BEKA BA324D User manual

BA324D
Intrinsically safe
loop-powered
4½ digit field
mounting indicator
issue 12
Issue: 12
4th March 2014

2
1. Description
2. Operation
2.1 Controls
3. Intrinsic Safety Certification
3.1 ATEX certificate
3.2 4/20mA input
3.3 Zones, gas groups & T rating
3.4 Certification label information
4. System Design for Hazardous Areas
4.1 Transmitter loops
4.2 Remote indication
5. Installation
5.1 Location
5.2 Installation procedure
5.3 EMC
6. Programming and Calibration
6.1 Summary of programmable functions
6.2 Root extractor
6.3 Resolution
6.4 Position of decimal point
6.5 Calibration using an external current
source.
6.6 Calibration using internal references
6.7 Conditioning sub-menu
6.7.1 AC rejection
6.7.2 Calibration of internal
references.
6.8 Function of the Ppush-button
6.9 Security code
6.10 Over and under-range
7. Calibration Examples
7.1 Using an external current source
7.2 Using the internal references
8. Maintenance
8.1 Fault finding during commissioning
8.2 Fault finding after commissioning
8.3 Servicing
8.4 Routine maintenance
8.5 Guarantee
8.6 Customer comments
9. Accessories
9.1 Units of measurement and instrument
identification.
9.2 Alarms
9.2.1 Solid state output
9.2.2 Intrinsic safety
9.2.3 Programming and adjustment
9.2.4 Alarm enable
9.2.5 Setpoint adjustment
9.2.6 Alarm function
9.2.7 Alarm output status
9.2.8 Hysteresis
9.2.9 Alarm delay
9.2.10 Alarm silence time
9.2.11 Access setpoint
9.2.12 Adjusting alarm setpoints from
display mode.
9.3 Lineariser
9.3.1 Calibration using an external
current source.
9.3.2 Calibration using internal
references.
9.4 Tare function
9.5 Display backlight
9.5.1 Separately powered backlight
9.5.2 Loop powered backlight
9.6 External switches
9.7 Pipe mounting kits
Appendix 1
FM approval for use in USA and cFM
Approval for use in Canada
Appendix 2
ATEX dust certification
Appendix 3
IECEx certification
The BA324D is CE marked to show compliance with the European Explosive Atmospheres
Directive 94/9/EC and the European EMC Directive 2004/108/EC
CONTENTS

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1. DESCRIPTION
The BA324D is a 4½ digit intrinsically safe loop
powered digital indicator which displays the current
flowing in a 4/20mA loop in engineering units. The
indicator only introduces a 1.1V drop which allows
it to be installed into almost any 4/20mA current
loop. No additional power supply or battery are
required.
The BA324D is a third generation instrument
incorporating a separate terminal enclosure.
Complying with the European Explosive
Atmospheres Directive ATEX, the instrument has
been certified intrinsically safe for use in explosive
gas and combustible dust atmospheres. ATEX
dust certification is an option - See Appendix 2.
For installation in the USA and Canada, FM and
cFM intrinsic safety and nonincendive certification
are also available. See Appendix 1.
All versions have IECEx certification.
The main application of the BA324D is to display a
measured variable or control signal in a hazardous
process area. The zero and span of the display
are independently adjustable so that the indicator
can be calibrated to display any variable
represented by the 4/20mA current, e.g.
temperature, flow, pressure or level.
The BA324D has been certified intrinsically safe by
ITS to the European ATEX Directive 94/9/EC. The
EC-Type Examination Certificate specifies that
under fault conditions the voltage, current and
power at input terminals 1 and 3 will not exceed
those specified for simple apparatus in Clause 5.4
of EN50020:1994.
The indicator is housed in a robust IP66 glass
reinforced polyester (GRP) enclosure with an
armoured glass window.
2. OPERATION
Fig 1 shows a simplified block diagram of a
BA324D. The 4/20mA input current flows through
resistor R1 and forward biased diode D1. The
voltage developed across D1, which is relatively
constant, is multiplied by a switch mode power
supply and used to power the instrument. The
voltage developed across R1, which is proportional
to the 4/20mA input current, provides the input
signal for the analogue to digital converter.
Each time a 4/20mA current is applied to the
instrument, initialisation is performed. After a short
delay the following display sequence occurs:
-1.8.8.8.8 Display test in which all
segments of the display
are activated for 0.5
seconds.
Blank display For 0.5 seconds.
Decimal points For 3 seconds.
cycled
Input current Using calibration
display in information stored in
engineering instrument memory.
units.
Fig 1 Simplified block diagram of BA324D
2.1 Controls
The BA324D is controlled and calibrated via four
push-button switches which are located behind the
instrument control cover, or as an option on the
instrument cover. In the display mode i.e. when
displaying a variable, these switches have the
following functions:
PWhile this button is pushed the
indicator will display the input current in
mA, or as a percentage of the
instrument span depending upon how
the indicator has been programmed.
When the button is released the normal
display in engineering units will return.
The function of this push-button is
modified when alarms or a tare function
are fitted to the indicator.

