BEKA BA478C User manual

Issue 8
27th February 2015
BA478C
Intrinsically safe
panel mounting
indicating temperature
transmitter
Issue 8

2
1. Description
2. Documentation
3. Operation
3.1 Controls
4. Intrinsic safety certification
4.1 ATEX certificate
4.2 Zones, gas groups & T rating
4.3 Special conditions for Zone 0 installation
4.4 Certification label information
4.5 Input terminals 1, 2, 3 & 4
4.6 4/20mA output – terminals 5 & 6
5. Electrical system design
5.1 Use with Zener barriers
5.2 Use with galvanic isolators
5.3 Use as a temperature indicator
6. Installation
6.1 Location
6.2 Installation procedure
6.3 EMC
7. Configuration
7.1 Configuration menu
7.1.1 Access
7.1.2 Summary of functions
7.2 Description of configuration menu functions
7.2.1 Transmitter input ‘InPut’
7.2.2 Thermocouple type ‘t.tYPE’
7.2.3 Units of digital display ‘dEG’
7.2.4 Display resolution ‘rESn’
7.2.5 Cold junction compensation ‘CJC’
7.2.6 Sensor fault analogue indication ‘FAuLT’
7.2.7 Configuration of 4/20mA output ‘CAL’
7.2.8 Configuration of bargraph display ‘bAr’
7.2.9 Access code ‘CodE’
7.2.10 Resistance thermometer type ‘r.tYPE’
7.2.11 Decimal point position ‘dP’
7.2.12 Lower input & display ‘in-Lo’
7.2.13 Higher input & display ‘in-Hi’
7.3 Configuration defaults
8. Configuration example
9. Maintenance
9.1 Fault finding during commissioning
9.2 Fault finding after commissioning
9.3 Servicing
9.4 Routine maintenance
9.5 Guarantee
9.6 Customer comments
10. Accessories
10.1 Scale marking
10.2 Tag number
10.3 Alarms
10.3.1 Solid state output
10.3.2 Intrinsic safety
10.3.3 Alarm configuration
10.3.4 Alarm selection ‘Alr1’ & ‘Alr2’
10.3.5 Alarm enable ‘EnbL’
10.3.6 Setpoint adjustment ‘SP1’
10.3.7 Alarm function ‘’Hi.Lo’
10.3.8 Alarm output status ‘no.nC’
10.3.9 Hysteresis ‘HStr’
10.3.10 Alarm delay ‘dELA’
10.3.11 Alarm silence time ‘SiL’
10.3.12 Access setpoint ‘ACSP’
10.3.13 Adjusting alarm setpoints from
operational mode.
Appendix 1
FM Approval for use in the USA and
cFM Approval for use in Canada
Appendix 2
IECEx certification
CONTENTS
The BA478C is CE marked to show compliance with the European Explosive Atmospheres
Directive 94/9/EC and the European EMC Directive 2004/108/EC

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1. DESCRIPTION
The BA478C is a panel mounting, intrinsically safe
4/20mA loop powered temperature transmitter with a
large easy to read display. The instrument, which is
HARTenabled, may be conditioned on-site to
operate with most common thermocouples and
resistance thermometers and will provide a linear
4/20mA output proportional to temperature, plus a
digital temperature display. Voltage and resistance
inputs may be scaled allowing the BA478C to display
variables other than temperature such as position
and weight.
Optional factory fitted alarms provide two galvanically
isolated solid state outputs that may be
independently configured for high or low operation.
For installation in poorly illuminated areas, an
optional factory fitted loop powered display backlight
is available.
The BA478C has been certified intrinsically safe for
use in flammable gas atmospheres by European
Notified Body Intertek Testing and Certification Ltd
(ITS) and complies with the ATEX Directive 94/9/EC.
For international applications, the BA478C has FM,
cFM and IECEx intrinsic safety certification – see
Appendix 1 and 2.
Fig 1 Simplified block diagram
2. DOCUMENTATION
This instruction manual describes the installation and
configuration of the BA478C Indicating Temperature
Transmitter for ATEX intrinsically safe applications.
System design information for IECEx and other non-
ATEX certifications are included in separate
appendices to this manual. The transmitter is HART
Registered and is compliant with HART protocol
standard revision 7. HARTcommissioning
information is included in the BA47X/67X Indicating
Temperature Transmitter HARTInterface Guide
which may be downloaded from
www.beka.co.uk/manuals
3. OPERATION
Fig 1 shows a simplified diagram of the BA478C
Indicating Temperature Transmitter. The input,
which may be from a resistance thermometer,
thermocouple, or a dc voltage or resistance, is
digitised and transferred to the instrument processor
via an optical isolator. The processor linearises the
input signal, displays the resulting temperature in the
selected units and controls the 4/20mA output
current.
3.1 Controls
All functions of the transmitter may be configured via
the six front panel push buttons – see Fig 5.
Buttons respond within 0.5 seconds of being
operated and unless continuously pushed the
transmitter display will return to the operating mode
after 2 seconds.
In the operational mode, i.e. when the transmitter is
displaying the input signal, these push buttons have
the following functions:
Button Function
While this button is operated the transmitter
will show the display corresponding to 4mA
output.
▲While this button is operated the transmitter
will show the display corresponding to
20mA output.
+Transmitter displays output current in mA
followed by output as % of the range.
P + Transmitter displays HARTshort address
followed by firmware version number.
P + EEntry to configuration menu.
When fitted with optional alarms
P + Entry to alarm set point menu. See 10.3.12
E + Transmitter displays alarm 1 setpoint
E + Transmitter displays alarm 2 setpoint
P Activated alarm reverts to the non-alarm
condition for the configured alarm silence
time. See 10.3.11

