BEKA BA427E-SS User manual

Issue: 5
23rd May 2023
BA427E-SS
intrinsically safe
2-wire 4/20mA
rugged manual set p int
stati n
Issue: 5

1. Descripti n
2. Operati n
2.1 Controls - two handed
2.2 Controls - single handed
2.3 Displays
3. Intrinsic Safety Certificati n
3.1 AT X & UK X gas certification
3.2 Zones, gas groups & T rating
3.3 Special conditions for safe use
3.4 4/20mA output
3.5 Certification label information
4. System Design f r Hazard us Areas
4.1 4/20mA loop using Zener barriers
4.2 4/20mA loop using Galvanic Isolators
4.3 Use in an x e or x p panel enclosure
4.3.1 Use in x e panel enclosure
4.3.2 Use in x p panel enclosure
5. Installati n
5.1 Location
5.2 Installation procedure
5.3 Instrument earthing
5.4 MC
5.5 Scale card
6. C nfigurati n and Calibrati n
6.1 Summary of configuration functions
6.2 Adjustment resolution
6.3 Position of decimal point
6.4 Calibration of display using external
meter.
6.5 Calibration of display using internal
reference.
6.6 High & low current output limits
6.7 Pre-set outputs
6.8 Maximum output rate of change
6.9 Function of ( push button in operating
mode.
6.10 ncoder
6.11 One or two handed operation
6.12 Security code
6.13 Reset to factory defaults
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. Access ries
8.1 Scale card
8.2 Tag information
8.3 Display backlight
8.3.1 Loop powering the backlight
8.3.2 Separately powering the
backlight.
8.4 xternal encoder
8.4.1 Intrinsic safety
8.4.2 System design for
hazardous areas.
8.4.3 B KA BA490 rotary encoder
Appendix 1 Dust certificati n
Appendix 2 IECEx certificati n
22222222222222
The BA427 -SS is C marked to show compliance with the uropean xplosive Atmospheres Directive 2014/34/ U
and the uropean MC Directive 2014/30/ U.
They are also UKCA marked to show compliance with UK statutory requirements quipment and Protective Systems
Intended for Use in Potentially xplosive Atmospheres Regulations UKSI 2016:1107
(as amended) and with the lectromagnetic Compatibility Regulations UKSI 2016:1091 (as amended).
CONTENTS

1. DESCRIPTION
The BA427 -SS is a rugged, intrinsically safe, loop
powered panel mounting Set Point Station which
enables the current flowing in a 4/20mA loop to be
manually adjusted via the front panel push buttons,
or an optional external rotary control. The main
application is the adjustment of a plant parameter,
such as a controller set point or an actuator position,
from within a hazardous process area.
Housed in a rugged stainless steel case, the
intrinsically safe BA427 -SS may be safely installed
in an x e, x p, x n or x t panel enclosure without
invalidating the panel enclosure's certification.
To simplify adjustment the Set Point Station
incorporates a 5 digit display and a 31 segment
bargraph which may be calibrated to show the
4/20mA loop current in any linear engineering units.
An optional factory fitted backlight, which may be
loop or separately powered, enables this display to
be read in all lighting conditions.
The BA427 -SS loop current is adjustable between
3 and 22mA but the range may be restricted if only
limited adjustment is required. In addition to the
output being continuously variable, five pre-set
output currents may be configured and subsequently
selected from the front panel push buttons. To
minimise plant disturbance the maximum output rate
of change may be defined.
The BA427 -SS has AT X and UK X intrinsic
safety certification for use in gas and dust hazardous
areas. Both certificates confirm that the front of the
instrument complies with x e, x p and x t ingress
and impact requirements, which in addition to normal
intrinsically safe applications, allows the BA427 -SS
to be installed in an x e, x p or x t panel
enclosure without invalidating the enclosure's
certification.
For international applications the BA427 -SS has
I C x gas and dust certification which is described
in Appendix 2.
2. OPERATION
This instruction manual describes AT X & UK X
system design and installation for use of the
BA427 -SS in a gas hazardous area. Please refer
to Appendix 1 for details of AT X & UK X dust
certification and to Appendix 2 for I C x certification.
Fig 1 shows a simplified block diagram of the
BA427 -SS manual Set Point Station. The 4/20mA
current flowing in the loop may be manually set at
any value between approximately 3 and 22mA using
the front panel & and * push buttons. Initially the
output current changes slowly, but after the button
has been pressed for five seconds the rate of
change accelerates to allow large changes to be
made quickly. The five pre-set outputs, which are
selectable via the instruments front panel push
buttons, allow the operator to quickly select
frequently used plant set points.
To prevent plant disturbance the maximum rate of
output current change initiated by operating the front
panel push buttons, switching between pre-set
outputs or using an optional external encoder may
be defined.
The output resistance of the BA427 -SS is very
high, within the specified operating voltage range,
the loop current will therefore be unaffected by
changes in the supply voltage.
CAUTION
The BA427 -SS output should not be used for
critical safety applications.
Versatile calibration facilities allow the 5 digit internal
display to show the 4/20mA loop current in linear
engineering units. For example, in an application
where the BA427 -SS is being used to adjust the set
point of a speed controller, the internal indicator may
be calibrated to display the required speed in RPM.
For applications in poorly illuminated areas a factory
fitted green backlight is available which may be loop
or separately powered. When loop powered the
backlight produces background illumination enabling
the display to be read at night or in poor lighting
conditions. No additional power supply, intrinsic
safety interface or field wiring are required, but the
Set Point Station voltage drop is increased. When
separately powered, the backlight is brighter but an
additional intrinsic safety interface and field wiring
are required.
Fig 1 Simplified block diagram of BA427 -SS
3

