BEKA BA327C User manual

BA327C & BA328C
intrinsically safe
loop-powered
4½ digit panel
mounting indicators
issue 11
Issue: 11
3rd November 2009

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 Example
7.1 Using an external calibrator
7.2 Using the internal calibrator
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 Scale card
9.2 Tag strip
9.3 Alarms
9.3.1 Solid state output
9.3.2 Intrinsic safety
9.3.3 Programming and
adjustment.
9.3.4 Alarm enable
9.3.5 Setpoint adjustment
9.3.6 Alarm function
9.3.7 Alarm output status
9.3.8 Hysteresis
9.3.9 Alarm delay
9.3.10 Alarm silence time
9.3.11 Access setpoint
9.3.12 Adjusting alarm setpoints
from display mode.
9.4 Lineariser
9.4.1 Calibration using an external
source.
9.4.2 Calibration using internal
reference.
9.5 Tare function
9.6 Display backlight
9.6.1 Separately powered backlight
9.6.2 Loop powered backlight
Appendix 1 FM & cFM Approval for Installation in
USA and Canada.
Appendix 2 IECEx Certification
The BA327C & BA328C are CE marked to show compliance with the European Explosive
Atmospheres Directive 94/9/EC and the European EMC Directive 2004/108/EC
CONTENTS

3
1. DESCRIPTION
The BA327C and BA328C are 4½ digit intrinsically
safe loop powered digital indicators which display
the current flowing in a 4/20mA loop in engineering
units. Both instruments introduce less than a 1.1V
drop which allows them to be installed into almost
any 4/20mA current loop. No additional power
supply or battery is required.
The two indicators are electrically similar, but have
different size displays and enclosures.
Model Display height Bezel size
BA327C 10mm 96 x 48mm
BA328C 20mm 144 x 72mm
The main application of the BA327C and BA328C
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 indicators can be calibrated to display any
variable represented by the 4/20mA current, e.g.
temperature, flow, pressure or level.
The BA327C and BA328C have been certified
intrinsically safe by ITS Testing and Certification
Ltd to the European ATEX Directive 94/9/EC. The
EC-Type Examination certificate specifies that
under fault conditions the voltage, current and
power at the input terminals of each instrument will
not exceed those specified for simple apparatus in
Clause 5.4 of EN50020:1994.
The BA327C and BA328C are also FM and cFM
approved for use in the USA and Canada, these
approvals are described in Appendix 1.
International IECEx certification is described in
Appendix 2.
2. OPERATION
Fig 1 shows a simplified block diagram of both
models. 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 BA327C and
BA328C

4
2.1 Controls
The BA327C and BA328C are controlled and
calibrated via four push-button switches. In the
display mode 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.
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 BA327C and BA328C have been issued with
an EC-Type Examination Certificate number
ITS02ATEX2028 by Notified Body ITS Testing and
Certification Ltd. This confirms compliance with
the European ATEX Directive for Group II,
Category 1G equipment, EEx ia IIC T5. The
instruments bear 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 manuals
describes installations which conform with
EN60079:Part 14. When designing systems for
installation outside the UK th local Code of
Practice should be consulted.
3.2 4/20mA input
In Europe, sources of energy which do not
generate more than 1.5V; 100mA, or 25mW are for
intrinsic safety purposes considered to be simple
apparatus.
Although the BA327C and BA328C indicators do
not themselves 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 & 3 will not exceed those specified for
simple apparatus. This allows the BA327C and
BA328C to be connected into any intrinsically safe
circuit protected by a EEx ia IIC certified Zener
barrier or galvanic isolator providing the output
parameters of the circuit do not exceed:
Uo = 30V dc
Io = 200mA
Po = 0.85W
The EC-Type Examination Certificate specifies that
the maximum equivalent capacitance and
inductance between the two 4/20mA input
terminals 1 and 2 is:
Ci = 20nF
Li = 10µH
To determine the maximum permitted cable
parameters, these figures should be subtracted
from the maximum cable capacitance and
inductance permitted by the certificate for the loop
into which the indicator is installed.
3.3 Zones, gas groups and T rating
The BA327C and BA328C have 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.