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4. INTRINSIC SAFETY CERTIFICATION
The BA478C Indicating Temperature Transmitter is
intrinsically safe allowing installation in Zone 1 or 2
when protected by a safe area Zener barrier or
galvanic isolator. It may also be installed in Zone 0
if special conditions are observed – see 4.3.
4.1 ATEX certificate
Notified Body Intertek Testing and Certification Ltd
have issued the BA478C with an EC-Type
Examination Certificate number ITS09ATEX26156X.
This states that the transmitter is intrinsically safe and
complies with requirements for Group II, Category 1G
Ex ia IIC T5 equipment. The transmitter bears the
community mark and subject to local codes of
practice may be installed in any of the European
Economic Area (EEA) member countries. ATEX
certificates are also acceptable for installations in
Switzerland.
This instruction manual describes ATEX installations
conforming with EN 60079-14 Electrical Installations
in Hazardous Areas. When designing systems for
installation outside the UK the local Code of Practice
should be consulted.
4.2 Zones, gas groups and T rating
The BA478C has been certified as Group II Category
1G Ex ia IIC T5 apparatus. When connected to a
suitable certified system the BA478C may be
installed in:
Zone 0 explosive gas air mixture
continuously present.
Note: Special conditions apply
see section 4.3
Zone 1 explosive gas air mixture
likely to occur in normal
operation.
Zone 2 explosive gas air mixture not likely
to occur, and if it does will only
exist for a short time.
Be used with gases in groups:
Group A propane
Group B ethylene
Group C hydrogen
Having a temperature classification of:
T1 450oC
T2 300oC
T3 200oC
T4 135oC
T5 100oC
At an ambient temperature between –40 and +70ºC.
This allows the BA478C to be installed in all Zones
and to be used with most common industrial gases.
4.3 Special conditions for Zone 0 installations
The BA478C ATEX certificate has an ‘X’ suffix which
indicates that the transmitter is subject to special
conditions for safe use, which are:
WARNING
The BA478C Indicating Temperature
Transmitter when installed in a Zone 0
potentially explosive atmosphere shall be
installed such that even in the event of
rare incidents, an ignition source due to
impact or friction between the aluminium
enclosure at the rear of the instrument
mounting panel and iron/steel is
excluded.
These special conditions only apply in the very
unlikely event that the transmitter is installed in a
Zone 0 hazardous area. The special conditions
result from the aluminium enclosure and mean that
when installed in a Zone 0 hazardous area, the rear
of the instrument, which will be behind the instrument
mounting panel, should be protected from impact.
4.4 Certification label information
The certification information label is fitted in a recess
on the top outer surface of the enclosure. It shows
details of the ATEX certification, BEKA associates
name and location plus the year of manufacture.
IECEx certification information is also included. The
label on some versions of the transmitter will also
show non-European certification information.
The instruments serial number is shown on the rear
panel adjacent to the terminals.

