BEKA BA358C User manual

Issue: 4
1st October 2010
BA358C
Intrinsically safe
4/20mA loop powered
panel mounting
rate totaliser
Issue 4
Certification
information
label
Rate
displa
y
A
nnunciators for
optional alarms
Rotatin
g
flow
indicato
r
Total
display

2
1. Description
2. Operation
2.1 Controls
2.2 Displays
3. Intrinsic Safety Certification
3.1 ATEX certificate
3.2 4/20mA input
3.3 Reset terminals
3.4 Reset terminals
3.5 Certification label information
4. System Design for Hazardous Areas
ATEX certification
4.1 Flow transmitter loops
4.2 Remote indication
4.3 Resetting the total display
5. Installation
5.1 Location
5.2 Installation procedure
5.3 EMC
6. Programming and Calibration
6.1 Calibration structure
6.2 Accessing programme functions
6.3 Summary of programmable
functions
6.4 Root extractor
6.5 Resolution
6.6 Position of decimal place
6.7 Calibration of the rate display
using an external current source
6.8 Calibration of the rate display
using internal reference
6.9 Conditioning sub-menu
6.9.1 AC rejection
6.9.2 Calibration of internal
references
6.10 Resetting grand total
6.11 Timebase
6.12 Function of the Ppush-button
6.13 Total scale factor
6.14 Percentage clip-off
6.15 Local reset of total display
6.16 Security code
6.17 Over and under-range
7. Calibration Examples
7.1 Using an external current source
7.2 Using the internal references
8. Maintenance
8.1 Fault finding during commissioning
8.2 Fault finding after commissioning
8.3 Servicing
8.4 Routine maintenance
8.5 Guarantee
8.6 Customer comments
9. Accessories
9.1 Scale card
9.2 Tag number
9.3 Alarms
9.3.1 Solid state output
9.3.2 Intrinsic safety
9.3.3 Programming and
adjustment
9.3.4 Alarm enable
9.3.5 Type of alarm
9.3.6 Setpoint adjustment
9.3.7 Alarm function
9.3.8 Alarm output status
9.3.9 Hysteresis
9.3.10 Alarm delay
9.3.11 Alarm silence time
9.2.12 Access setpoint
9.2.13 Adjusting alarm setpoints
from display mode.
9.4 Display backlight
9.5 Additional front panel protection
10. Index
CONTENTS
The BA358C is CE marked to show compliance with the European Explosive Atmospheres
Directive 94/9/EC and the European EMC Directive 2004/108/EC

3
1. DESCRIPTION
The BA358C is an intrinsically safe 4/20mA
loop-powered rate totaliser primarily
intended for use with flowmeters. The
instrument simultaneously displays the rate
of flow and the total flow in engineering units
on two separate displays. The BA358C only
introduces a 1.1V drop which allows it to be
installed into almost any 4/20mA flow loop.
No additional power supply or battery is
required.
The BA358C has been certified intrinsically
safe by European Notified Body Intertek
Testing Sevices (ITS) to the ATEX Directive
94/9/EC. The EC-Type Examination
Certificate specifies that under fault
conditions the voltage, current and power at
input terminals 1 and 3 will not exceed those
specified for simple apparatus in Clause 5.4
of EN50020:1994.
Safety approvals from authorities outside
Europe are being obtained, please contact
BEKA associates for the latest information.
Housed in a robust 72 x 144 panel mounting
DIN enclosure, the BA358C has an IP65
front panel which will not support a static
charge, and is supplied with a gasket to seal
the joint between the instrument and the
panel.
2. OPERATION
Fig 1 shows a simplified block diagram of a
BA358C. The 4/20mA input current flows
through resistor R1 and forward biased
diode D1. The voltage developed across
D1, which is relatively constant, is multiplied
by a switch mode power supply and used to
power the instrument. The voltage
developed across R1, which is proportional
to the 4/20mA input current, provides the
input signal for the analogue to digital
converter.
Each time a 4/20mA current is applied to the
instrument, initialisation is performed. After
a short delay the following display sequence
occurs:
All segments of the display are activated
for about 3 seconds.
Decimal points on large display are
sequentially activated for about 3
seconds.
Rate display and totaliser start to function
using calibration information stored in the
instrument's permanent memory.
If the 4/20mA current is disconnected during
operation the latest total and grand total are
stored in permanent memory.
Fig 1 Simplified block diagram of BA358C
2.1 Controls
The BA358C is controlled and calibrated via
four front panel push-button switches. In the
display mode i.e. when the instrument is
displaying rate of flow and total flow, these
switches have the following functions:
Summary of Switch Functions
PDisplays input current in mA or
as a percentage of span.
Down Shows rate display calibration at
4mA input
Up Shows rate display calibration at
20mA input
E+Down Grand total –
displays least significant 8 digits
E+Up Grand total –
displays most significant 8
digits.
Down Resets total display
+Up programmable function