2.1 C ntr ls - tw handed
The BA427 -SS Set Point Station is controlled and
configured via four front panel push buttons located
below the display. In the operating mode i.e. when
the Set Point Station is controlling the loop current
and the display is showing the output in engineering
units, these push buttons can have two alternative
sets of functions depending upon whether the Set
Point Station has been configured for two or single
handed operation.
Two handed operation is the default configuration
which minimises the possibility of accidental
adjustment of the output current by requiring that the
) button be pressed at the same time as the
& or * button to make an adjustment. This
configuration also prevents the optional external
encoder from adjusting the output current unless the
) button is operated.
) + &Output current slowly decreases. After five
seconds the rate of change accelerates so
that large changes may be made quickly. .
) + *Output current slowly increases. After five
seconds the rate of change accelerates so
that large changes may be made quickly.
)Continuously pushing this button for 5
seconds allows the Set Point Station output
to be entered in engineering units digit by
digit using the & or * push button to
adjust the flashing digit and the ( button
to move control to the next digit. When set
as required, pressing the ) button will
enter the new set point.
(While this button is pushed the
BA427 -SS Set Point Station will display
one of three alternatives depending upon
how the instrument has been configured:
Output current mA with ut bargraph
Output as a % f span
Pre-set utputs in engineering units
The display will flash. While continuing
to press the ( button, operating the
& or * button will show the
identification of the pre-set closest to
the present Set Point Station output,
followed by the pre-set value.
Operating the & or * button will scroll
through the five pre-sets and an Abort
position.
Releasing both buttons will leave the
selected pre-set value or Abort legend
flashing for ten seconds, during which
time operating the ) button will update
the Set Point Station output to the
displayed pre-set value. If the ) button
is not operated during this period, the
Set Point Station output will not be
changed and the original engineering
display will be shown.
&While this button is pushed the Set Point
Station will display the numerical value and
analogue bargraph the Set Point Station
has been calibrated to display with a 4mA*
output. When released the normal display
in engineering units will return.
&While this button is pushed the Set Point
Station will display the numerical value and
analogue bargraph the Set Point Station
has been calibrated to display with a
20mA* input. When released the normal
display in engineering units will return.
* If the Set Point Station display has been
calibrated using the CAL function,
calibration points may not be at 4 and
20mA.
( + &Firmware number followed by version.
( + )Access to configuration menu via optional
security code.
4

2.2 C ntr ls - single handed
The BA427 -SS Set Point Station is controlled and
configured via four front panel push buttons located
below the display. In the operating mode i.e. when
the Set Point Station is controlling the loop current
and the display is showing the output in engineering
units, these push buttons can have two alternative
sets of functions depending upon how the Set Point
Station has been configured.
For single handed operation only the & or * push
button has to be pressed to adjust the output current
as shown below. This configuration also allows the
optional external encoder to adjust the output current
without the ) button being operated:
&Output current slowly decreases. After five
seconds the rate of change accelerates so
that large changes may be made quickly.
*Output current slowly increases. After five
seconds the rate of change accelerates so
that large changes may be made quickly.
)Continuously pushing this button for 5
seconds allows the Set Point Station
output to be entered in engineering units
digit by digit using the & or * push
button to adjust the flashing digit and the
( button to move control to the next digit.
When set as required, pressing the )
button will enter the new set point.
(While this button is pushed the
BA427 -SS Set Point Station will display
one of three alternatives depending upon
how the instrument has been configured:
Output current mA with ut bargraph
Output as a % f span
Pre-set utputs in engineering units
The display will flash. While continuing
to press the ( button, operating the
& or * button will show the
identification of the pre-set closest to
the present Set Point Station output,
followed by the pre-set value.
Operating the & or * button will scroll
through the five pre-sets and an ‘Abort’
position.
Releasing both buttons will leave the
selected pre-set value or ‘Abort’ legend
flashing for ten seconds, during which
time operating the ) button will update
the Set Point Station output to the
displayed pre-set value. If the )
button is not operated during this
period, the Set Point Station output will
not be changed and the original
engineering display will be shown.
( + &Firmware number followed by version.
( + )Access to configuration menu via optional
security code.
2.3 Displays
The BA427 -SS Set Point Station has a 5 digit
display plus a 31 segment bargraph.
The digital display may be calibrated using the CAL or
5Et functions to display the engineering variable
represented by the Set Point Station’s 4/20mA
output, such as temperature, pressure or speed.
The digital display shows the requested Set Point
Station output in engineering units, the digital display
will flash until the Set Point Station output is the
same as the requested output.
The bargraph, which is not adjustable, always shows
the actual Set Point Station output. The bargraph
starts and finishes at the two currents at which the
digital display was calibrated, usually 4 and 20mA.
See sections 6.4 and 6.5.
5