5
Be used with gases in groups:
Group A propane
Group B ethylene
Group C hydrogen
Having a temperature classification of:
T1 450oC
T2 300oC
T3 200oC
T4 135oC
T5 100oC
At ambient temperatures between -40 and +60oC.
Note: Operation only specified between -20oC and
+60oC.
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.

6
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. 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. Fig 3
shows the alternative circuits which may be used.
Fig 3 Alternative circuits for remote indication
in a hazardous area

7
5. INSTALLATION
5.1 Location
BA327C and BA328C indicators are housed in
robust aluminium enclosures with polyester front
panels and Noryl bezels. The front of both
instruments have IP65 protection, and a gasket
seals the joint between the instrument enclosure
and the panel. The indicators may be installed in
any panel providing the environmental limits shown
in the specification are not exceeded.
Figs 4A and 4B show the overall dimensions of
each instrument and the required panel cut-out
dimensions. To achieve an IP65 seal between the
instrument enclosure and the instrument panel the
smaller tolerance aperture must be used, and the
BA328C must be secured with four mounting clips.
Fig 4A BA327C dimensions
Fig 4B BA328C dimensions
5.2 Installation Procedure
a. Insert the indicator into the panel aperture
from the front of the panel.
b. Fix two panel mounting clips to opposite
sides of the instrument and tighten until the
indicator is secure as shown in Fig 5. Four
clips are required to achieve an IP65
between a BA328C and the instrument
panel.

8
c. Connect the panel wiring to the rear terminal
block as shown in Fig 4. To simplify
installation, the terminals are removable so
that the panel wiring can be completed
before the instrument is installed.
Fig 5 Fitting panel mounting clips
5.3 EMC
The BA327C and BA328C comply with the
requirements of the European EMC Directive
2004/108/EEC. For specified immunity all wiring
should be in screened twisted pairs, with the
screens earthed within the safe area. The
indicator enclosure may be earthed locally by
putting a tag under one of the rear panel fixing
screws. EMC performance is shown in the
instrument specification and copies of the report
are available from BEKA associates.

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6. PROGRAMMING AND CALIBRATION
The BA327C and BA328C are programmed and
calibrated via four front panel push-buttons. All
the 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 a reference 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 programmable functions in
section 6.1 be read before starting recalibration.
When the indicator is fitted with alarms,
linearisation or a tare function, additional functions
are added to the menu. These accessories 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 non-volatile memory.
All new BA327C and BA328C 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 each of the main
programmable functions and includes a cross
reference to more detailed information. Fig 6
illustrates the location of each function within the
menu.
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
'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 internal references
to be calibrated, and the mains (line)
frequency rejection to be selected.
Because these parameters will alter the
indicator display, they are contained in
a sub-menu to prevent inadvertent
adjustment. See section 6.7