4
Full Description of Switch Functions
PWhile this button is pushed the rate
display will show the input current
in mA, or as a percentage of the
instrument span depending upon
how the instrument has been
programmed. When the button is
released the normal display in
engineering units will return. The
function of this push-button may be
modified when alarms are fitted to
the instrument.
Down While this button is pushed the
instrument will show the calibrated
rate display with 4mA input -
usually zero for flow applications.
When the button is released the
flow rate will again be displayed.
Up While this button is pushed the
instrument will show the calibrated
rate display with 20mA input.
When the button is released the
flow rate will again be displayed.
E+ While these two buttons are
Down pushed the total display will show
the least significant eight digits of
the grand total, and the grand total
annunciator will be activated.
E+ While these two buttons are
Up pushed the total display will show
the most significant eight digits of
the grand total and the grand total
annunciator will be activated.
Down+ Resets the total display to zero
Up when these two push-buttons are
operated simultaneously.
Selectable function from
programme menu.
See section 6.15
2.2 Displays
The BA358C has two digital displays and
associated annunciators, plus a flow
indicator as shown on page 1.
Rate Shows the flow rate on the smaller
display five digit display.
Total Shows total flow since the
display instrument was last reset on the
larger eight digit display.
Flow Disc in the lower left hand corner
indicatorof the display 'rotates' when the
input current exceeds 4mA.
3. INTRINSIC SAFETY CERTIFICATION
3.1 ATEX certificate
The BA358C has been issued with an EC-
Type Examination Certificate by Notified
Body Intertek Testing Services (ITS,
formerly ERA Technology Ltd) confirming
compliance with the European ATEX
Directive 94/9/EC for Group II, Category 1,
gas atmospheres, EEx ia IIC T5. The
instrument bears the Community Mark and,
subject to local codes of practice, may be
installed in any of the EU member countries.
i.e. Austria, Belgium, Denmark, Finland,
France, Germany, Greece, Ireland, Italy,
Luxembourg, The Netherlands, Portugal,
Spain, Sweden and the United Kingdom.
ATEX certificates are also accepted in
Norway, Iceland, Liechtenstein and
Switzerland.
This manual describes installations which
conform with EN60079:Part 14 Electrical
Installation in Hazardous Areas. When
designing systems for installation outside the
UK, the local Code of Practice should be
consulted.
3.2 4/20mA input
In Europe, sources of energy which do not
generate more than 1.5V; 100mA and
25mW are, for intrinsic safety purposes,
considered to be simple apparatus.
Although the BA358C indicator does not
itself comply with the requirements for
simple apparatus, the EC-Type Examination
Certificate specifies that under fault
conditions the voltage, current and power at
the 4/20mA input terminals 1 and 3 will not
exceed those specified for simple apparatus.
This allows the BA358C 4/20mA input
terminals to be connected into any
intrinsically safe circuit protected by a Zener
barrier or galvanic isolator, providing the
output parameters of the circuit do not
exceed:
Uo 30V dc
Io 200mA
Po 0.85W
The BA358C EC-Type Examination
Certificate specifies that the maximum
equivalent capacitance and inductance
between the two 4/20mA input terminals 1
and 3 is: Ci = 20nF
Li = 10µH
To determine the maximum permissible
cable parameters these figures must be