3. INTRINSIC SAFETY CERTIFICATION
All BA427 -SS Set Point Stations have I C x, AT X
and UK X gas and dust intrinsic safety certification.
This section of the instruction manual describes
AT X & UK X gas certification. AT X & UK X dust
and I C x approvals are described in Appendixes 1
and 2.
3.1 ATEX & UKEX gas certificati n
The BA427 -SS has been issued with an U-Type
AT X xamination Certificate and a UK-Type UK X
xamination certificate. The indicator carries both
the U community C mark and the UKCA mark.
Subject to local codes of practice it may be installed
in any of the uropean conomic Area ( A)
member countries and in the UK.
This section of the instruction manual describes
AT X & UK X installations in explosive gas
atmospheres conforming with N 60079-14
Electrical installation design, selection and erection.
When designing systems the local Code of Practice
should be consulted.
3.2 Z nes, gas gr ups and T rating
The BA427 -SS Set Point Station has been certified
x ia IIC T5 Ga. When connected to a suitable
system the Set Point Station 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
In gases that may be used with equipment having a
temperature classification of:
T1 450oC
T2 300oC
T3 200oC
T4 135oC
T5 100oC
At ambient temperatures between:
-40 +60oC When installed in an x e,
x p or x t enclosure.
-40 +70oC When used as an x i
instrument n t in an x e,
x p or x t enclosure.
This allows the BA427 -SS Set Point Station to be
installed in all gas Zones and to be used with most
common industrial gases except carbon disulphide
and ethyl nitrite which have an ignition temperature
of 95°C.
3.3 Special c nditi ns f r safe use
The AT x and UK X intrinsic safety certificates have
an ‘X’ suffix indicating that for some applications
special conditions apply for safe use.
When installed in an Ex e, or Ex p panel
enclosure all connections to the BA427E-SS
must be made by appropriately rated Zener
barriers or gal anic isolators.
This means that when installed in an x e, or x p
panel enclosure the BA427 -SS remains an
intrinsically safe instrument and must comply with
the installation requirements shown in this manual.
The certificate also states:
The front of the BA427E-SS stainless steel
enclosure complies with the impact and
ingress requirements for Ex e, & Ex p type of
protection.
Which means that when correctly installed the
BA427 -SS Set Point Station does not invalidate the
x e, or x p panel enclosure certification.
3.4 4/20mA utput
Input safety parameters for the 4/20mA output,
terminals 1 and 3 are:
Ui = 30V dc
Ii = 200mA
Pi = 0.84W
The equivalent maximum capacitance and
inductance between the two 4/20mA output terminals
1 and 3 are:
Ci = 2.2nF
Li =0.01mH (8µH)
Maximum permitted loop cable parameters can be
calculated by adding these figures to Ci and Li of
other instruments in the loop and subtracting the
totals from the maximum cable capacitance Co and
cable inductance Lo permitted for the Zener barrier,
galvanic isolator or associated apparatus powering
the loop.
6

3.5 Certificati n label inf rmati n
The certification information label is fitted in a recess
on the top outer surface of the instrument enclosure.
It shows the I C x, AT X and UKCA certification
information, instrument serial number, year of
manufacture plus B KA associates name and
location.
BA427 -SS certification label
7

4. SYSTEM DESIGN FOR HAZARDOUS
AREAS
4.1 4/20mA l p using Zener barriers
Fig 2 illustrates a typical application in which a
BA427 -SS Set Point Station mounted in a
hazardous area is being used to adjust the setpoint
of a speed controller located in a safe area. To
enable the negative side of both the speed controller
and the power supply to be connected together and
earthed, a Zener barrier is required in series with
both the outgoing and return wires connected to the
BA427 -SS Set Point Station.
The Zener barrier(s) should be certified with
combined output parameters equal to or less than
the maximum BA427 -SS input safety parameters.
Most Zener barriers are certified x ia IIC allowing
them to be connected to equipment located in any
Zone and to be used with any gas group thus
simplifying selection.
For this application a wide range of devices may be
used. A 28V; 93mA positive polarity device in the
outgoing wire and a diode return barrier in the return
wire are industry standard devices which are
available from most barrier manufactures often
housed in a single package.
The maximum permitted cable parameters are those
specified by the Zener barrier certificate, less the
sum of equivalent input capacitance and inductance
Ci & Li of all the other instruments in the loop, in this
example just the BA427 -SS.
When designing the loop it is necessary to establish
that the maximum voltage drop caused by the Set
Point Station, both Zener barrier channels, the load
(speed controller input) and the cable resistance is
always less than the minimum power supply voltage.
Fig 2 Typical application using barriers
In this example:
Min. operating voltage of BA427 -SS 6.1V
Maximum voltage drop caused by 28V 6.8V
93mA Zener barrier
(340 end-to- end resistance x 20mA)
Maximum voltage drop caused by 1.3V
diode return barrier
Maximum voltage drop caused by 5.0V
speed controller input.
(250 x 20mA)
Maximum voltage drop caused by 0.2V
cable resistance
(10 x 20mA)
______
Total maximum voltage drop 19.4V
The minimum power supply voltage must therefore
be above 19.4V, but below 25.5V which is the
maximum working voltage of a typical 28V Zener
barrier.
If the BA427 -SS Set Point Station is fitted with an
optional backlight and this is loop powered, the
minimum operating voltage of the instrument
increases from 6.1 to 10V. See section 8.3.1
4.2 4/20mA l p using Galvanic Is lat rs
Galvanic isolators, although more expensive than
Zener barriers, they do not require a high integrity
earth connection. For small systems where a high
integrity earth is not already available, the use of
galvanic isolators often reduces the overall
installation cost.
The example described in section 4.1 can be
simplified by the use of a galvanic isolator as shown
in Fig 3.
Fig 3 Typical application using a galvanic isolator
8

