BEKA BA524D User manual

BA524D
loop-powered
4½ digit field
mounting indicator
Issue: 4
3rd December 2003

1. Description
2. Operation
2.1 Controls
3. Applications
3.1 Transmitter loops
3.2 Remote indication
4. Installation
4.1 Location
4.2 Installation procedure
4.3 EMC
5. Programming and Calibration
5.1 Summary of programmable functions
5.2 Root extractor
5.3 Resolution
5.4 Position of decimal point
5.5 Calibration using an external current
source.
5.6 Calibration using internal references
5.7 Conditioning sub-menu
5.7.1 AC rejection
5.7.2 Calibration of internal
references.
5.8 Function of the Ppush-button
5.9 Security code
5.10 Over and under-range
6. Calibration Examples
6.1 Using an external current source
6.2 Using the internal references
7. Maintenance
7.1 Fault finding during commissioning
7.2 Fault finding after commissioning
7.3 Servicing
7.4 Routine maintenance
7.5 Guarantee
7.6 Customer comments
8. Accessories
8.1 Units of measurement and instrument
identification.
8.2 Alarms
8.2.1 Solid state output
8.2.2 Programming and adjustment
8.2.3 Alarm enable
8.2.4 Setpoint adjustment
8.2.5 Alarm function
8.2.6 Alarm output status
8.2.7 Hysteresis
8.2.8 Alarm delay
8.2.9 Alarm silence time
8.2.10 Access setpoint
8.2.11 Adjusting alarm setpoints from
display mode.
8.3 Lineariser
8.3.1 Calibration using an external
current source.
8.3.2 Calibration using internal
references.
8.4 Tare function
8.5 Display backlight
8.6 External switches
8.7 Pipe mounting kits
8.8 Stem mounting kit
2
CONTENTS
The BA524D is CE marked to show compliance with the European EMC Directive 89/336/EEC

1. DESCRIPTION
The BA524D is a 4½ digit 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 is required.
The BA524D is a third generation instrument
which, although having additional features
including a separate terminal compartment,
remains electrically compatible with the original
BA524 and BA524C.
The main application of the BA524D is to display a
measured variable or control signal in a 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 instrument 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
BA524D. 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.
Fig 1 Simplified block diagram of BA524D
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.
2.1 Controls
The BA524D 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.
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

3. APPLICATIONS
3.1 Transmitter loops
The BA524D indicator may be connected in series
with any 4/20mA current loop that can tolerate the
1.1V drop required to operate the instrument, and
be calibrated to display the measured variable or
control signal in engineering units.
Fig 2 illustrates a typical application in which a
BA524D indicator is connected in series with a
2-wire transmitter.
Fig 2 BA524D in a transmitter loop
Considering the example shown in Fig 2, the sum
of the maximum voltage drops of all the compo-
nents in the loop must be less than the minimum
power supply voltage.
Minimum operating voltage of 2-wire Tx 10.0
Maximum voltage drop caused by controller 5.0
Maximum voltage drop caused by BA524D 1.1
Maximum voltage drop caused by cables 0.4
_____
16.5V
Therefore at 20mA the power supply in this
example must have an output greater than 16.5V
3.2 Remote indication
A BA524D indicator may be driven from any
4/20mA signal to provide remote indication. Fig 3
shows a typical application in which the output from
a gas analyser drives a BA524D. Again it is neces-
sary to ensure that the voltage capability of the
4/20mA gas analyser output is greater than the
sum of voltage drops introduced by the BA524D
and the cable resistance.
Fig 3 Remote indication
4. INSTALLATION
4.1 Location
The BA524D indicator is housed in a robust IP66
glass reinforced polyester (GRP) enclosure incor-
porating an armoured glass window and stainless
steel fittings making it suitable for exterior mount-
ing in most industrial installations, including
off-shore and waste water treatment.
The BA524D is surface mounting, but may be pipe
or stem mounted using the accessory kits
described in sections 8.7 and 8.8 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
BA524D earth terminal is connected to the internal
EMC filters. For maximum radio frequency inter-
ference rejection this terminal should be connected
to a local earth, or to an earthed cable screen. To
prevent circulating currents, cable screens should
only be earthed at one point.
The BA524D enclosure is fitted with a bonding
plate to ensure electrical continuity between the
three conduit / cable entries.
4

4.2 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 8.7
and 8.8
c. Remove the temporary dust seals from the
three cable entries and install the required
glands, conduit fittings or blanking plugs.
Note: the temporary dust seals do not
provide IP66 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.
Fig 4 BA524D installation procedure
4.3 EMC
The BA524D complies with the requirements of the
European EMC Directive 89/336/EEC. For
specified immunity all wiring should be in screened
twisted pairs.
Additional immunity may be obtained by
connecting the BA524D earth terminal to a local
earth, or to an earthed cable screen.
Fig 5 Dimensions and terminal connections
5