5
subtracted from the maximum cable
capacitance and inductance permitted by the
system certificate of the loop into which the
BA358C is connected.
3.3 Reset terminals
The BA358C total display may be reset to
zero by connecting the reset terminals RS1
and RS2 together. These two terminals
have the following safety parameters:
Uo 5V dc
Io 1.3mA dc
Po 1.6mW
Ui 28V dc
Ii 98mA
Pi 0.65W
The maximum equivalent capacitance and
inductance between them is:
Ci = 1.2nF
Li = 0µH
The total display may be reset from within
the hazardous area by any mechanically
operated switch having 500V rms insulation.
This may be connected directly to terminals
RS1 and RS2, no Zener barrier or isolator is
required. Alternatively, the BA358C may
be programmed so that the total display is
reset to zero when the Up and Down push-
buttons are operated simultaneously.
To reset the total display from the safe area
a Zener barrier or intrinsically safe relay is
required to transfer the contact closure into
the hazardous area. Acceptable interface
devices and the maximum permissible cable
parameters are defined by the BA358C
system certificates. Almost any intrinsically
safe relay with certification permitting the
contacts to be connected into the hazardous
area may be used. Alternatively, one of the
positive diode return Zener barriers listed in
the system certificate may be used - see Fig
3A.
3.4 Zones, gas groups and T rating
The BA358C has been certified to show
compliance with the requirements for Group
II Category 1G equipment, EEx ia IIC T5.
When connected to a suitable system the
instrument may be installed in:
Zone 0 explosive gas air mixture
continuously present.
Zone 1 explosive gas air mixture
likely to occur in normal
operation.
Zone 2 explosive gas air mixture not
likely to occur, and if it does
will only exist for a short
time.
Be used with gases in groups:
Group A propane
Group B ethylene
Group C hydrogen
Having a temperature classification of:
T1 450oC
T2 300oC
T3 200oC
T4 350oC
T5 100oC
At an ambient temperature between –40 and
+60oC.
Note: the guaranteed operating temperature
is –20 to +60oC
This allows the BA358C to be installed in all
Zones and to be used with most common
industrial gases.
WARNING installation in Zone 0
When installed in a Zone 0 potentially
explosive atmosphere requiring
apparatus of Category 1G, the rate
totaliser shall be installed such that
even in the event of rare incidents, an
ignition source due to impact or
friction between the aluminium
enclosure at the rear of the instrument
mounting panel and iron/steel is
excluded.
3.5 Certification Label Information
The certification label is fitted in a recess on
the side of the enclosure. It shows the
ATEX certification information, the date of
manufacture, serial number plus BEKA
associates’ name and address. Non
European certification information may also
be included. The instrument serial number
is also shown on a separate label adjacent
to the field terminals.

6
4. SYSTEM DESIGN FOR HAZARDOUS
AREAS ATEX Certification
4.1 Flow transmitter loops
A BA358C rate totaliser may be connected
in series with almost any intrinsically safe
4/20mA flow loop and calibrated to display
the rate of flow and total flow. There are
two basic design requirements:
1. The intrinsic safety output parameters
of the 4/20mA loop, which are defined
by the Zener barrier or galvanic isolator,
must be less than:
Uo 30V dc
Io 200mA
Po 0.85W
2. The loop must be able to tolerate the
additional 1.1V required to operate the
indicator, increases to 1.2V at -20ºC.
Fig 2 illustrates an application in which a
BA358C indicator is connected in series with
a 2-wire flow transmitter protected by a two
channel Zener barrier.
Fig 2 BA358C in a flow loop
4.2 Remote indication
A BA358C may be driven via an intrinsically
safe interface from a 4/20mA safe area
signal to provide a remote indication of rate
and total flow within a hazardous area. The
type of interface is not critical, either a Zener
barrier or a galvanic isolator may be used,
providing that Uo, Io and Po are not
exceeded.
If one side of the 4/20mA current loop may
be earthed, a single channel Zener barrier
provides the lowest cost protection. If the
4/20mA signal is not isolated, then two
Zener barriers, a two channel Zener barrier
or a galvanic isolator must be used.
When the hazard is a IIC gas, and two single
channel Zener barriers or a two channel
Zener barrier are used, only one barrier or
channel may be a 28V 300ohm device. A
10V 50ohm or diode return barrier may be
used for the second channel to form a safe
combination.
Again it is necessary to ensure that the
voltage capability of the 4/20mA signal is
sufficient to drive the rate totaliser plus the
voltage drop introduced by the intrinsically
safe interface.
Figs 3A, 3B and 3C show the alternative
circuits which may be used.
Fig 3A Simplest circuit with one side of
4/20mA current loop connected to
earth. Also shows optional resetting
from safe area.

7
Fig 3B Two Zener barrier channels are
required if the 4/20mA current loop
can't be earthed at the barrier
busbar. Also shows optional
resetting from hazardous area
Fig 3C Galvanic isolator may be used with
any 4/20mA current loop.
4.3 Resetting the total display
The total display may be reset to zero by an
external switch located in the safe or the
hazardous area. Fig 3A illustrates resetting
from the safe area via a single channel
diode return Zener barrier. A certified
intrinsically safe relay or certified opto-
isolator may also be used.
Fig 3B shows how the total display may be
reset by an external switch in the hazardous
area. The switch must be mechanically
operated and able to withstand a 500V dc
insulation test so that it complies with the
requirements for simple apparatus. No
Zener barrier or galvanic isolator is required.
The BA358C may also be programmed to
reset the total display to zero when the Up
and Down buttons are operated
simultaneously -see 6.15

