5
Be used with gases in groups:
Group A propane
Group B ethylene
Group C hydrogen
Having a temperature classification of:
T1 450
o
C
T2 300
o
C
T3 200
o
C
T4 135
o
C
T5 100
o
C
At ambient temperatures between -40 and +60
o
C.
Note: Operation only specified between -20
o
C and
+60
o
C.
This allows both instruments 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 indicator 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.
3.4 Certification label information
The certification label is fitted in a recess on the
top outer surface of the instrument enclosure. It
shows the ATEX certification information,
instrument serial number, year of manufacture plus
BEKA associates' name and location. Non
European certification information may also be
shown.
4. SYSTEM DESIGN FOR HAZARDOUS
AREAS
4.1 Transmitter loops
BA327C and BA328C indicators may be
connected in series with almost any intrinsically
safe 4/20mA current loop and calibrated to display
the measured variable or control signal in
engineering units. There are two basic design
requirements:
1. The intrinsic safety output parameters of the
4/20mA loop, which are defined by the Zener
barrier or galvanic isolator, must be less
than:
Uo = 30V dc
Io = 200mA
Po = 0.85W
2. The loop must be able to tolerate the
additional 1.1V required to operate the
indicator.
Fig 2 illustrates a typical application in which an
indicator is connected in series with a 2-wire
transmitter protected by a Zener barrier.
Fig 2 BA327C or BA328C in a transmitter loop
4.2 Remote indication
BA327C and BA328C indicators may be driven via
an intrinsically safe interface from a 4/20mA safe
area signal to provide a remote indication within a
hazardous area. The type of interface is not
critical, either a Zener barrier or a galvanic isolator
may be used, providing that Uo, Io and Po are not
exceeded.
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