5. PROGRAMMING & CALIBRATION
The BA524D 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
5.1 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 5.1 is read
before attempting programming or recalibration.
When the indicator is fitted with alarms, linearisa-
tion 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 8 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 incor-
rect 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 follow-
ing 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 BA524D 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.
5.1 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
detailed 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 5.2
'rESn' Display resolution
Selects the resolution of the least
significant display digit. May be set to
1, 2, 5 or 10 digits.
See section 5.3
'd.P.' Decimal point
Positions the dummy decimal point
between any of the digits or turns it off.
See section 5.4
'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 5.5
6

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 5.6
'Cond' Indicator conditioning
This function provides access to a
sub-menu enabling the mains (line)
frequency 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 5.7
'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 5.7.1
'rEF' Calibration of internal references
The instrument contains two references
representing a 4 and 20mA input.
These enable the BA524D display to be
calibrated without the need for an
external calibrator, or disconnection
from the 4/20mA supply. See SEt
function.
If the SEt or C--P functions are to be
used, the internal references should be
periodically calibrated.
See section 5.7.2
Display Description of function
'C - - P' Function of P push-button
The BA524D may be programmed to
display the input current in milliamps or
as a percentage when the P
push-button is operated.
See section 5.8
'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 5.9
7

5.2 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
5.3 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.
5.4 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.
5.5 Calibration of display 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 Pwill 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 .
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
output from a resistance thermometer transmitter.
5.6 Calibration using internal references: 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 5.7.2
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 been adjusted
press E to return to the 'SPAn' prompt followed by
Eto return to the menu.
8

5.7 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.
5.7.1 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.
5.7.2 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.
To calibrate the references 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.
The accuracy of the internal references, and hence
the display accuracy when using the SEt function,
will depend upon the accuracy of the external
current source. With a maximum span of 19999
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.
5.8 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 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 5.7.2
5.9 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 indica-
tor 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 program-
mable functions can be obtained by moving the
internal security link to the override position. The
security code can then be viewed by selecting
'CodE' from the main menu and pressing P.
9

10

To gain access to the security code link, remove
the instrument control cover, and if fitted unplug
the external switch connector. The security code
override link is located on the inner row of five pins
as shown in Fig 7.
Fig 7 Location of security code override link
5.10 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.
6. CALIBRATION EXAMPLES
The following examples illustrate the two ways in
which a BA524D indicator may be calibrated.
6.1 Using an external current source
The BA524D indicator 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.
11

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 display at 20mA. 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
Following completion of calibration
return to the display mode by pressing
'E'.
6.2 Using the internal references
As in 7.1 the BA524D 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.
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 maximum
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.
12

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.
Again 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 P
push-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
Following completion of calibration
return to the display mode by pressing
'E'.
7. MAINTENANCE
7.1 Fault finding during commissioning
If a BA524D 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
and no volts wiring or is flowing in the loop.
between no power
terminals supply.
1 and 3.
Insufficient Check supply voltage
loop voltage and voltage drops
to operate caused by all
indicator components in the loop.
Indicator Positive The indicator has been
displays 1 over-range incorrectly calibrated &
is trying to display a
number greater than
19999.
Indicator Negative The indicator has been
displays -1 Over-range 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 position.
mode entered. See Fig 7.
13

7.2 Fault finding after commissioning
ENSURE PLANT SAFETY BEFORE
STARTING MAINTENANCE
If a BA524D fails after it has been functioning
correctly, the following table may help to identify
the cause of the failure.
Symptom Cause Solution
No display No power Check that a current
and no volts supply is flowing in the loop.
between
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. Alternatively the
electronic assembly may be exchanged as
described in section 7.3
7.3 Servicing
To simplify servicing all BA524D indicators use a
common display assembly which can be easily
replaced on site. Depending upon the accessories
fitted, one spare display assembly may be used to
repair any BA524D which fails. The exchange may
be made without disconnecting power, the 4/20mA
loop will continue to function but the indicator
voltage drop will increase from 1V to 4V without
the display assembly.
To exchange the display assembly remove the
terminal cover by unscrewing the two 'A' screws
which will reveal two concealed 'D' screws. If the
instrument is fitted with external push-buttons also
unscrew the two 'C' screws securing the buttons
and un-plug the five way connector. Finally
unscrew all four 'D' screws identified in Fig 4 and
carefully lift off the front of the instrument. The
instrument assembly is secured by three Pozi
headed screws which should be removed.
If the instrument is fitted with a backlight or alarms
the fly-leads connecting the accessory boards to
the terminals should be un-plugged. The replace-
ment display assembly may then be installed and
the enclosure reassembled.
If after replacement of the display assembly the
instrument still does not function, it is likely that the
fault is within the protection components on the
terminal assembly. Terminal assemblies may be
exchanged on site providing the replacement
assembly includes terminals for any accessories
fitted i.e. backlight and alarms.
We recommend that faulty instruments and instru-
ment assemblies are returned to BEKA associates
or to our local agent for repair.
7.4 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.
7.5 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.
7.6 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.
14