8
5. INSTALLATION
5.1 Location
The BA358C is housed in a robust
aluminium enclosure with a polyester
membrane front panel surrounded by a
Noryl bezel. The front of the instrument
provides IP65 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 4 shows the overall dimensions of the
BA358C and the panel cut-out. To achieve
an IP65 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 BA358C liquid crystal display has
maximum contrast when viewed from
directly ahead and slightly below the centre
line of the instrument. For reflective displays
there is little degradation of contrast when
viewed from above the centre line, but slight
degradation may be noticeable when the
instrument is fitted with a backlight.
Fig 4 BA358C dimensions
5.2 Installation Procedure
a. Insert the BA358C into the instrument
panel cut-out from the front of the
panel.
b. Fix panel mounting clips to opposite
sides of the instrument and tighten
until the instrument is secure as
shown in Fig 5. Four clips are
required to achieve an IP65 seal
between the instrument enclosure and
the panel.
c. Connect the panel wiring to the rear
terminal block(s) as shown in Fig 5
To simplify installation, the terminals
are removable so that panel wiring
can be completed before the
instrument is installed.
Fig 5 Installation and terminal connections
5.3 EMC
The BA358C complies with the requirements
of the European EMC Directive 89/336/EEC.
For specified immunity all wiring should be in
screened twisted pairs, with the screens
earthed in the safe area.

9
6. PROGRAMMING & CALIBRATION
The BA358C is programmed and calibrated
via four front panel push-buttons. All the
programming functions are contained in an
easy to use menu which is shown
diagrammatically in Figs 7A and 7B. Each
function is summarised in section 6.3 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, it is recommended that at least the
summary of the programmable functions in
section 6.3 is read before attempting
programming or recalibration.
When the instrument is fitted with alarms,
the basic menu is expanded to include the
alarm functions that are described in section
9.3 of this manual.
Note: While the instrument is being
programmed or calibrated totalisation is
suspended, any flow occurring during this
time will not be recorded.
6.1 Calibration structure
Fig 6 shows the BA358C calibration
structure. The 4/20mA input current, which
in flow applications represents flow rate, is
displayed on the five digit rate display.
Using the instrument 'CAL' or 'SEt' functions
this display may be calibrated to show the
flow rate in engineering units. Both the
zero (display at 4mA) and the span (display
at 20mA) are adjustable, although for flow
application the display at 4mA is usually
zero. The position of the decimal point in
the rate display is defined by the d.p.
function. To simplify calibration the BA358C
uses floating point arithmetic, moving the
rate display decimal point position will
therefore affect totalisation.
The BA358C total display is calculated from
the rate display using two serial factors: the
timebase 't-bASE' and the total scaling factor
'SCALE-t'. To calculate total flow the
timebase divides the rate display according
to whether the rate display represents flow
per second, per minute or per hour. The
total scaling factor 'SCALE-t' is a wide range
programmable dividing factor allowing the
total display to be in different units from the
rate display.
For example, if a BA358C is displaying rate
in litres per minute, setting 'SCALE-t' to
4.5461 produces a total display in UK
gallons. Alternatively, setting 'SCALE-t' to
4546.1 will produce a total display in
thousands of UK gallons.
The total is calculated and the display
updated once per second. When total
alarms are used for batching applications,
this resolution may define the accuracy of
the system.
Fig 6 Calibration structure
6.2 Accessing programming functions
Throughout this manual push-buttons are
shown in italics e.g. Por Up push-button,
and legends displayed by the instrument 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