10

11
Display Description of function
'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 4 and 20mA. These
internal references are used when the
indicator display is calibrated without
an external current calibrator, and
when the input current is displayed in
milliamps. See the SEt and C--P
functions. If either of these functions is
to be used, the internal references
should be periodically calibrated.
See section 6.7.2
'C - - P' Function of P push-button
The Ppush-button may be
programmed to display the input
current in milliamps or the input current
as a percentage of the displayed span.
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
6.2 Root extractor: root
This function is primarily intended for use with
differential flowmeters which have a square law
4/20mA output. To activate the square root
extractor select 'root' from the menu and press P
which will reveal if the function is 'On' or 'OFF'. If
the function is set as required, press Eto return to
the menu, or press the Up or Down button to
change the setting, followed by the E button to
return to the main menu.
For reference, the following table shows the output
current from a non-linearised differential flowmeter.
% of full flow Current output mA
2.5 4.01
10.0 4.16
25.0 5.00
50.0 8.00
75.0 13.00
100.0 20.00
6.3 Resolution: rESn
This function defines the resolution of the least
significant display digit. Decreasing the display
resolution can improve the readability of a noisy
signal. Select ''rESn' from the menu and press P
which will reveal the current display resolution. To
change the resolution press the Up or Down button
to select 1, 2, 5 or 10 digits, followed by the E
button to return to the menu.
6.4 Position of the decimal point: d.P.
A dummy decimal point can be positioned between
any of the digits or may be absent. To position
the decimal point select 'd.P.' from the menu and
press P . The decimal point can then be moved or
turned off by pressing the Up or Down push-
button, followed by Eto return to the menu.
6.5 Calibration using an external
current source: CAL
This function enables the zero and span of the
indicator to be adjusted using an external
calibrated current source. When used with an
accurate traceable current source this is the
preferred method of calibration.
To calibrate the indicator select 'CAL' from the
main menu and press P. The indicator will display
'ZErO' which is a request for a 4mA input current.
Adjust the external current calibrator to 4.000mA
and again press P which will reveal the current
zero display. Each digit of the indicator display
can be changed by pressing the Up or Down
buttons. When the first digit is correct pressing P
will transfer control to the next digit. When all the
digits have been adjusted, press Eto enter the
new zero. The indicator will display 'Ent' for a few
seconds while the information is being stored in
memory, and will then return to the 'ZErO' prompt .

12
To adjust the display at 20mA, press the Up button
which will cause the indicator to display 'SPAn'.
Adjust the external current calibrator to 20.000mA
and again press P which will reveal the existing
full scale display. Each digit of the indicator
display can be changed by pressing the Up or
Down buttons. When the first digit is correct
pressing Pwill transfer control to the next digit.
When all the digits have been adjusted press E to
enter the new span. The indicator will display 'Ent'
for a few seconds while the information is being
stored in memory, and will then return to the
'SPAn' prompt. Finally press Eagain to return to
the main menu.
This function may also be used when calibrating a
complete loop from primary element to indicator
display e.g. when the indicator is displaying the
4/20mA output from a resistance thermometer
transmitter.
6.6 Calibration using internal reference:
SEt
This function enables the zero and span of the
indicator to be adjusted without the need for an
accurate external current source, or for
disconnection from the 4/20mA loop.
The accuracy of this method depends upon the
accuracy of the internal references which should
be regularly calibrated as described in section
6.7.2
To calibrate the indicator select 'SEt' from the main
menu and press P. The indicator will display
'ZErO' , pressing Pagain will reveal the current
display at 4mA. Each digit of the indicator display
can be changed by pressing the Up or Down
buttons. When the first digit is correct pressing P
will transfer control to the next digit. When the
least significant digit has been adjusted, press Eto
return to the 'ZErO' prompt which completes the
adjustment.
To adjust the display at 20mA, press the Up button
which will cause the indicator to display 'SPAn'.
pressing P again will reveal the indicator display.
Each digit can be changed by pressing the Up or
Down buttons. When the first digit is correct
pressing Pwill transfer control to the next digit.
When the least significant digit has beenadjusted
press E to
return to the 'SPAn' prompt followed by Eto return
to the menu.
6.7 Conditioning sub-menu: Cond
This sub-menu allows the mains (line) frequency at
which the indicator has maximum ac rejection to
be selected and the two internal references to be
calibrated. These functions are contained in a
sub-menu to minimise the possibility of inadvertent
adjustment. To gain access to the sub-menu
select 'Cond' from the main menu and press P.
The indicator will display 'SurE' to warn that
changing the parameters in the sub-menu will
change the indicator display. Pressing P again will
give access to the sub-menu, or pressing E will
return the indicator to the main menu.
6.7.1 AC rejection: FrE
Caution
If the mains filter frequency is
changed, the indicator display and
internal references (if used) must be
recalibrated.
To provide maximum low frequency rejection the
internal digital filter may be set to operate at 50 or
60Hz to correspond with the local mains (line)
frequency. To change the frequency select 'FrE'
from the Cond sub-menu and press Pwhich will
reveal the current setting. The setting can be
changed by pressing the Up or Down buttons
followed by the Ebutton to return to the sub-menu.
6.7.2 Calibration of internal references:
rEF
The indicator contains two references representing
4 and 20mA. These references are used in the
SEt function which enables the indicator display to
be calibrated without an external current calibrator.
They are also used in the C--P function when the P
push-button is programmed to display the input
current in the display mode. If neither of these
functions is to be used, it is not necessary to
calibrate the internal references.
The accuracy of the internal references, and hence
the display accuracy, will depend upon the
accuracy of the external current source. With a
maximum span of 20000 the indicators have a
display resolution of 0.8µA, we therefore
recommend that the accuracy of the external
current source used for calibration is greater than
0.4µA.