8. ACCESSORIES
8.1 Units of measurement and instrument
identification
All BA524D indicators are fitted with a blank label
around the liquid crystal display. This label can be
supplied printed with any units of measurement
and tag information specified at the time of
ordering. Alternatively the information may be
added on-site via an embossed strip, dry transfer
or a permanent marker.
To gain access to the display label remove the
terminal cover by unscrewing the two 'A' screws
which will reveal two concealed 'D' screws. If the
instrument is fitted with external push-buttons also
unscrew the two 'C' screws securing the buttons
and un-plug the five way connector. Finally
unscrew the four 'D' screws and carefully lift off the
front of the instrument - see Fig 4. Add the
required legend to the display label, or replace with
a new pre-printed label which is available from
BEKA associates
The BA524D can also be supplied with a blank or
custom engraved stainless steel plate secured by
two screws to the side of the instrument enclosure.
This plate can accommodate:
1 row of 9 alphanumeric characters 10mm high
or 1 row of 11 alphanumeric characters 7mm high
or 2 rows of 18 alphanumeric characters 5mm high.
8.2 Alarms
The BA524D 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. output is in the alarm
condition (open) when the 4/20mA input current is
zero.
WARNING
These alarm outputs should not be used
for critical safety applications such as a
shut down system.
When an alarm is activated, the BA524D 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.
8.2.1 Solid state output
Each alarm has a galvanically isolated single pole
solid state switch output as shown in Fig 9. The
outputs are polarised and current will only flow in
one direction. Terminals 8 and 10 should be
connected to the positive side of the supply.
Ron = 5ohms + 0.6V
Roff = greater than 180k
Note: Because of the series protection diode
some test meters may not detect a closed alarm
output.
Fig 9 Equivalent circuit of each alarm output
15

Figure 10 shows a typical application for the
BA524D indicator with alarms. A solenoid valve is
controlled by one alarm output, while the second
alarm output operates a sounder.
Fig 10 Typical alarm application
8.2.2 Programming and adjustment
When an alarm card is added to a BA524D the
main programme menu is extended as shown in
Fig 11. The additional functions appear between
'Cond' and 'C--P' in the main menu. For simplicity
Fig 11 only shows the additional functions available
on alarm 1, but alarm 2 has identical facilities.
The following table summarises 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 8.2.3
'SP1' Alarm setpoint 1
Adjusts the alarm setpoint. The alarm
is activated when the indicator display
equals the setpoint.
See section 8.2.4
'HI.LO' Alarm function
Defines whether the alarm has a high or
low function
See section 8.2.5
'no.nc' Normally open or normally closed
output
Determines whether the single pole
alarm output is open or closed in the
alarm condition.
See section 8.2.6
'HStr' Hysteresis
Adjusts the alarm hysteresis.
See section 8.2.7
'dELA' Alarm delay time
Adjusts the delay between the display
equalling the setpoint and the alarm
output being activated.
See section 8.2.8
'SIL' Alarm silence time
Defines the time that the alarm output
remains in the non-alarm condition
following acceptance of an alarm.
See section 8.2.9
'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 8.2.10
16

8.2.3 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.
8.2.4 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.
17

8.2.5 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.
8.2.6 Alarm output status: no.nc
This function allows the alarm output to be open or
closed in the alarm condition. When deciding
which is required, care must be taken to ensure
that the alarm output is fail safe. See Fig 8.
CAUTION
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.
8.2.7 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
hysteresis 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.
8.2.8 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.
8.2.9 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.
18

