely
to occur in normal operation.
Zone 2 explosive gas air mixture not
likely to occur, and if it does will
only exist for a short time.
Be used with gases in groups:
Group A propane
Group B ethylene
Group C hydrogen
Having a temperature classification of:
T1
450°C
T2
300°C
T3
200°C
T4
135°C
T5
100°C