Any 4/20mA AT X certified 4/20mA galvanic isolator
with output safety parameters equal to or less than
the maximum BA427 -SS certified input parameters
may be used.
The maximum permitted cable parameters are those
specified on the galvanic isolator certificate, less the
sum of equivalent input capacitance and inductance
Ci & Li of all the other instruments in the loop, in this
example just the BA427 -SS.
When designing the loop it is necessary to ensure
that the supply voltage between terminals 1 & 3 of
the BA427 -SS Set Point Station always exceeds
6.1V which is the minimum operating voltage.
If the BA427 -SS Set Point Station includes an
optional backlight which is loop powered, the
minimum operating voltage of the instrument
increases from 6.1 to 10V. See section 8.3.1
4.3 Use in an Ex e r Ex p panel encl sure
l cated in Z ne 1 r Z ne 2.
The BA427 -SS Set Point Station's AT X
and UK X certification permits the Set Point Station
to be installed in an x e IIC Gb increased safety
panel enclosure located in Zone 1 or 2, or in an x p
IIC Gb pressurised panel enclosure located in a
Zone 1 or 2 hazardous area. The Set Point Station
remains intrinsically safe and must be protected by a
Zener barrier or galvanic isolator as described in
sections 4.1 and 4.2. When correctly installed the
Set Point Station installation does not invalidate the
certification of the x p or x e panel enclosure.
4.3.1 Use in an Ex e panel encl sure
l cated in Z ne 1 r Z ne 2.
Installation of a BA427 -SS Set Point Station in an
x e IIC Gb increased safety panel enclosure does
not invalidate the x e panel's ingress and impact
protection as the front of the Set Point Station
complies with x e impact and ingress requirements.
Although mounted in an x e panel enclosure, the
BA427 -SS Set Point Station remains Group II
Category 1G x ia IIC T5 Ga intrinsically safe
apparatus so must be powered via a Zener barrier or
galvanic isolator as described in section 4.1 and 4.2
of this manual.
Some Zener barriers and galvanic isolators are
certified for mounting within a protective enclosure
located in Zone 2 which may permit them to be
mounted in the same x e enclosure as the BA427 -
SS Set Point Station. Zener barriers and galvanic
isolators are not permitted in x e enclosures located
in Zone 1.
Fig 4 Typical installation in x e panel enclosure
The BA427 -SS Set Point Station terminals, the
wiring to the Set Point Station and the intrinsically
safe interface, if mounted within the enclosure,
should be segregated from all other non-intrinsically
safe wiring and equipment within the panel enclosure
as required by N 60079-11 Equipment protected by
intrinsic safety and N 60079-14 Electrical
installations design, selection and erection. The
x e panel enclosure should be fitted with a warning
label saying 'Do not open when non-intrinsically safe
circuits are energised', alternatively all bare live non-
intrinsically safe parts within the panel enclosure
should have an IP30 cover carrying a warning label
'Do not open when energised'.
The power dissipation within a BA427 -SS Set Point
Station when fitted with an optional backlight which is
separately powered is normally about 320mW. In
the very unlikely event that both circuits fail to the
worst case condition at the same time, the total
maximum power dissipation rises to 1.7W which
could raise the internal temperature of a small
thermally well insulated panel enclosure.
9

4.3.2 Use in an Ex p panel encl sure l cated in
Z ne 1 r Z ne 2.
Installation of a BA427 -SS Set Point Station in an
x p IIC Gb or x p IIC Gc pressurised panel
enclosure does not invalidate the x p panel's
impact and ingress protection as the front of the
BA427 -SS complies with x p impact and ingress
requirements. Although mounted in an x p panel
enclosure, the Set Point Station remains Group II
Category 1G x ia IIC T5 Ga intrinsically safe
apparatus and must therefore be powered via a
Zener barrier or galvanic isolator as described in
section 4.1 and 4.2 of this manual to ensure that the
instrument's front panel push button switches are
nonincendive.
When installed in an x p panel enclosure the four
vents at the rear of BA427 -SS set point station
which are shown in Fig 8 should not be obstructed.
Zener barriers and galvanic isolators may be
installed in the same x p enclosure as the Set
Point Station. All may be mounted in an x px
enclosure installed in Zones 1 or 2, or in an x pz
enclosure installed in Zone 2, both of which have a
non-hazardous interior. Some Zener barriers and
galvanic isolators may have certification permitting
installation within an x py enclosure which has a
Zone 2 interior.
The Set Point Station terminals, the wiring to the Set
Point Station and the intrinsically safe interface, if
mounted within the enclosure, should be segregated
from all other non-intrinsically safe wiring and
equipment within the panel enclosure as required by
N 60079-11 Equipment protected by intrinsic safety
and N 60079-14 Electrical installations design,
selection and erection.
If live maintenance is anticipated, it is recommended
that the x p panel enclosure should be fitted with a
warning label saying 'Do not open when non-
intrinsically safe circuits are energised', alternatively
all bare live non-intrinsically safe parts within the
panel enclosure should have an IP30 cover carrying
a warning label 'Do not open when energised'.
Fig 5 Typical installation in x p panel enclosure
10

5. INSTALLATION
5.1 L cati n
The BA427 -SS Set Point Station has a stainless
steel case with a 10mm thick toughened glass
window. The case provides 7J and the window 4J
front of panel impact protection. The captive silicone
gasket, which seals the joint between the instrument
and the panel enclosure, ensures IP66 front of panel
ingress protection. The rear of the instrument has
IP20 protection.
Although the front of the instrument has IP66
protection, it should be shielded from continuous
direct sunlight and severe weather conditions.
The BA427 -SS Set Point Station may be installed
in any panel enclosure located in Zone 0, 1 or 2,
providing that the operating temperature is between -
40°C and +60°C and the installation complies with
the instrument's certification requirements.
Installation in x e and x p panel enclosures is
described in sections 4.3.1 and 4.3.2.
Fig 6 shows the overall dimensions of the
BA427 -SS together with the recommended panel
enclosure cut-out dimensions.
Fig 6 Dimensions
5.2 Installati n Pr cedure
a. Cut the aperture specified in Fig 6 in the panel
enclosure. nsure that the edges of the
aperture are de-burred.
b. Inspect the instrument's captive gasket and
ensure that it is not damaged before inserting
the Set Point Station into the panel enclosure
aperture.
c. If the enclosure panel is less than 1.0mm thick,
or is non-metallic, an optional B KA stainless
steel support plate should be slid over the rear
of the indicator before the panel clamps are
fitted to evenly distribute the clamping force
and prevent the enclosure panel being
distorted or creeping.
d. Slide a panel clamp into the two grooves at
each corner of the indicator housing with the
M3 stud protruding through the hole at the
rear of the clamp. Fit the stainless steel
spring washer over the stud and secure with
the stainless steel wing nut.
e. venly tighten the four clamps to secure the
instrument. The recommended minimum
tightening torque for each wing nut is 22cNm
(1.95 lbf in).
f. Connect the panel enclosure wiring to the rear
terminal blocks. To simplify installation, the
terminals are removable so that wiring can be
completed before the instrument is installed.
Cables should be mechanically secured to
ensure terminals are not damaged by vibration.
g. Finally, fit a silicone rubber push-on cap to the
end of each M3 threaded rod.
Fig 7 Installation procedure
11