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4.5 Input terminals 1, 2, 3 and 4
The transmitter’s input terminals may be connected
to any floating or earthed sensor complying with the
requirements for simple apparatus. i.e. a sensor that
generates less than 1.5V; 100mA or 25mW, such as
a thermocouple, resistance thermometer or a
potentiometer.
The transmitter input may also be connected directly
to a voltage source that does not comply with the
requirements for simple apparatus, providing safety is
assessed using the entity concept.
The safety parameters for terminals 1, 2, 3 & 4 are:
Uo = 6.0V
Io = 30.3mA
Po = 46mW
Ui = 6.0V
Ii = 100mA
Pi = 0.194W
Co = 23.8µF
Lo = 3mH
4.6 4/20mA output - terminals 5 & 6
The BA478C Indicating Temperature Transmitter is
loop powered via these terminals which have the
following input safety parameters:
Ui = 28V
Ii = 200mA
Pi = 0.85W
When installed in a hazardous area the transmitter
must be powered via an ATEX certified Zener barrier
or galvanic isolator with output safety parameters
equal to or less than the above.
The equivalent internal capacitance and inductance
at terminals 5 & 6 is:
Ci = 46.5nF
Li = 0.01mH
5. ELECTRICAL SYSTEM DESIGN
The BA478C is a smart HARTenabled loop
powered 4/20mA Indicating Temperature Transmitter.
Intrinsic safety certification allows the instrument and
sensor to be installed in any gas hazardous area
providing that the transmitter is powered via a
certified Zener barrier or galvanic isolator.
For installation in poorly illuminated areas the
BA478C is available with an optional factory fitted
display backlight. No additional wiring of power
supply is required, but the minimum operating voltage
of the transmitter is increased as shown below.
without backlight 9.0 to 28V
with backlight 15.5 to 28V
When the transmitter is fitted with an optional display
backlight the increased minimum operating voltage
usually precludes the use of Zener barriers.
5.1 Use with Zener barriers
There are three requirements when designing a
BA478C loop using Zener barrier(s):
1. The intrinsic safety output parameters of the
Zener barrier must be equal to or less than:
Uo = 28V
Io = 200mA
Po = 0.85W
2. The voltage between terminal 5 & 6 of the
BA478C must be between 9 & 28V.
Note: Zener barriers are not normally able to
power a BA478C transmitter fitted with an
optional display backlight which requires a
minimum operating voltage of 15.5V between
terminals 5 & 6.
3. The maximum supply voltage must not
exceed the maximum working voltage of the
Zener barrier(s).
Fig 2 illustrates the simplest and least expensive
configuration in which a BA478C is powered from an
isolated (floating) power supply. Only one barrier is
required, as the other wire is earthed at the barrier
busbar.

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Fig 2 BA478C powered from floating supply
If a common power supply is used to operate multiple
loops, the negative side of the supply is normally
earthed. To also allow the negative side of the
4/20mA load to be earthed it is necessary to have a
Zener barrier in each of the two wires entering the
hazardous area as shown in Fig 3.
Fig 3 BA478C powered from a common supply
When designing a transmitter loop it is necessary to
establish that the sum of the voltage drops caused by
the transmitter, Zener barriers, the load and the cable
resistance is less than the minimum supply voltage.
For the transmitter loop shown in Fig.3
Minimum operating voltage of BA478C 9.0V
without optional backlight.
Maximum voltage drop caused by 28V 6.8V
93mA Zener barrier.
(340x 20mA)
Maximum voltage drop caused by 1.6V
diode return Zener barrier.
Maximum voltage drop caused by 5.0V
250load.
(250x 20mA)
Maximum voltage drop caused by 0.2V
cable resistance.
(10x 20mA)
______
Total maximum voltage drop 22.6V
The power supply voltage must therefore be above
22.6V but below the maximum working voltage of the
28V 93mA barrier which is likely to be about 26.5V.
5.2 Use with Galvanic Isolators
A galvanic isolator can supply a higher voltage than a
Zener barrier to a loop powered transmitter and is
able to power a BA478C transmitter fitted with an
optional display backlight which has a minimum
operating voltage of 15.5V. Although an isolator is
more expensive than a Zener barrier it does not
require a high integrity earth. For small systems
where a high integrity earth is not already available a
galvanic isolator may reduce the overall installation
cost. Fig 4 shows a typical temperature transmitter
loop.
Fig 4 BA478C powered via galvanic isolator