10
instrument will display 'COdE'. Press Pto
clear this prompt and enter the security code
for the instrument using the Up or Down
push-button to adjust each digit, and the P
push-button to move control to the next digit.
If the correct code has been entered
pressing Ewill cause the first parameter
'root' to be displayed. If an incorrect code is
entered, or a push-button is not operated,
the instrument will timeout after ten seconds
and automatically return to the display
mode.
Apart from defining the position of the
decimal point in the rate display all
programme functions and prompts are
shown on the large eight digit display.
Once within the main programme menu the
required parameter can be reached by
scrolling through the menu using the Up and
Down push-buttons as shown by the
programme structure in Figs 7A and 7B.
When returning to the operating mode
following recalibration or changes to any
parameters, the total display will show
circulating decimal points for a few seconds
while the new information is stored in
permanent memory.
All new BA358C rate totalisers are supplied
calibrated as requested at the time of
ordering. If calibration information is not
supplied, the BA358C will be set to display a
rate of 0.00 with 4mA input and 100.00 with
20mA input. The total scale factor will be set
to 1.0000 with a timebase of flow per
second. The instrument can easily be
recalibrated on-site.
6.3 Summary of programmable functions
This section summarises all of the BA358C
programmable functions. When read with
Figs 7A and 7B it provides a quick aid for
calibrating the instrument. If more detail is
required, each section contains a reference
to a full description of the function.
SUMMARY
Display Description of function
'root' Square root extractor
Enables the square root
extractor for linearising the
output from differential
flowmeters.
Percentage CLIP-OFF, below
which the instrument does not
totalise, is automatically set to
5% of rate when the 'root'
function is turned 'On'.
See section 6.4
'rESn' Display resolution
Selects the resolution of the
least significant digit of the rate
display. May be set to 1, 2, 5 or
10 digits.
See section 6.5
'd.P.' Decimal points
Defines the position of the
decimal point in both the rate
and total displays.
See section 6.6
'CAL' Calibration of rate display
using external current source.
Enables the zero and span of
the rate display to be adjusted
using an external current source
such as a calibrator. Also
enables a complete loop to be
calibrated from primary element
to the indicator display.
When used with an accurate
traceable current source this is
the preferred method of
calibration.
See section 6.7

11
Display Description of function
'SEt' Calibration of rate display
using internal references.
Enables the zero and span of the
rate display to be adjusted
without the need for an accurate
input current or disconnection
from the 4/20mA loop.
See section 6.8
'Cond' Indicator conditioning
This is a protected sub-menu
which contains the calibration
routine for the two internal
references 'rEF', and the mains
(line) frequency selection
function 'FrE'.
See section 6.9
CAUTION
Please read sections 6.9 and
6.9.1 of this manual before
changing any of the
parameters in this sub-
menu. Incorrect adjustment
may result in reading errors.
'CLr. Gtot' Clears grand total
This function resets the grand
total to zero when 'CLr YES' is
selected, and 'SurE' is entered to
confirm the instruction.
Note: Once cleared, a grand
total can not be recovered.
See section 6.10
't-bASE' Timebase
Three selectable divisors which
define whether the rate display
represents flow per second, per
minute or per hour.
See section 6.11 & Fig 6.
'C - - P' Function of Ppush-button in
display mode
The instrument may be
programmed to show on the rate
display the input current in
milliamps, or the input as a
percentage when the Ppush-
button is operated in the display
mode. Select ‘PC’ for % of span
and ‘4-20’ to display current.
See section 6.12
Display Description of function
'SCALE-t' Total Scale Factor
Defines the arithmetic
relationship between the rate
and total displays. May be
adjusted between 0.0001 and
65535
SCALE-t = Units of total display
Units of rate display
The same units of
measurements should be used
for the rate and total displays
when calculating SCALE-t
See section 6.13 and Fig 6.
'CLIP-OFF' Percentage Clip off
To prevent the totalisation of
very low flow rates, this function
enables the user to select a
percentage rate below which the
rate display is forced to zero.
Adjustable between 0 and 10%
of flow for linear inputs, and 5 to
10% when the root function is
used to linearise a square law
input.
See section 6.14
'LOC.rSEt' Local reset of total display
When turned 'On' this function
enables the total display to be
reset to zero by simultaneously
operating the Up and Down
push-buttons.
See section 6.15
'COdE' Security code
Defines a four digit numeric code
which must be entered to gain
access to programmable
functions. Default code 0000
disables the security function
and allows unrestricted access to
all programmable functions.
See section 6.16

12
CLr.YES
t-bASE C--P
4-20 00000 00 OFF
LOC-rSET
0000
COdE
When fitted alarms
appear here
Clear
grand total
or
to select CLr-YES
confirmed by
entering
WARNING
Cleared grand
total can not
be recovered
Timebase
or
between
4-20mA and
to toggle
or
Function of
P button
% of span to next digit.
Total scale
to adjust value
Press or
and to move
factor
Press +
to position
decimal point
% clip-off
to adjust value
Press or
between
0 and 10% or
and
pressing
Define Security
Enter by
Code
to move to
next digit
Local reset
or
Fig 7B. Programme Structure
CLr.Gtot
EEEEEEE
EPPEPE
PE PE PEPE
PP
To Cond
function on
Fig 7A
SurE
P E
SurE using
or
to adjust
display and
to move
to next digit
P
CLIP-OFF
SCALE-t
tb-1
to define rate
display timebase
select
tb-1 for flow/sec
tb-60 for flow/min
tb-3600 for flow/hour
to turn the local
reset function
On or OFF.
When On total
display is reset to
zero when
and
are operated
simultaneously

