5
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 BA354D is connected.
3.3 Reset terminals
The BA354D total display may be reset to zero by
connecting the reset terminals RS1 and RS2
together. These two terminals have the following
output and input safety parameters:
Uo
5V dc
Io
1.3mA dc
Po
1.6mW
Ui
28V dc
Ii
98mA dc
Pi
0.65W
The maximum equivalent capacitance and
inductance between them is:
Ci
1.2nF
Li
0
µ
H
The total display may be reset to zero from within
the hazardous area by any mechanically operated
switch connected directly to terminals RS1 and
RS2. Alternatively, the BA354D may be
programmed so that the total display is reset to
zero when the
Up
and
Down
push-buttons are
operated simultaneously.
To reset the total display from the safe area a
Zener barrier or intrinsically safe relay is required
to transfer the contact closure into the hazardous
area. The BA354D system certificates define
suitable interface devices together with the
maximum permissible cable parameters. Almost
any intrinsically safe relay with certification
permitting the contacts to be connected to
equipment in the hazardous area may be used.
Alternatively, one of the positive diode return Zener
barriers listed in the system certificate may be
used - see Fig 3A.
3.4 Zones, gas groups and T rating
The BA354D has been issued with an EC Type
Examination certificate confirming that it complies
with the requirements for Group II Category 1 G
EEx ia IIC T5 (Tamb –40 to 60
o
C) specified in the
ATEX Directive. When connected to a suitable
system the BA354D 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
At an ambient temperature between –40 and
+60°C.
Note
: the guaranteed operating temperature range
is –20 to +60°C
This allows the BA354D to be installed in all Zones
and to be used with most common industrial
gases.
3.5 Certification Label Information
The certification label is fitted in a recess on the
top outer surface of the enclosure. It shows the
ATEX certification information plus BEKA
associates’ name and location. Non European
certification information may also be included. The
instrument serial number and date of manufacture
are recorded on a separate label inside the
terminal compartment.