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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.
ENo 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

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This allows the BA324D to be installed in all Zones
and to be used with most common industrial
gases.
3.4 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.
4. SYSTEM DESIGN FOR HAZARDOUS
AREAS
4.1 Transmitter loops
A BA324D indicator 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 a
BA324D indicator is connected in series with a 2-
wire transmitter protected by a Zener barrier.
Fig 2 BA324D in a transmitter loop
4.2 Remote indication
A BA324D may be driven from a 4/20mA safe area
signal via an intrinsically safe interface 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 the output parameters of the interface
are : Uo less than 30V dc
Io less than 200mA
Po less than 0.85W
Note: when the hazard is a IIC gas, and two single
channel Zener barriers or a two channel Zener
barrier are used, only one barrier or channel may
be a 28V 300ohm device.
Again it is necessary to ensure that the voltage
capability of the 4/20mA signal is sufficient to drive
the indicator plus the voltage drop introduced by
the intrinsically safe interface. Figs 3A, 3B and 3C
show the alternative circuits which may be used.
If one side of the 4/20mA current loop may be
earthed, a single channel Zener barrier provides
the lowest cost protection. If the 4/20mA signal is
not isolated, then two Zener barriers, a two
channel Zener barrier or a galvanic isolator must
be used.

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Fig 3A Simplest circuit with one side of 4/20mA
current loop connected to earth
Fig 3B Two Zener barrier channels are
required if the 4/20mA current
loop can not be earthed at the
barrier busbar.
Fig 3C Galvanic isolator can be used with any
4/20mA current loop.
5. INSTALLATION
5.1 Location
The BA324D indicator is housed in a robust IP66
glass reinforced polyester (GRP) enclosure
incorporating an armoured glass window and
stainless steel fittings making it suitable for exterior
mounting in most industrial installations, including
off-shore and waste water treatment. Please
consult BEKA associates if high vibration is
anticipated.
The BA324D is surface mounting, but may be pipe
or stem mounted using the accessory kits
described in sections 9.7 and 9.8 of this manual.
The field terminals and the two mounting holes are
located in a separate compartment with a sealed
cover allowing the instrument to be installed
without exposing the display assembly.
Terminals 2 and 4 are internally joined and may be
used for linking the return 4/20mA wire - see Fig 2.
Similarly terminals 5 and 6 are internally joined and
may be used for linking cable screens. The
BA324D earth terminal is connected to the internal
EMC filters. For maximum radio frequency
interference rejection this terminal should be
connected to a local earth, or to a cable screen
which is earthed in the safe area. To prevent
circulating currents, cable screens should only be
earthed in the safe area.
The BA324D enclosure is fitted with a bonding
plate to ensure electrical continuity between the
three conduit / cable entries.
5.2 Installation Procedure
Fig 4 illustrates the instrument installation
procedure.
a. Remove the instrument terminal cover by
unscrewing the two captive 'A' screws.
b. Mount the instrument on a flat surface and
secure with screws or bolts through the two
'B' holes. Alternatively use one of the pipe or
stem mounting kits described in sections 9.7
and 9.8
c. Remove the temporary hole plug and install a
cable gland or conduit fitting with required
ingress protection. If more than one entry is
required, replace one or both IP66 stopping
plugs with a cable gland or conduit fitting
having the required ingress protection.
d. Connect the field wiring to the terminals as
shown in Fig 5.
e. Replace the instrument terminal cover and
evenly tighten the two 'A' screws.