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Any ATEX certified 4/20mA repeater power supply or
transmitter power supply galvanic isolator may be
used. There are three requirements when designing
a BA478C loop incorporating a galvanic isolator:
1. The intrinsic safety output parameters of the
galvanic isolator must be equal to or less
than:
Uo = 28V
Io = 200mA
Po = 0.85W
2. The isolator must supply a minimum output
voltage at 20mA of:
BA478C without backlight 9.0V
BA478C with backlight 15.5V
3. If HARTcommunication is to be used the
galvanic isolator must be suitable for powering
‘smart’ transmitters, i.e. it must be transparent
to HARTsignals.
5.3 Use as a temperature indicator
The BA478C may also be used as just a temperature
indicator by ignoring the instrument’s 4/20mA output
current. The same Zener barriers or galvanic
isolators required for transmitter operation are
required, but the load resistor may be omitted.
6. INSTALLATION
6.1 Location
The BA478C is housed in a robust aluminium
enclosure with a toughened glass window mounted in
a Noryl bezel. The front of the instrument provides
IP66 protection and a gasket seals the joint between
the instrument enclosure and the panel. The
instrument may be installed in any panel providing
the environmental limits shown in the specification
are not exceeded.
Fig 5 shows the overall dimensions of the BA478C
and the panel cut-out. To achieve an IP66 seal
between the instrument enclosure and the panel, the
smaller cut-out must be used and the instrument
secured with four panel mounting clips.
The BA478C liquid crystal display has maximum
contrast when viewed from directly ahead and slightly
below the centre line of the instrument.
Fig 5 BA478C dimensions

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6.2 Installation Procedure
a. Insert the BA478C into the instrument panel
cut-out from the front of the panel with the
sealing gasket positioned as shown in Fig 6.
b. Fix panel mounting clips to opposite sides of
the instrument and tighten. Recommended
tightening torque is 22cNm (1.95lbf in). Do not
over tighten. Four clips are required to
achieve an IP66 seal between the instrument
enclosure and the panel.
c. Connect the panel wiring to the rear terminal
block as shown in Fig 6. To simplify
installation, the terminals are removable so
that panel wiring can be completed before the
instrument is installed.
Fig 6 Installation and terminal connections
6.3 EMC
The BA478C complies with the requirements of the
European EMC Directive 2004/108/EC. For specified
immunity, all wiring should be in screened twisted
pairs with the screens earthed at one point in the safe
area.

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7. CONFIGURATION
The BA478C Indicating Temperature Transmitter
may be configured and calibrated via HARTdigital
communication, or configuration may be performed
using the menu accessed via the front panel push
buttons see Fig 5.
Configuration and calibration via HARTmay be
performed using a portable configurator connected
directly to the BA478C or to the galvanic isolator
powering the transmitter, alternatively proprietary
configuration software operating on a personal
computer may be used. In addition to the
configuration functions available via the transmitter
push buttons, HARTcommunication enables loop
calibration and custom linearisation to be performed.
Details of the HARTcommunication are contained in
the BEKA HARTInterface Guide which may be
downloaded from www.beka.co.uk/manuals
7.1 Configuration menu
Throughout this manual the BA478C push buttons
are identified P E ▼▲and legends displayed by
the transmitter are shown within inverted commas
e.g. ‘CAL’ and ‘dEG’. Section 7.1.2 contains a
summary of each configuration function including a
cross reference to a more detailed description.
The functions contained in the configuration menu
vary depending upon the transmitter input selected,
see Figs 7, 8 & 9.
When the transmitter is being configured, the
transmitter 4/20mA output current is locked at the
value prior to entering the configuration menu.
When the optional alarms are fitted additional
functions are added to the configuration menu which
are described in section 10.3.
7.1.1 Access
Access to the configuration menu is obtained by
operating the Pand Ebuttons simultaneously. If the
transmitter is not protected by an access code the
first parameter 'InPut’ will be displayed. If the
transmitter is protected by an access code, ‘CodE’
will be displayed first. Pressing Pwill allow the four
digit security code to be entered digit by digit using
the or button to adjust the flashing digit and Pto
move control to the next digit. When the correct code
has been entered, pressing Ewill cause the first
parameter ‘InPut’ to be displayed. If an incorrect
code is entered, or no button is pressed for ten
seconds, the transmitter will automatically return to
the operating mode.
If the transmitter displays ‘LoC’ when the Pand E
buttons are operated simultaneously, the transmitter
push buttons have been locked by a HART
command - see the BEKA HARTInterface Guide
which may be downloaded from
www.beka.co.uk/manuals
7.1.2 Summary of functions
The functions that may be configured vary depending
upon the input selected.
Thermocouple and RTD inputs
The BA478C will always display sensor temperature.
Configuration allows:
Digital display units and resolution to be selected.
Bargraph display to represent required part of the
digital displayed range.
4/20mA output current to represent required part
of transmitter input range.
Voltage and resistance inputs
The BA478C can display the voltage or resistance
input in any engineering units.
Configuration allows:
Zero and span of digital display to be adjusted.
Bargraph display to represent required part of the
digital displayed range.
4/20mA output current to represent required part
of the transmitter input range.
Each of the functions in the configuration menu is
summarised below, including a cross-reference to a
more detailed description.
Transmitter Summary
display of function
‘InPut’ Transmitter input
Selects one of the following inputs:
Thermocouple ‘tHC’
3 wire RTD ‘3rtd’
4 wire RTD ‘4rtd’
Differential RTD ‘d_rtd’
Voltage ‘Volt’
3 wire resistance ‘3rES’
4 wire resistance ’4rES’
See section 7.2.1
The content of the configuration menu depends upon
which transmitter input is selected, see following
summary and Figs 7, 8 and 9.

