User Guide

2.2.2 Explosive atmosphere applications
ToselectaRateTotaliserforahazardousareainstallation,
the Zone or Division in which it is to be installed and
the hazard must be known, together with the required
certicationauthorityi.e.IECEx,ATEXorETL.
The range includes intrinsically safe Ex ia models for
installation in most gas and dust Zones. For installations
in Zone 2 or 22 without the need for Zener barriers or
galvanic isolators, models with non-sparking Ex nA
certicationforgashazardsanddustignitionprotectionby
enclosure Ex tc are included.
Field mounting see Table 1
BA334E 1 input 1G Ex ia Separate terminal
compartment.
BA334G 1 input 1GD Ex ia
BA384E 2 input 1G Ex ia Separate terminal
compartment.
BA384G 2 input 1GD Ex ia
BA334NG 1 input 3GD Ex nA and Ex tc
BA384NG 2 input 3GD Ex nA and Ex tc
Panel mounting see Table 2
BA337E 1 input 96 x 48mm 1G Ex ia
BA338E 1 input 144 x 72mm 1G Ex ia
BA337E-SS 1 input Rugged 105 x 60mm 1GD Ex ia
BA388E 2 input 144 x 72mm 1G Ex ia
BA337NE 1 input Rugged 105 x 60mm 3GD Ex nA
and Ex tc
When selecting a Rate Totaliser for installation in a
hazardousarea,theinstrument’shazardousareacerticate
should be consulted to ensure that the instrument has
approval for the required area, hazard and temperature
range.
2.3 Two input models
The two input Rate Totalisers are primarily intended for
use with two owmeters.  Each Rate Totaliser input is
individually congurable and the instrument can display
eitherinput,orthesumordifferenceofthetwoowrates
and totals.
Thetwoinputmodelsenablethetotalowandowrate
from two sources to be calculated and displayed. If it
is required to add more than two ow sources, multiple
Rate Totalisers can be linked using the instrument’s
synchronous pulse output.
2.4 Operating temperature
All the eld and panel mounting Rate Totalisers except
modelswithan‘E-SS’,‘NG’and‘NE’sufxhaveaspecied
operating temperature of -40°C to +70°C. Between these
temperatures the Rate Totalisers will function normally,
however at temperatures below -20°C the display digits
will gradually change more slowly and contrast will be
reduced. At some temperature below -20° the display will
stop functioning, but totalisation will continue normally and
the instrument will not be damaged.
Modelswithan‘E-SS’,‘NG’and‘NE’sufxhaveamaximum
certicationtemperatureof+60°Cbutperformanceisthe
same as the other models at low temperatures.
3. Rate Totaliser function
All BEKA externally powered pulse input Rate Totalisers
have similar functions, although the number of inputs and
the output options may differ.  Fig 5 shows a simplied
block diagram of a one input instrument.
All models can accept pulses from a wide variety of
owmeter transducers or outputs.   To enable a Rate
Totaliser to count pulses from transducers such as a
switch contact, open collector transistor or a two wire
proximity detector, the transducer has to be powered
whichisachievedbyttinganexternallinkbetweentwoof
theRateTotaliser’seldterminals.
1
2
3
4
5
6
RS1
RS2
Power
supply
A4
A3
A2
A1
Alarm
2
Alarm
1
+
+
Optional
isolated
alarms
C4
C3
C2
C1
+
Optional
isolated
4/20mA
output
Optional
backlight
internally
powered
Processor
Display
+
+
+
Link to
energise
input
Input
Pulse low
Pulse high
Magnetic pick-off
Proximity detector
Switch contact
Open collector
Isolated pulse output is optional on 96x48mm panel mounting models
External
reset
P2
P1
+
Earth
Isolated
pulse
output
Fig5SimplieddiagramofsingleinputRateTotaliser
RateTotaliserscancalculateanddisplaytherateofow
and the total ow from most pulse output owmeters
including non-linear owmeters such as a turbine meter
operatingoverawiderangeofows.Allmodelsinclude
a sixteen segment lineariser which can be congured
to minimise non-linearity errors. Rate Totalisers with
two inputs have separate conguration functions and a
separate lineariser for each input.
All the Rate Totaliser models have separate rate and total
displays as shown in Fig 6 with independent calibration
allowingtherateofowandthetotalowtobedisplayed
indifferentunitsofmeasurement.e.g.rateofowcould
beshowninlitresperhourandthetotalowcouldbein
cubic metres.  The display digit size depends upon the
model as shown below.
Display size
6 digits 8 digits
Field mounting
All models 12mm 18mm
Panel mounting
96 x 48mm 6mm 9mm
144 x 72mm 12mm 18mm
Rugged 105 x 60mm 6mm 9mm
8