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Fig 4 BA324D installation procedure
5.3 EMC
The BA324D complies with the requirements of the
European EMC Directive 2004/108/EC. For
specified immunity all wiring should be in screened
twisted pairs, with the screens earthed in the safe
area
Additional immunity may be obtained by
connecting the BA324D earth terminal to a local
earth, or to a cable screen which is earthed in the
safe area. If this terminal is not connected,
personal and intrinsic safety will not be degraded.
Fig 5 Dimensions and terminal connections

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6. PROGRAMMING & CALIBRATION
The BA324D is programmed and calibrated via
four push-buttons which are located behind the
instrument control cover. When frequent access
to the push-buttons is required, the indicator can
be supplied with external membrane push-buttons
mounted on the outside of the control cover.
All the programming functions are contained in an
easy to use menu which is shown diagramatically
in Fig 6. Each function is summarised in section
6.1 which includes references to more detailed
information. Although this simple menu driven
system enables most adjustments to be made
without repeated reference to this manual, we
recommend that at least the summary of the
programmable functions in section 6.1 is read
before attempting programming or recalibration.
When the indicator is fitted with alarms,
linearisation or a tare function, the basic menu is
expanded to include functions associated with
these optional features. All the optional functions
are described in section 9 of this manual.
Throughout this manual push-buttons are shown in
italics e.g. P or Up push-button, and legends
displayed by the indicator are shown within
inverted commas e.g. 'CAL' and ' ALr2'.
Access to the programme menu is obtained by
operating the Pand Epush-buttons
simultaneously. If the instrument is not protected
by a security code the first parameter 'root' will be
displayed. If a security code other than the default
code 0000 has already been entered, the indicator
will display 'COdE'. Press Pto clear this prompt
and enter the security code for the instrument
using the Up, Down and Ppush-buttons. If the
correct code has been entered pressing Ewill
cause the first parameter 'root' to be displayed. If
an incorrect code is entered the indicator will
return to the display mode.
Once within the menu the required parameter can
be reached by scrolling through the main menu
using the Up and Down push-buttons as shown in
Fig 6. When returning to the display mode
following recalibration or changes to any
parameters, the indicator will display circulating
decimal points for a few seconds while the new
information is stored in permanent memory.
All new BA324D indicators are supplied calibrated
as requested at the time of ordering. If calibration
is not requested, the indicator will be set to display
0.00 with 4mA input, and 100.00 with 20mA input,
but can easily be re-calibrated on-site.
6.1 Summary of programmable functions
This section summarises all of the programmable
functions and when read in conjunction with Fig 6
provides sufficient information to condition and
calibrate the indicator. A cross-reference to more
information is given for each function.
Display Description of function
'root' Square root extractor
Turns the square root extractor for
linearising the output from differential
flowmeters 'On' or 'OFF'. This function
is omitted when a lineariser is installed.
See section 6.2
'rESn' Display resolution
Selects the resolution of the least
significant display digit. May be set to
1, 2, 5 or 10 digits.
See section 6.3
'd.P.' Decimal point
Positions the dummy decimal point
between any of the digits or turns it off.
See section 6.4
'CAL' Calibration of display using external
current source.
Enables the zero and span of the
indicator to be adjusted using an
external current source such as a
calibrator. Also enables a complete
loop to be calibrated from primary
element to the indicator display.
When used with an accurate traceable
current source this is the preferred
method of calibration.
See section 6.5

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Display Description of function
'SEt' Calibration of display using internal
references.
Enables the zero and span of the
indicator to be adjusted without the
need for an accurate input current or
disconnection from the 4/20mA loop.
See section 6.6
'Cond' Indicator conditioning
This function provides access to a sub-
menu enabling the mains (line)
frequency rejection to be selected and
the internal references to be calibrated.
Because these parameters will alter the
indicator display, they are contained in
a sub-menu to prevent inadvertent
adjustment.
Caution
If the mains filter frequency is
changed, the indicator display
and internal references (if used)
must be recalibrated.
See section 6.7
'FrE' Frequency rejection
Defines the mains (line) frequency at
which the indicator has maximum ac
rejection. 50 or 60Hz may be selected.
This function must be set before the
instrument is calibrated as it affects the
indicator display.
See section 6.7.1
'rEF' Calibration of internal references
The indicator contains two references
representing a 4 and 20mA. input
These enable the BA324D display to
be calibrated without the need for an
external calibrator, or disconnection
from the 4/20mA loop. See the SEt
function.
If the SEt or C--P functions are to be
used, the internal references should be
periodically calibrated.
See section 6.7.2
Display Description of function
'C - - P' Function of P push-button
The BA324D may be programmed to
display the input current in milliamps or
the input current as a percentage when
the Ppush-button is operated.
See section 6.8
'COdE' Security code
Defines a four digit numeric code which
must be entered to gain access to
programmable functions. Default code
0000 disables the security function and
allows unrestricted access to all
programmable functions. See section
6.9

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