13
To calibrate the references connect a calibrator to
terminals 1 and 3. Select 'rEF' from the sub-menu
and press Pwhich will result in a '0.004A' prompt
being displayed. Adjust the external current
calibrator to 4.000mA and again press P . The
indicator will display 'Ent' when the 4mA reference
has been updated and will then return to the
'.004A' prompt.
To re-calibrate the 20mA internal reference, press
the Up button which will cause the indicator to
display '.020A'. Adjust the external current
calibrator to 20.000mA and again press P . The
indicator will display 'Ent' when the 20mA
reference has been updated and will then return to
the '.020A' prompt. Two operations of the Ebutton
will return the indicator to the main menu.
6.8 Function of the Ppush-button: C - - P
This parameter defines the function of the Ppush-
button when the indicator is in the display mode.
While the button is operated the indicator will
display the input current in milliamps, or the input
current as a percentage of the span.
To check or change the parameter select 'C - -P'
from the main menu and press Pto reveal the
current setting. Pressing the Up or Down button
will toggle the setting between '4-20' the current
display and 'PC' the percentage display. When set
as required press Eto return to the main menu.
Accuracy of the current display depends upon the
accuracy of the internal references which should
be periodically calibrated - see section 6.7.2
6.9 Security code: COdE
The calibration and conditioning of the instrument
may be protected by a four digit security code
which must be entered before access to the
programme menu is granted. New instruments
are programmed with the default security code
0000 which allows unrestricted access to all
programming functions.
To enter a new security code select 'COdE' from
the menu and press P which will cause the
indicator to display the current security code. Each
digit of the code can be changed using the Up and
Down push-buttons, and the Pbutton to move to
the next digit. When the required code has been
entered press E to return to the main menu. The
revised security code will be activated when the
indicator is returned to the operating mode.
If the security code is lost, access to the
programmable functions can be obtained by
moving the internal security link to the override
position. The original security code can then be
viewed by selecting 'CodE' from the main menu
and pressing P.
To gain access to the security code link, remove
the instrument terminal block by gently pulling.
Unscrew the four corner screws securing the rear
panel an lift off the panel which will reveal the link
as shown in Fig 7.
Fig 7 Location of security code override link
6.10 Over and under-range
If the indicator display range is exceeded, the four
least significant digits will be blanked. Under-
range is indicated by '-1' and over-range by '1'.
Under and over-range are also indicated if the
input current falls below approximately 3.5mA or
rises above approximately 21mA.
If the input current falls below 3mA the instrument
initialisation sequence is performed as described
in section 2.