13
1, 2, 5 or 10 digit
rate display
resolution
Display DISPLAY
mode
P
P
P
P
E
P
E
P
E
E
EP
PP
E
E EEP
E
P
E
P
E
P
E
P
EPEPEP EEEP
P
EEEEEEE
E
P
E
function on
Fig 7B
To GLr.tot
Fig 7A. Programme Structure
THESE REFERENCES
BEFORE ATTEMPTING TO ADJUST
READ INSTRUCTION MANUAL
WARNING
Calibration of internal references
internal references
Without need for accurate input
current set required display at
Calibration of rate display using
to move to next digit
4mA by pressing or and
Similarly set the required
full scale display
accurate 20mA input current
scale display using an
Similarly set the required full
to move to next digit
pressing or and
set required zero display by
With accurate 4mA input current
external current source
Calibration of rate display using
displays
toggle between
and to
decimal point
position of
to select
or
Decimal point
or
to select
Resolution
On and OFF
between
to toggle
or
extraction
Square root
Ent
.020A
Ent
.004A50
Cond
SurE
FrE rEF
SPAn
19999
SEt
ZErO
19999
SPAn
1999919999
ZErO
CAL
00000
d.P.
00000000
rESn
10
access
allows direct
Code 0000
next digit
to move to
and
pressing
Enter code by
Security Code
On
root
XXXX
COdE

14
6.4 Root extractor: root
This function is primarily intended for use
with differential flowmeters that have a
square law 4/20mA output. The root
extractor linearises the flow signal and
enables the BA358C to display flow and total
in linear units.
To activate the square root extractor select
'root' from the menu and press Pwhich will
reveal if the function is 'On' or 'OFF'. If the
function is set as required, press E to return
to the menu, or press the Up or Down button
to change the setting, followed by the E
button to return to the main menu.
For reference, the following table shows the
output current from a non-linearised
differential flowmeter.
% of full flow Current output mA
2.5 4.01
10.0 4.16
25.0 5.00
50.0 8.00
75.0 13.00
100.0 20.00
6.5 Resolution: rESn
This function defines the resolution of the
least significant rate 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 Ebutton to return to
the menu.
6.6 Position of the decimal points: d.P.
This function positions the decimal point in
both the rate and total displays.
The rate display can have up to five digits
and the decimal point may be positioned
between any of them, or omitted. The
BA358C uses floating point arithmetic so
moving the position of the rate display
decimal point will affect totalisation.
Similarly the total display has eight digits
and the decimal point may be positioned
between any of them, or may be omitted.
To adjust the position of either decimal
points select 'd.P.' from the main menu and
press Pwhich will activate both displays with
one digit and the following decimal pointof
the total display flashing. If only the least
significant digit is flashing, this indicates that
the decimal point is omitted.
The position of the decimal points can be
moved by pressing the Up or Down push-
buttons. Operating the Ppush-button will
toggle control between the two displays.
When both decimal points have been
correctly positioned press Eto return to the
main menu.
If the application requires flow rate to be the
primary display i.e. shown on the large
display, the d.P. function enables the rate
and total displays to be interchanged. The
rate display will continue to have five digits
but the total display will be reduced from
eight to six digits. The rate and total
annunciators will also be interchanged.
Pressing the Up and Down buttons
simultaneously will interchange the displays.
6.7 Calibration of the rate display using
an external current source: CAL
This function enables the zero and span of
the rate display to be adjusted using an
external current source such as a 4/20mA
calibrator. When used with an accurate
traceable current source this is the preferred
method of calibration.
To calibrate the instrument 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 Pwhich will reveal the current
instrument zero display. For flow
applications this will usually be zero. Each
digit of the rate 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 rate display at 20mA, press the
Up button which will cause the instrument 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 rate 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. The most significant digit, which can be
1 or 2, is set by rolling over the previous
digit. When all the digits have been adjusted
press Eto enter the new span. The
instrument will display 'Ent' for a few
seconds while the information is being