8.2.10 Access Setpoint: AcSP
This function controls a separate menu which
provides direct access to the alarm setpoints when
the indicator is in the display mode. See section
8.2.11 for a full description. An operator may
therefore adjust the alarm setpoints without having
access to the programme and alarm menus.
Further protection is provided by a separate
security code.
This direct access menu is enabled and a separate
security code entered from the 'AcSP' function in
the programme menu as shown in Fig 11. To
change the menu parameters select 'AcSP' from
the programme menu and press Pwhich will
display the enable prompt 'EnbL'. Press Pagain to
reveal if the direct access menu is 'On' or 'OFF'.
The Up or Down buttons will toggle the display
between the two conditions.
If 'OFF' is selected, the operator will not have
access to the setpoints from the display mode.
Return to the 'AcSP' prompt in the main menu by
pressing E twice.
If 'On' is selected, the operator will have direct
access to the alarm setpoints from the display
mode via a separate optional security code. To
define the four digit numerical code press Pto
return to the 'Enbl' prompt followed by the Up or
Down button to select the access code prompt
'AcCd'. Pressing P will reveal the current security
code. Each digit of the code may be changed by
operating the Up and Down push-buttons, and the
Pbutton to move to the next digit. When the
required code has been entered, press Etwice to
return to the 'AcSP' prompt in the Programme
Menu.
Code 0000 will disable the security code allowing
direct access to the setpoints by pressing the P and
Up buttons simultaneously.
New instruments with alarms are supplied with this
function disabled and the security code set to 0000
8.2.11 Adjusting alarm setpoints from the
display mode
Access to the alarm setpoints from the indicator
display mode is obtained by operating the Pand
Up push-buttons simultaneously as shown in Fig
12. If the setpoints are not protected by a security
code the alarm setpoint prompt 'SP1' will be
displayed. If the setpoints are protected by a
security code, 'COdE' will be displayed first.
Pressing P again will enable the alarm security
code to be entered digit by digit using the Up and
Down buttons to change the flashing digit, and the
Ppush-button to move to the next digit. If the
correct code is entered pressing Ewill cause alarm
setpoint prompt 'SP1' to be displayed. Pressing
the Up or Down button will toggle the display
between the two alarm setpoint prompts 'SP1' and
'SP2'.
If an incorrect security code is entered, or a button
is not pressed within ten seconds, the indicator will
automatically return to the display mode.
Fig 12 Setpoint adjustment from the display mode
To adjust an alarm setpoint select 'SP1' or 'SP2'
and press P which will reveal the current setting.
Each digit of the setpoint may be adjusted using
the Up and Down push-buttons, and the P button to
move to the next digit. When the required setpoint
has been entered, pressing E will return the display
to the 'SP1' or 'SP2' prompt from which the other
setpoint may be selected, or the indicator may be
returned to the display mode by pressing Eagain.
Direct access to the alarm setpoints is only
available when the menu is enabled - see section
9.2.10
19

8.3 Lineariser
The indicator can be supplied with a sixteen point
lineariser which may be adjusted to compensate for
almost any non linear variable. For example, a
level signal from a horizontal cylindrical tank may
be linearised by the indicator to display the tank
contents in linear volumetric units.
The addition of linearising software does not affect
the intrinsic safety of the indicator.
Fig 13 shows a typical linearising characteristic.
Up to sixteen break-points may be programmed to
occur at any input current between 4 and 20mA.
The slope between adjacent break-points may be
set anywhere between -1250 and +1250 display
counts per milliamp. Greater slopes may be
programmed, but the indicator performance will be
degraded. A linear characteristic can be obtained
by programming just two points, one at 4mA and
the other at 20mA.
Fig 13 Typical indicator characteristic
The lineariser software does not change the main
programme menu, but the 'CAL' and 'SEt' functions
are extended as shown in Fig 14. As with a
linear indicator, calibration may be performed with
an external calibrator using the 'CAL' function, or
from the internal references using the 'Set'
function.
8.3.1 Calibration using an external current
source
This method allows direct calibration with a current
source, and is preferred when traceability is
required. If the exact system non-linearity is
unknown, this method also allows direct calibration
from the variable to be displayed. e.g. The output
from a level sensor in an irregular tank may be
displayed in linear volumetric units by filling the
tank with known
incremental volumes and calibrating the indicator
to display the sum of the increments at each
break-point.
The number of break-points required should first be
entered using the 'Add' and 'dEL' functions. In
both these functions the indicator initially displays
the current break-point and the total number of
break-points being used. e.g.
5 13
current total number of
break-point break-points
Display Description of function
'Add' Add a break-point
Adds a new break-point before the
displayed break-point. The calibration
of existing break-points is not changed,
but the identification number of all
subsequent break-points is increased by
one.
'dEL' Remove a break-point
Removes the displayed break-point and
joins the preceding break-point to the
following break-point with a straight line.
The identification number of all
subsequent break-points is decreased
by one.
To add a break-point select 'CAL' from the main
menu and press Pto enter the 'Add' function;
press P again to reveal the current and total
number of break-points. Each subsequent
operation of the P push-button will introduce an
additional break-point. When adding a break-point
to a calibrated indicator, the insertion position can
be selected using the Up and Down push-buttons.
The delete break-point function 'dEL' operates in a
similar manner to the 'Add' function described
above.
When the required number of break-points has
been entered, return to the sub-menu by pressing
E. The indicator will display 'Add' or 'dEL'
depending upon the last function used. Each
break-point can now be programmed.
Select 'PtS' from the sub-menu and press Pwhich
will select the first break-point '0 n', where n is the
total number of break-points entered.
20