14
7. CALIBRATION EXAMPLES
The following examples illustrate the two ways in
which a BA327C or BA328C indicator may be
calibrated.
7.1 Using an external calibrator
A BA327C is required to display:
-50.0 with a 4mA input
1050.0 with a 20mA input
from a linear transducer. Maximum display
resolution is required, the frequency of the mains
supply is 50Hz and the existing security code is
1209. In the operating mode the indicator is
required to display the input current as a
percentage of span when the Ppush-button is
operated.
Step 1 Connect indicator to calibrator
Connect the indicator to an accurate
external current source. Terminal 1
positive. The indicator will automatically
perform the initialisation routine
described in section 2, and then display
the input current using the existing
calibration information.
Step 2 Enter programming mode
With an input current between 4 and
20mA put the indicator in the
programming mode by simultaneously
pressing P and E. The indicator will
respond by displaying 'COdE'. Press P
to clear this prompt and set the display to
the security code 1209 using the Up,
Down and Ppush-buttons. Pressing E
will enter the code, and after a few
seconds during which the decimal points
will be scrolled, the first parameter 'root'
in the main menu will be displayed.
Step 3 Square root extraction
With 'root' displayed, press Pwhich will
reveal the root extractor status. The root
extractor can be turned on or off by the
Up or Down buttons. Select 'OFF', and
press Eto return to the main menu.
Step 4 Select frequency of max rejection
Scroll though the main menu until 'Cond'
is displayed. Enter the sub-menu by
pressing Ptwice and select the 'FrE'
function. Using the Up or Down buttons
select '50', and then press Etwice to
return to the main menu.
Step 5 Define function of P push-button
Select 'C--P' from the main menu and
press P to reveal the function of the P
button in the display mode. Select
percentage 'PC' and return to the main
menu by pressing E
Note: Because an input current display
in milliamps is not required, it is not
necessary to calibrate the two internal
references.
Step 6 Position dummy decimal point
Scroll though the main menu until 'd.P.'
is displayed and then press P. Using
the Up and Down push-buttons position
the dummy decimal point in front of the
least significant digit.
Press Eto return to the main menu.
Step 7 Calibrate the display
Scroll through the main menu until
'CAL' is displayed. Press P and the
indicator will request a 4mA input by
displaying 'ZErO'. Set the input current
to 4.0000 ± 0.0004mA and press P
again which will reveal the existing zero
display. Using the Up, Down and P
push-buttons enter the required zero
display of -50.0 Press Eto return to
the 'ZErO' prompt.
Press the Up push-button and the
indicator will request a 20mA input by
displaying 'SPAn'. Set the input
current to 20.0000 ± 0.0004mA and
again press Pwhich will reveal the
existing span display. Using the Up,
Down and Ppush-buttons enter the
required display of 1050.0
Press Etwice to return to the main
menu.
Step 8 Return to the display mode
Return to the display mode by pressing
'E'.
7.2 Using the internal calibrator
As in 7.1 the BA327C is required to display:
-50.0 with a 4mA input
1050.0 with a 20mA input
from a linear transducer. Maximum display
resolution is required, the frequency of the mains
supply is 50Hz and the existing security code is
1209. In the operating mode the indicator is
required to display the input current in milliamps
when the Ppush-button is operated.
This example assumes that the internal references
have been routinely calibrated.