15
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 including the flow
meter.
6.8 Calibration of the rate display using
internal references: SEt
This function enables the zero and span of
the rate display to be adjusted without the
need for an accurate external current
source, or for disconnection from the
4/20mA loop. The accuracy of this method
depends upon the accuracy of the internal
references which should be regularly
calibrated as described in section 6.9.2
To calibrate the rate display select 'SEt' from
the main menu and press P. The instrument
will display 'ZErO', pressing Pagain will
reveal the current display at 4mA. For flow
applications this will usually be zero. Each
digit of the rate 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 E
to return to the 'ZErO' prompt which
completes the adjustment.
To adjust the rate display at 20mA, press the
Up button which will cause the instrument to
display 'SPAn'. Pressing P again will reveal
the existing full scale rate 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. The most significant digit can only be
adjusted by rolling-over the previous digit.
When all the digits have been adjusted
press Eto return to the 'SPAn' prompt,
followed by Eto return to the main menu.
6.9 Conditioning sub-menu: Cond
This sub-menu allows the mains (line)
frequency at which the instrument has
maximum ac rejection to be selected and the
two internal references to be calibrated. To
minimise the possibility of accidental
adjustment these functions are contained in
a protected sub-menu. To gain access to
this sub-menu select 'Cond' from the main
menu and press Pwhich will cause the
instrument to display '0000'. Using the Up,
and Down buttons and the Pbutton to move
to the next digit, enter the password 'SurE'.
'S' is entered as '5'. Pressing Ewill then
give access to the sub-menu.
6.9.1 AC rejection: FrE
WARNING
If the mains filter frequency is
changed, the rate display and the
internal references (if used) must be
recalibrated.
To provide maximum low frequency rejection
the internal digital filter may be set to
operate at 50 or 60Hz to correspond with the
local mains (line) frequency. To change the
frequency select 'FrE' from the 'Cond' sub-
menu and press Pwhich will reveal the
current setting. The setting can be changed
by pressing the Up or Down buttons followed
by the Ebutton to return to the sub-menu.
6.9.2 Calibration of internal references:
rEF
The BA358C contains two references
representing 4 and 20mA. These are used
in the 'SEt' function that enables the rate
display to be calibrated without an external
current calibrator. They are also used in the
'C--P' function when the Ppush-button is
programmed to display the input current in
the operating mode. If either of these two
functions are used, the internal references
should be routinely calibrated against an
external 4/20mA calibrator connected to the
input terminals of the instrument. See
section 8.4
To calibrate the internal references select
'rEF' from the sub-menu and press Pwhich
will result in a '.004A' prompt being
displayed. Adjust the external current
calibrator to 4.000mA and again press P.
The instrument will display 'Ent' while the
4mA reference is being updated and will
then return to the '.004A' prompt.
To re-calibrate the 20mA internal reference,
press the Up button which will cause the
instrument to display '.020A'. Adjust the
external current calibrator to 20.000mA and
again press P. The BA385C will display
'Ent' while the 20mA reference is being
updated and will then return to the '.020A'
prompt. This completes calibration of the
internal references, two operations of the E
button will return the instrument to the 'Cond'
prompt in the main menu.
6.10 Resetting grand total: CLr. Gtot
The grand total is a separate sixteen digit
counter which duplicates the total display,
but is not zeroed when the total display is
reset to zero. The grand total may be

16
viewed in the operating mode in two eight
digit sections as described in section 2.1 of
this manual.
The grand total counter can only be reset to
zero from the 'CLr.Gtot' function within the
main programme menu. To zero the grand
total counter select 'CLr. Gtot' and press P
which will cause the instrument to display
'Clr. no' with 'no' flashing. Press the Up or
Down button until 'CLr. YES' is displayed
followed by Pwhich will result in a '0000'
prompt. Using the Up and Down buttons
and the Pbutton to move to the next digit,
confirm the request by entering the
password 'SurE'. Note 'S' is entered as '5'.
Pressing Ewill then reset the grand total
counter to zero and return the instrument to
the 'CLr. Gtot' prompt in the main menu.
WARNING
After resetting the grand total counter
to zero the old grand total can not be
recovered.
6.11 Timebase: t-bASE
Together with the total scale factor 'SCALE-
t', this function defines the arithmetic
relationship between the rate and total
displays. The timebase divides the rate
display by 1, 60 or 3,600 depending upon
whether the BA358C rate display represents
flow per second, per minute or per hour.
See Fig 6.
To check or change the timebase select
't-bASE' from the main menu and press P
which will reveal the current setting.
Pressing the Up or Down buttons will index
though the following three options.
BA358C
Rate
display
represents
flow
Select
In
t-base
menu
Total display
= rate
divided by
Per second tb – 1 1
Per minute Tb – 60 60
Per hour Tb – 3600 3600
Select the required divisor and press Eto
return to the main menu.
6.12 Function of the Ppush-button:
C - - P
This parameter defines the function of the P
push-button when the BA358C is in the
display mode. Either the input current in
milliamps or the input as a percentage of
span may be shown.
To check or change this parameter select 'C
- -P' from the main menu and press Pto
reveal the current setting. Pressing the Up
or Down button will toggle the instrument
between the two options. Select '4-20' if the
input current in milliamps is required, or 'PC'
if the input as a percentage of span is
required. When the required option is
displayed press Eto store the selection and
return to the main menu.
Accuracy of both these options depends
upon the accuracy of the internal references
which should be periodically calibrated - see
section 6.9.2
6.13 Total scale factor: SCALE-t
Together with the timebase 't-bASE', this is a
dividing factor which defines the arithmetic
relationship between the rate and total
displays. The total scale factor may be set
to any value between 0.0001 and 65535*
allowing the total flow and rate of flow to be
displayed in different engineering units.
SCALE-t = Units of rate display
Units of total display
When calculating SCALE-t the required units
of measurement for the total display must be
converted to those used for the rate display
as shown in following example:
The BA358C rate display represents litres
per second but the total flow display is
required in UK gallons. There are 4.5461
litres in a UK gallon.
SCALE-t = Units of rate display
Units of total display
= 1 litre = 1 litre
1 gallon 1/(4.5461) litres
SCALE-t = 4.5461