5.3 Instrument earthing
The BA427 -SS Set Point Station has an M4 earth
stud on the rear panel which should be electrically
connected to the panel enclosure in which the
instrument is mounted, or to the plant equipotential
conductor.
5.4 EMC
The BA427 -SS Set Point Station complies with the
uropean MC Directive and with UK statutory
requirements. For specified immunity all wiring
should be in screened twisted pairs, with the screens
earthed in the safe area.
Fig 8 Rear terminals
5.5 Scale card
The Set Point Station's units of measurement are
shown on a printed scale card in a window at the
right hand side of the display. The scale card is
mounted on a flexible strip that is inserted into a slot
at the rear of the instrument as shown in Fig 9. Thus
the scale card can easily be changed without
dismantling the indicator or removing it from the
enclosure in which it is mounted.
New instruments are supplied with a printed scale
card showing the requested units of measurement, if
this information is not supplied when the Set Point
Station is ordered a blank card will be fitted.
A pack of self-adhesive scale cards printed with
common units of measurement is available as an
accessory from B KA associates. Custom printed
scale cards can also be supplied.
To change a scale card, unclip the protruding end of
the flexible strip by gently pushing it upwards and
pulling it out of the enclosure. Peel the existing
scale card from the flexible strip and replace it with a
new printed card, which should be aligned as shown
below. Do not fit a new scale card on top of an
existing card.
Install the new scale card by gently pushing the
flexible strip into the slot at the rear of the indicator,
when it reaches the internal end-stop secure it by
pushing the end of the flexible strip downwards so
that the tapered section is held by the rear panel of
the indicator.
Align the self-adhesive printed
scale card onto the flexible
strip and insert the strip into
the indicator as shown below.
Fig 9 Inserting flexible strip carrying scale card
into slot at the rear of Set Point Station.
12

6. CONFIGURATION AND CALIBRATION
Set Point Stations are configured and calibrated via
the four front panel push buttons. All the
configuration functions are contained in an easy to
use intuitive menu that is shown diagrammatically
in Fig 10.
ach menu function is summarised in section 6.1
and includes a reference to more detailed
information.
Throughout this manual push buttons are shown as
(, ), & or * and the Set Point Station display
legends are shown in a seven segment font as they
appear e.g. CAL and CodE.
Access to the configuration menu is obtained by
operating the ( and ) push buttons
simultaneously. If the Set Point Station security code
is set to the default 0000 the first parameter rE5n will
be displayed. If a security code other than the
default code 0000 has already been entered, the Set
Point Station will display CodE. Pressing the
( button will result in 0000 being displayed with one
digit flashing. To gain access the four digit security
code should be entered using the & and * push
buttons to set the flashing digit and the ( button to
move control to the next digit. When the correct four
digit code has been entered, pressing ) will cause
the first parameter rE5n to be displayed. If the code
is incorrect, or a button is not pressed within twenty
seconds, the Set Point Station will automatically
return to the operating mode.
Once within the configuration menu the required
parameter can be reached by scrolling through the
menu using the & or * push buttons as shown in
Fig 10. When returning to the operating mode
following recalibration or a change to any function,
the Set Point Station will display dAtA followed by
5AVE while the new information is stored in
permanent memory.
All new Set Point Stations are supplied calibrated as
requested at the time of ordering. If calibration is not
requested, instruments will be supplied with the
following default configuration:
Default C nfigurati n
Resolution rE5n 10
Display at 4mA output 2ero 0.00
Display at 20mA output 5PAn 100 . 00
Output current limits H--L 03 . 000 & 22 . 000
Maximum output rate of change 000
( button in operating mode P . Fn PC
Pulses per rev of external encoder EnC 12
One or two handed operation Hnd 2 H
Security access code CodE 0000
Default configuration can easily be changed on-site.
6.1 Summary f c nfigurati n functi ns
This section summarises each of the configuration
functions and includes a cross reference to a more
detailed description. Fig 10 illustrates the location of
each function within the configuration menu.
Display Summary f functi n
rE5n Adjustment res luti n
Defines the adjustment resolution of the
front panel & and * buttons and the
optional external rotary control when
adjusting the output current with the Set
Point Station in the operating mode. May
be set to 1, 10 or 100 least significant
digits of the display.
See section 6.2
dP Decimal p int
Positions a dummy decimal point
between any of the displayed digits or
turns it off.
See section 6.3
CAL and 5Et are alternative ways f
calibrating the Set P int Stati n digital display.
CAL Calibrati n f the digital display using
an external current meter.
Preferred method of calibrating the digital
display which enables the zero and span
of the Set Point Station display to be
calibrated to show the engineering units
represented by the 4/20mA output.
Calibration may be performed at any
output current providing the points are at
least 4mA apart. Requires an accurate
external current meter.
See section 6.4
5Et Calibrati n f digital display using
internal references.
Using the Set Point Station’s internal
reference, this function enables the digital
display to be calibrated to show the
engineering units represented by the
output current at 4mA and 20mA. Unlike
the CAL function, an accurate external
current measuring instrument is not
required and the Set Point Station does
not have to be disconnected from the
loop, but calibration can only be
performed at 4 and 20mA.
See section 6.5
13