15
Step1 Enter the programming mode
With an input current between 4 and
20mA put the indicator in the
programming mode by simultaneously
pressing P and E. The indicator will
respond by displaying 'COdE'. Press P
to clear this prompt and set the display
to the security code 1209 using the Up,
Down and Ppush-buttons. Pressing E
will enter the code, and after a few
seconds during which the decimal
points will be scrolled, the first
parameter 'root' in the main menu will
be displayed.
Step 2 Square root extractor
With 'root' displayed, press Pwhich
will reveal the root extractor status.
The root extractor can be turned on or
off by the Up or Down buttons. Select
'OFF', and press Eto return to the main
menu.
Step 3 Select frequency of max rejection
Scroll though the main menu until
'Cond' is displayed. Enter the sub-
menu by pressing Ptwice and select
the 'FrE' function. Using the Up or
Down buttons select '50', and then
press Etwice to return to the main
menu.
Step 4 Define function of P push-button
Select 'C--P' from the main menu and
press Pto reveal the function of the P
button in the display mode. Select '4-
20' and return to the main menu by
pressing E.
Step 5 Position dummy decimal point
Select 'd.P' from the main menu and
then press P. Using the Up and Down
push-buttons position the dummy
decimal point in front of the least
significant digit.
Press Eto return to the main menu.
Step 6 Calibrate display
With any input current between 4 and
20mA select 'SEt' from the main menu
and press P. The indicator will display
'ZErO' in the sub-menu, press Pto
reveal the existing zero display. Using
the Up, Down and Ppush-buttons enter
the required zero display of -50.0
Press Eto return to the 'ZErO' prompt.
With any input current between 4 and
20mA press the Up push-button and
the indicator will display 'SPAn'. Press
P to reveal the existing span display.
Using the Up, Down and Ppush-
buttons enter the required span display
of 1050.0 Press Eto return to the
'SPAn' prompt. Press Eagain to
return to the main menu.
Step 7 Return to display mode
Return to the display mode by pressing
'E'.

16
8. MAINTENANCE
8.1 Fault finding during commissioning
If a BA327C or BA328C fails to function during
commissioning the following procedure should be
followed:
Symptom Cause Solution
No display Incorrect There should be 1V
wiring. between terminals 1
& 3 with terminal 1
positive.
No display, Incorrect Check that a current
0V between wiring or is flowing in the loop.
terminals 1 no power
and 3. supply.
Insufficient Check supply voltage
loop voltage and voltage drops
to operate caused by all
indicator. components in the
loop.
Indicator Positive The indicator has
displays 1 over-range. been incorrectly
calibrated & is
trying to display a
number greater than
19999.
Indicator Negative The indicator has
displays –1 over-range. been incorrectly
calibrated & is
trying to display a
number less than
-19999.
Unstable 4/20mA input Check loop supply
display has a large voltage.
ripple content.
Unable to Incorrect Enter correct security
enter the security code or fit security
programme code link in override
mode. entered. position. See Fig 7.
8.2 Fault finding after commissioning
ENSURE PLANT SAFETY BEFORE
STARTING MAINTENANCE
Live maintenance is permitted on
intrinsically safe equipment installed in a
hazardous area, but only certified test
equipment should be used unless a gas
clearance certificate is available.
If a BA327C or BA328C fails after it has been
functioning correctly, the following procedure
should be followed:
Symptom Cause Solution
No display, No power Check that current
0V between supply is flowing in the loop.
terminals 1
and 3.
Unstable 4/20mA input Check loop supply
display has a large voltage.
ripple.
Incorrect Digital filter Recalibrate
calibration FrE has been
changed after
indicator was
calibrated.
If this procedure does not reveal the cause of the
fault, it is recommended that the instrument is
replaced. This can be done without disconnecting
power, but while the indicator is disconnected the
4/20mA loop will be open circuit.
8.3 Servicing
All standard BA327C and BA328C indicators are
interchangeable, a single spare assembly may
therefore be used to replace any instrument which
fails.
We recommend that faulty instruments
and instrument assemblies are returned
to BEKA associates or to your local
BEKA agent for repair.
8.4 Routine maintenance
The mechanical condition of the instrument and
electrical calibration should be regularly checked.
The interval between inspections depends upon
environmental conditions. We recommend that
initially instrument calibration should be checked
annually.
8.5 Guarantee
Indicators which fail within the guarantee period
should be returned to BEKA associates or our local
agent. It is helpful if a brief description of the fault
symptoms is provided.
8.6 Customer comments
BEKA associates is always pleased to receive
comments from customers about our products and
services. All communications are acknowledged
and whenever possible, suggestions are
implemented.

