6
3.4 Remote reset terminals
The BA338C total display may be reset to zero by
connecting the reset terminals 7 and 8 together for
more than one second. These two terminals have
the following input and output safety parameters:
Uo
=
3.8V dc
Io
=
1.6mA dc
Po
=
2.0mW
Ui
=
28V dc
Ii
=
100mA dc
Pi
=
0.7W
The maximum equivalent capacitance and
inductance between them is:
Ci
=
1nF
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 7 and 8.
Alternatively, the BA338C may be programmed so
that the total display is reset to zero when the Up
and
Down push-buttons are operated
simultaneously for more than two seconds. See
6.12
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. Almost any intrinsically safe relay with
certification permitting the contacts to be
connected to equipment in the hazardous area
may be used. A positive diode return Zener barrier
may also be used as shown in Fig 2. The system
certificates list suitable devices and define the
maximum cable parameters.
3.5 Zones, gas groups and T rating
The BA338C 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 BA338C 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 BA338C to be installed in all Zones
and to be used with most common industrial
gases.
WARNING installation in Zone 0
When installed in a Zone 0 potentially
explosive atmosphere requiring apparatus
of Category 1G, the rate totaliser shall be
installed such that even in the event of rare
incidents, an ignition source due to impact
or friction between the aluminium enclosure
at the rear of the instrument mounting panel
and iron/steel is excluded.
3.6 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 and the instrument
serial number. Non European certification
information may also be included.