Display Summary f functi n
H--L High & l w current utput limits
Defines the lower Lo and upper Hi
4/20mA Set Point Station output current
limits.
See section 6.6
P5Et Pre-set utputs
The values of the five pre-set current
outputs are defined by this function. The
pre-set output currents are identified
5Et1 to 5Et5 and are displayed in
engineering units.
This function only appears in the
configuration menu when P5Et, which
allows pre-set values to be viewed and
selected in the operating mode, is
selected in the P . Fn function.
See section 6.7
rAtE Maximum utput rate f change
nables the maximum rate of change of
the 4/20mA output current to be defined.
Adjustable between approximately 1 and
100 seconds for full scale output travel. 0
disables this rate of change limit.
See section 6.8
P . Fn Functi n f ( push butt n in
perating m de.
The Set Point Station may be configured
to display the output current in milliamps,
the output current as a percentage or to
provide access to the five pre-set outputs
when the ( push button is pressed in
the operating mode.
See section 6.9
Display Summary f functi n
EnC Enc der
In addition to the Set Point Station's
4/20mA output being adjusted by the
front panel push buttons, an external
quadrature encoder may be connected to
provide analogue control. This function
allows the number of pulses per
revolution of the knob to be entered.
See section 6.10
Hnd One r tw handed perati n
Allows the Set Point Station output
current to be adjusted by the front panel
& or * push button and by the optional
external encoder with or without the )
button be pressed at the same time.
See secti n 6.11
CodE Security c de
Defines a four digit numeric code that
must be entered to gain access to the
configuration menu. Default code 0000
disables this security function and allows
unrestricted access to all conditioning
functions.
See section 6.12
r5Et Reset
Returns the Set Point Station
configuration to the default condition. To
prevent accidental use, reset must be
confirmed by entering 5urE before it will
be executed.
See section 6.13
14

15

6.2 Adjustment res luti n: rE5n
This function enables the adjustment resolution of
the front panel & and * buttons and the optional
alternative external rotary control to be defined. One
of three different resolutions may be selected 1, 10
or 100 least significant digits of the Set Point Station
display. If 10 is selected the least significant
displayed digit will always be zero and the second
least significant digit will change when the front panel
) button plus the & or * button are pressed in
the operating mode, or the optional external rotary
control is turned. Similarly, if 100 is selected the
least two significant displayed digits will always be
zero and the third least significant digit will change
when the front panel buttons are operated, or the
optional external rotary control is turned.
To define the adjustment resolution select rE5n from
the configuration menu and press ( which will
reveal the current adjustment resolution. To change
the resolution press the & or * button to select 1,
10 or 100, followed by the ) button to enter the
selection and return to the configuration menu.
N tes:
a. This function does not affect the resolution of
adjustments made within the configuration
menu.
b. If a pre-set output has a finer resolution than the
selected adjustment resolution, the finer
resolution will be used to determine the pre-set
output, but the selected resolution will be
restored when the output is adjusted using the
) button plus the & or * button in the
operating mode.
6.3 P siti n f the decimal p int: dP
A dummy decimal point can be positioned between
any of the displayed digits or it may be absent. To
position the decimal point, select dP from the
configuration menu and press (. The decimal
point can be moved by pressing the & or * push
button. If a decimal point is not required it should be
positioned beyond the most or least significant digit.
When positioned as required press the ) button to
enter the selection and return to the dP prompt in the
configuration menu.
6.4 Calibrati n f the digital display using an
external current meter: CAL
This function is the preferred method of calibrating
the Set Point Station digital display to show the
engineering units represented by the 4/20mA output.
The function enables the Set Point Station output
current to be set at two different values, Zero and
Span, measured by a calibrated external current
meter and the corresponding Set Point Station
display to be entered.
The bargraph is not displayed while using the CAL
function.
Although calibration is normally performed at
4.000mA and 20.000mA, other currents may be used
providing they differ by more than 4mA.
To calibrate the Set Point Station display, select CAL
from the configuration menu and press ( to enter
the 2Ero sub-menu used for calibrating the display at
the lower of the two output currents, usually
4.000mA. Pressing ( again will result in Adj being
displayed which is an invitation to adjust the Set
Point Station output current using the & or * push
button. Pressing either of these buttons will cause
the output current to change, gradually accelerating
as the button is held. Alternatively the external rotary
encoder may be used. When the external current
meter shows the required lower output current e.g.
4.000mA, press ( to reveal the existing Set Point
Station digital display with one digit flashing. The
flashing digit may be adjusted by pressing the & or
* button, when this digit is set as required pressing
( will transfer control to the next digit. When all the
digits have been adjusted, press ) to enter the
setting and return to the 2Ero prompt.
Calibration of the Set Point Station display at the
upper output current is performed in exactly the
same way using the 5PAn sub-menu which may be
selected from the 2ero prompt using the & or *
button.
To obtain a reverse acting display i.e. the Set Point
Station display decreases as the output current
increases, the required display value entered into
2Ero should be greater than that entered into 5PAn.
The & and * buttons on the front of the
instrument always indicate which way the display will
change when the button is pushed.
The bargraph will start at the numerical display
entered for 2Ero calibration and finish at the
numerical display entered for 5Pan calibration,
except for reverse acting calibration when the
bargraph will also be reversed.
N te:
a. If the specified 2Ero and 5PAn output currents
do not differ by 4 or more milliamps, they will not
be stored when the ) button is pressed to
return the Set Point Station to the operating
mode.
6.5 Calibrati n f digital display using
internal reference: 5Et
Using the Set Point Station’s internal reference, this
function enables the digital display to be calibrated to
show the engineering units represented by the
output current at 4mA and 20mA.
16