17
9. ACCESSORIES
9.1 Scale card
The BA327C and the BA328C have a window on
the right hand side of the display to hold a card
showing the units of measurement e.g. oC, mBar,
RPM. Indicators can be supplied with a printed
scale card showing any units specified at the time
of ordering. If a printed scale card is not
requested, a blank card will be supplied.
Scale cards can easily be marked on site as
follows:
a. Remove the rear terminal block and the rear
panel as shown in Fig 7.
b. Carefully pull the indicator assembly from the
enclosure.
c. Gently pull and then slide the blank scale
card towards the display window until it is
free. Mark the card with the required legend
and replace in the slot.
9.2 Tag strip
Instruments can be supplied with a thermally
printed tag number on the rear panel. This tag
number is not visible from the front of the
instrument after installation.
9.3 Alarms
The BA327C and the BA328C can be supplied
with two solid state single pole alarm outputs which
may be independently programmed as high or low
alarms with normally open or normally closed
outputs. Fig 8 illustrates the conditions available
and shows which are fail safe, i.e. in the alarm
condition the output is open.
WARNING
These alarms outputs should not be
used for critical safety applications such
as an emergency shut down system.
When an alarm is activated the indicator display
alternates between the measured value and an
alarm identification.
Fig 8 Alarm outputs
Programmable functions for each alarm include
adjustable setpoint, hysteresis, alarm delay and
alarm accept.
9.3.1 Solid state output
Each alarm has a galvanically isolated single pole
solid state switch output which is shown in Fig 9.
The output is polarised and current will only flow in
one direction.
Fig 9 Equivalent circuit of each alarm output
9.3.2 Intrinsic safety
Each alarm output is a separate galvanically
isolated solid state switch which has been certified
as simple apparatus. This allows the alarm
terminals 8 & 9 and 10 & 11 to be connected to
any intrinsically safe circuit protected by a Zener
barrier or galvanic isolator providing the output
parameters of the circuit do not exceed:
Uo = 28V dc
Io = 200mA
Po = 0.85W

18

19
The maximum equivalent capacitance and
inductance between each set of alarm terminals is:
Ci = 20nF
Li = 10µH
These figures must be subtracted from the
maximum permitted cable capacitance and
inductance specified by the system certificate of
the circuit connected to the alarm.
Fig 11 Typical alarm application
9.3.3 Programming and adjustment
When an alarm card is added to a BA327C or
BA328C indicator the main programme menu is
extended as shown in Fig 10. The additional
functions appear between Cond and C--P in the
main menu. For simplicity Fig 10 only shows the
additional functions available on alarm 1, but alarm
2 has identical facilities.
The following table summaries each of the alarm
programme functions and includes a cross
reference to more detailed information. Again
only the functions on alarm 1 are listed, but alarm
2 has identical facilities
Summary of programmable alarm functions
Display Description of function
'EnbL Alarm enable
Enables or disables the alarm function
without changing the alarm parameters.
See section 9.3.4
'SP1' Alarm setpoint 1
Adjusts the alarm setpoint. The alarm
is activated when the indicator display
equals the setpoint.
See section 9.3.5
'HI.LO' Alarm function
Defines whether the alarm has a high
or low function
See section 9.3.6
'no.nc' Normally open or normally closed
output
Determines whether the single pole
alarm output is open or closed in the
non-alarm condition.
See section 9.3.7
'HStr' Hysteresis
Adjusts the alarm hysteresis.
See section 9.3.8
'dELA' Alarm delay time
Adjusts the delay between the display
equalling the setpoint and the alarm
output being activated.
See section 9.3.9
'SIL' Alarm silence time
Defines the time that the alarm output
remains in the non-alarm condition
following acceptance of an alarm.
See section 9.3.10
'AcSP' Access setpoint
Sub-menu which enables direct access
to the alarm setpoints from the indicator
display mode, and defines a separate
security code.
See section 9.3.11