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For Thermocouple Input – see Fig 7
Transmitter Summary
display of function
‘t.tYPE’ Thermocouple type
Selects 1 of 8 common types of
thermocouple.
See section 7.2.2
‘dEG’ Units of digital display
Selects 1 of 4 units of temperature.
See section 7.2.3
‘rESn’ Display resolution
Selects low or high display resolution.
See section 7.2.4
‘CJC’ Cold junction compensation
Turns thermocouple cold junction
compensation on or off.
See section 7.2.5
‘FAuLt’ Sensor fault analogue indication
Selects 1 of 3 under/over range output
currents to indicate that a sensor fault has
been detected. Analogue fault indication
may be disabled.
See section 7.2.6
‘CAL’ Configuration of 4/20mA output
Defines transmitter input at which
transmitter output is 4 & 20mA.
See section 7.2.7
‘bAr’ Configuration of bargraph display
Defines digital display at which bargraph
is zero and full scale.
See section 7.2.8
‘CodE’ Access code for configuration menu
Enters four digit configuration menu
access code. Default code 0000 disables
this function.
See section 7.2.9
For Resistance Thermometer (RTD) Input see Fig 8
Transmitter Summary
display of function
‘r.tYPE’ Resistance thermometer type
Selects Pt100 or Pt1000 sensor
See section 7.2.10
‘dEG’ Units of digital display
Selects 1 of 4 units of temperature.
See section 7.2.3
‘rESn’ Display resolution
Selects low or high display resolution.
See section 7.2.4
Transmitter Summary
display of function
‘FAuLt’ Sensor fault analogue indication
Selects 1 of 3 under/over range output
currents to indicate that a sensor fault has
been detected. Analogue sensor fault
indication may be disabled.
See section 7.2.6
‘CAL’ Configuration of 4/20mA output
Defines transmitter input at which
transmitter output is 4 & 20mA.
See section 7.2.7
‘bAr’ Configuration of bargraph display
Defines digital display at which bargraph
is zero and full scale.
See section 7.2.8
‘CodE’ Access code for configuration menu
Enters four digit configuration menu
access code. Default code 0000 disables
this function.
See section 7.2.9
For Voltage and Resistance Inputs – see Fig 9
Transmitter Summary
display of function
‘dP’ Decimal point position
Defines position of displayed decimal
point.
See section 7.2.11
‘in-Lo’ Lower input and display
Defines lower voltage or resistance input
‘inVAL’ and corresponding digital display
‘diSP’.
See section 7.2.12
‘in-Hi’ Higher input and display
Defines higher voltage or resistance input
‘inVAL’ and corresponding digital display
‘diSP’.
See section 7.2.13
‘CAL’ Configuration of 4/20mA output
Defines the transmitter input at which
transmitter output is 4 & 20mA.
See section 7.2.7
‘bAr’ Configuration of bargraph display
Defines digital display at which bargraph
is zero and full scale.
See section 7.2.8
‘CodE’ Access code for configuration menu
Enters four digit configuration menu
access code. Default code 0000 disables
this function. See section 7.2.9