Unlike the CAL function, an accurate external current
measuring instrument is not required and the Set
Point Station does not have to be disconnected from
the loop, however calibration can only be performed
at 4mA and 20mA. Although not traceable to a
calibrated standard, accuracy is adequate for many
industrial applications.
To calibrate the Set Point Station’s digital display
select 5Et from the configuration menu and press
(. The Set Point Station will display . 000,
pressing ( again will reveal the calibrated display
at 4mA output with one digit flashing. The flashing
digit may be adjusted by pressing the & or *
buttons, when the flashing digit is correct pressing
( will transfer control to the next digit. When all the
digits have been adjusted, press ) to return to the
. 000 prompt.
Calibration of the Set Point Station display at 20mA
output is performed in exactly the same way using
the 20 . 000 sub-menu which may be selected from
the . 000 prompt using the & or * button. When
the display corresponding to a 20mA output has
been entered pressing ) twice will enter the setting
and return to the 5Et prompt in the configuration
menu.
The bargraph is not displayed while using the 5Et
function
To obtain a reverse acting display i.e. the Set Point
Station display decreases as the output current
increases, the required display value entered into
. 000 should be greater than that entered into
20 . 000. The & and * buttons on the front of the
instrument always indicate which way the display will
change when the button is pushed.
The bargraph will start at the numerical display
entered for 4mA output and finish at the numerical
display entered for 20mA output, except for reverse
acting calibration when it will also be reversed.
6.6 High & l w current utput limits: H--L
The BA427 -SS output is normally adjustable
between 3 and 22mA, but may be restricted by this
function if a limited adjustment range is required.
e.g. to prevent a dangerously high and/or low
temperature being selected when used as the set
point input for a temperature controller. When the
Set Point Station’s output current equals the high
limit, oVEr is displayed, similarly undEr is displayed
when the output current equals the low limit.
To restrict the Set Point Station’s output current
range select H--L from the configuration menu and
press (. Using the & or * button select Lo to
adjust the lower current output limit, or Hi to adjust
upper output current limit. Pressing ) will display
the selected output current limit in milliamps with one
digit flashing.
The flashing digit may be adjusted by pressing the
& or * button, when the flashing digit is correct
pressing ( will transfer control to the next digit.
When all the digits have been adjusted press ) to
return to the Lo or Hi prompt followed by ) to enter
the adjustments and return to the H--L prompt in the
configuration menu.
N tes:
a. The Lo limit can not be adjusted to a value
above the present Set Point Station output
current, and the Hi limit can not be adjusted to a
value below the present Set Point Station output
current. The actual Set Point Station output
current should therefore be adjusted to within
the acceptable output range before the Lo and
Hi limits are adjusted.
b. If any of the five pre-set output currents are set
below the Lo limit or above the Hi limit, they will
not be selectable and oVEr or undEr will be
displayed.
6.7 Pre-set utputs: P5Et
Up to five pre-set current outputs may be stored and
recalled from the front panel push buttons which
enables common output currents to be quickly
selected. e.g. frequently used operating
temperatures when a BA427 -SS is used as the set
point input for a temperature controller.
To enter pre-set values select P5Et from the
configuration menu and press ( which will result in
5Et 1, the first pre-set sub-menu being displayed,
pressing ( will then reveal the present value in
engineering units with one digit flashing. The
flashing digit may be adjusted by pressing the
& or * button, when the flashing digit is correct
pressing ( will transfer control to the next digit.
When all the digits have been adjusted, press ) to
return to the 5Et 1 prompt from which any of the
other four pre-sets may be selected via the & or *
button and adjusted in the same way as 5Et 1.
N tes:
a. P5et only appears in the configuration menu
when P5Et is selected in the P . Fn menu which
defines the function of the ( push button in
the operating mode. see section 6.9.
b. Maximum adjustment resolution is always
available for inputting pre-set values and is
used to determine the current output when the
pre-set is selected, irrespective of the
adjustment resolution selected in function rE5n
- see 6.2
c. If, after calibration of the Set Point Station
display, previously entered pre-set values are
outside the revised output current range, when
selected the pre-set value alternating with oVEr
or undEr will be displayed.
17