20
9.3.4 Alarm enable: EnbL
This function allows the alarm to be enabled or
disabled without altering any of the alarm
parameters. To check or change the function
select 'EnbL' from the alarm menu and press P
which will reveal the current setting. The function
can be changed by pressing the Up or Down
button followed by the Ebutton to return to the
alarm menu.
9.3.5 Setpoint adjustment: SP1 and SP2
The setpoint of each alarm may be positioned
anywhere between -19999 and 19999 providing
this corresponds to an input current between 3.8
and 20.2mA. e.g. If the indicator has been
calibrated to display 0 with 4mA input and 10000
with 20mA input, the two alarm setpoints may be
positioned anywhere between -125 and 10125.
To adjust the setpoint select 'SP1' or 'SP2' from
the alarm menu and press Pwhich will reveal the
existing alarm setpoint. Each digit of the setpoint
can be adjusted using the Up and Down push-
buttons, and the Pbutton to move to the next digit.
When the required setpoint has been entered
press E to return to the alarm menu.
9.3.6 Alarm function: HI.LO
Each alarm can be conditioned as a high or low
alarm. To check or change the alarm function
select 'HI.LO' from the alarm menu and press Pto
reveal the current setting. The function can be
changed by pressing the Up or Down buttons
followed by the Ebutton to return to the alarm
menu.
9.3.7 Alarm output status: no.nc
This function allows the alarm output to be open or
to be closed in the non-alarm condition. When
deciding which is required, care must be taken to
ensure that the alarm output is fail safe. See Fig 8.
‘no’ Alarm output open in non-alarm condition
‘nc’ Alarm output closed in non-alarm condition
WARNING
When the 4/20mA supply is removed
both alarm outputs will open irrespective
of conditioning. Therefore for fail safe
operation both alarm outputs should be
programmed to be open in the alarm
condition.
To check or change the alarm output status select
'no.nc' from the alarm menu and press Preveal the
current setting. The function can be changed by
pressing the Up or Down button followed by the E
button to return to the alarm menu.
9.3.8 Hysteresis: HStr
During programming hysteresis is shown in the
units the indicator has been calibrated to display.
To adjust the hysteresis select 'HStr' from the
alarm menu and press Pwhich will reveal the
existing figure. Each digit can be adjusted using
the Up and Down push-buttons, and the Pbutton
to move to the next digit. When the required
hystersis has been entered press E to return to the
alarm menu.
e.g. An indicator calibrated to display 0 to 10000,
with a high alarm set at 9000 and hysteresis of 200
will perform as follows:
High alarm will be activated when display
equals or exceeds 9000, but will not reset
until the display falls below 8800.
9.3.9 Alarm delay: dELA
This function enables activation of the alarm output
to be delayed for a fixed time following the alarm
condition occurring. The delay can be
programmed in 1 second increments up to 3600
seconds. If a delay is not required zero should be
entered. To adjust the delay select 'dELA' from the
alarm menu and press Pwhich will reveal the
existing delay. Each digit of the delay can be
adjusted using the Up and Down push-buttons,
and the Pbutton to move to the next digit. When
the required delay has been entered press E to
return to the alarm menu.
9.3.10 Alarm silence time: SIL
This function is primarily intended for use in small
installations where the alarm output directly
operates an annunciator such as a sounder.
When the alarm silence time is set to any figure
other than zero, the Ppush-button becomes an
alarm accept button. After an alarm has occurred,
operating the Pbutton will cause the alarm output
to revert to the non-alarm condition for the
programmed alarm silence time. The display will
continue to indicate an alarm after it has been
accepted and silenced. The alarm silence time
may be adjusted between 0 and 3600 seconds in 1
second increments.
To adjust the alarm silence time select 'SIL' from
the alarm menu and press Pwhich will reveal the
existing time. Each digit can be adjusted using the
Up and Down push-buttons, and the Pbutton to
move to the next digit. When the required time has
been entered press E to return to the alarm menu.