6.8 Maximum utput rate f change: rAtE
To minimise plant disturbance when the Set Point
Station output current is adjusted, the maximum rate
of change is defined by this function. The maximum
rate is adjustable between approximately 1 and 100
seconds for full scale output travel from 4 to 20mA.
If 0 seconds is selected the function is disabled.
To define the maximum rate of change of the Set
Point Station output select rAtE from the
configuration menu and press ( which will reveal
the present maximum rate of change in seconds with
one digit flashing. The flashing digit may be adjusted
by pressing the & or * buttons, when the flashing
digit is correct pressing ( will transfer control to the
next digit. When all the digits have been adjusted,
press ) to enter the new value and return to the
configuration menu.
When the output rate of change limitation is
functioning, in the operating mode the Set Point
Station digital display will show the requested output
and will flash until the requested output current is
achieved. The bargraph display always shows the
Set Point Station’s actual output.
Pressing the ) button while the output is ramping to
a new requested value will stop the output changing.
6.9 Functi n f the ( push butt n in
perating m de: P . Fn
Using this function the Set Point Station may be
configured to display the output current in milliamps,
the output current as a percentage of the output
range, or to provide access to the five pre-set
outputs when the ( button is pressed in the
operating mode.
To check or change the function of the ( push
button select P . Fn from the configuration menu and
press ( to reveal the present setting. Pressing the
& or * button will scroll the setting between:
PC Output as a percentage of output
range.
-20 Output current in milliamps
P5Et Access to the five pre-set outputs
see 6.7
When set as required, press ) to return to the P . Fn
prompt in the configuration menu.
6.10 Enc der: EnC
For applications requiring the Set Point Station’s
4/20mA output current to be controlled by a rotary
knob, an external three wire quadrature encoder
may be directly connected to terminals 5, 6 and 7.
The B KA BA490 Is a panel mounting encoder that
generates 12 contact pulses per revolution which
complies with the requirements for simple apparatus
and is intended for use with the BA427 -SS. Other
encoders that produce a different number of contact
pulses per revolution may also be used. So that all
external encoders have a similar adjustment
resolution, the EnC function enables the number of
pulses between 6 and 48 per revolution to be
defined.
To enter the number of pulses per revolution that the
external encoder generates, select EnC from the
configuration menu and press ( which will reveal
the existing setting with one digit flashing. The
flashing digit may be adjusted by pressing the
& or * button, when the flashing digit is correct
pressing ( will transfer control to the other digit.
When both digits have been adjusted press ) to
return to the EnC prompt in the configuration menu.
Section 8.4 contains information about the use of an
external rotary encoder.
6.11 One r tw handed perati n: Hnd
This function defines whether the front panel )
button has to be pushed at the same time that the
& or * button is operated, or the optional external
encoder is rotated to adjust the Set Point Station's
output current. Selecting the two handed operation
which requires the ) button to be operated which
minimises the possibility of accidental adjustment.
To check or change the function select Hnd from the
configuration menu and press ( to reveal the
existing setting. Pressing the & or * button will
toggle between the two setting:
2 H Output current can only be adjusted
when the ) button is pressed.
1 H Output current can be adjusted
without pressing the ) button.
When set as required, press ) to return to the Hnd
prompt in the configuration menu.
6.12 Security c de: CodE
Access to the instrument configuration menu may be
protected by a four digit security code which must be
entered to gain access. New instruments are
configured with the default security code 0000 which
allows unrestricted access to all configuration
functions.
To enter a new security code select CodE from the
configuration menu and press ( which will cause
the Set Point Station to display the existing security
code with one digit flashing. The flashing digit can
be adjusted using the & and * push buttons,
when set as required operating the ( button will
transfer control to the next digit.
18

When all the digits have been adjusted press ) to
return to the CodE prompt. The revised security code
will be activated when the Set Point Station is
returned to the operating mode. Please contact
B KA associates sales department if the security
code is lost.
6.13 Reset t fact ry defaults: r5Et
This function quickly returns to the BA427 -SS Set
Point Station to the factory default configurations
shown in section 6.
To reset the Set Point Station select r5Et from the
configuration menu and press (. To prevent
accidental resetting the request must be confirmed
by entering 5urE. Using the * button set the first
flashing digit to 5 and press ( to transfer control to
the second digit, which should be set to u. When
5urE has been entered pressing the ) button will
reset the configuration menus and return the Set
Point Station to the operating mode.
19

7. MAINTENANCE
7.1 Fault finding during c mmissi ning
If a BA427 -SS Set Point Station fails to function
during commissioning the following procedure should
be followed:
Sympt m Cause S luti n
No loop current Incorrect wiring Check wiring
There should be
6.1 to 30V
between terminals
1 & 3 with terminal
1 positive.
With an optional
backlight which is
loop powered,
there should be
10V to 30V
between terminals
3 & 12 with
terminal 12
positive.
No loop current
0V between
terminals 1 & 3 or
between terminals
3 & 12 if optional
backlight is loop
powered.
Incorrect wiring
or no power
supply
Check supply
voltage and
voltage drop
caused by all the
instruments in the
loop.
Unstable 4/20mA
loop current.
Noisy power
supply or
insufficient
voltage to power
all the
instruments in
the loop.
liminate ripple on
power supply or
increase supply
voltage.
Unable to enter
configuration
menu.
Incorrect
security code
entered.
nter correct
security code, or
contact B KA if
the code has been
lost.
BA427 -SS
displays
LP Lo
Voltage between
BA427 -SS
terminal 1 & 3 is
too low,
Increase 4/20mA
loop supply
voltage.
7.2 Fault finding after c mmissi ning
ENSURE PLANT SAFETY BEFORE
STARTING MAINTENANCE
Live maintenance is permitted n
intrinsically safe equipment installed
in a hazard us area, but nly
certified test equipment sh uld be
used unless a gas clearance
certificate is available.
If a BA427 -SS Set Point Station fails after it has
been functioning correctly follow the procedure
shown in section 7.1. If this does not reveal the
cause of the fault, it is recommended that the Set
Point Station is replaced.
7.3 Servicing
We recommend that faulty BA427 -SS Set Point
Stations are returned to B KA associates or to our
local agent for repair.
7.4 R utine maintenence
The mechanical and electrical condition of the
instrument should be regularly checked. Initially
annual inspections are recommended, but the
inspection frequency should be adjusted to suit the
environmental conditions.
7.5 Guarantee
Set Point Stations which fail within the guarantee
period should be returned to B KA associates or our
local agent. It is helpful if a brief description of the
fault symptoms is provided.
7.6 Cust mer c mments
B KA associates is always pleased to receive
comments from customers about our products and
services. All communications are acknowledged and
whenever possible, suggestions are implemented.
20