17
Alternatively if the total display is required in
thousand of UK gallons
= 1 litre = 1 litre
1 gallon 1/(4546.1) litres
SCALE-t = 4546.1
The total scale factor SCALE-t is not
dependent on the rate display units of time.
i.e. flow units per second, minute or per
hour. The timebase t-bASE accounts for
these differences.
To check or change the total scale factor
select 'SCALE-t' from the main menu and
press Pto reveal the existing setting, one
digit will be flashing. The value of the
flashing digit can be changed by pressing
the Up or Down buttons. When this digit is
correct pressing Pwill transfer control to the
next digit.
To position the decimal point, move the
flashing digit to the left hand side of the
required decimal point position and
simultaneously press the Up and Down
buttons.
When the required total scale factor has
been entered, press E to store the number
and return to the main menu.
*Note: The maximum numerical value of
SCALE-t is 65535 irrespective of the decimal
point position. i.e. 6.5535; 65.535; 655.35;
6553.5 and 65535.
6.14 Percentage Clip-off: CLIP-OFF
To prevent errors resulting from the
totalisation of very low flow rates over long
periods, the BA358C rate display can be
forced to zero when the flow rate falls below
a specified value. This threshold may be
adjusted between 0 and 10% of flow for
linear inputs, and between 5 and 10% of
flow for square law inputs linearised by the
root extractor.
To check or change the cut-off point select
'CLIP-OFF' from the main menu and press P
to reveal the current setting. This clip-off
threshold is shown as a percentage of total
flow and may be adjusted in one percent
increments using the Up or Down buttons.
When set as required, press the E button to
enter the revised figure and return to the
main programme menu.
6.15 Local reset of total display:
LOC. rSET
When turned on this function enables the
operator to reset the BA358C total display to
zero by operating the Up and Down push-
buttons simultaneously. To check the
status of the function select 'LOC. rSET''
from the menu and press P. If required
press the Up or Down button to change the
setting, followed by the Ebutton to return to
the main menu.
6.16 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. The current
security code will be displayed which may 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 Eto return to the main
menu. The revised security code will be
activated when the indicator is returned to
the display mode.
If the security code is lost, access to the
programmable functions can be obtained by
moving the internal security link to the
override position. The original security code
can then be viewed by selecting 'CodE' from
the main menu and pressing P.

18
Fig 8 Location of security code override
link
To gain access to the security code link,
remove the instrument terminal block(s) by
gently pulling. Remove the six screws
securing the rear panel, and lift off the panel
which will reveal the link - see Fig 8.
6.17 Over and under-range
If the rate display range is exceeded, the
four least significant digits will be blanked.
Under-range is indicated by a flashing '-1'
and over-range by a flashing '1'. Under and
over-range are also indicated if the input
current falls below approximately 3.6mA or
rises above approximately 21mA.
If the input current falls below approximately
3mA, the instrument initialisation sequence
is performed as described in section 2.
When the total display exceeds 99999999 it
will automatically roll-over to zero and
continue counting. The most significant
eight digits of the grand total counter can
count the number of times the total display
rolls-over. If it is anticipated that in normal
operation the total display will exceed
99999999, the grand total should be reset to
zero during commissioning. Up to 108roll-
overs can be counted.
7. CALIBRATION EXAMPLES
This section includes two examples
illustrating how a BA358C rate totaliser may
be programmed and calibrated to display the
rate of flow and total flow measured by a
flowmeter with a 4/20mA output. Section 7.1
describes the preferred method of calibration
using an external traceable 4/20mA
calibrator. Section 7.2 contains an
example of calibration using the BA358C
internal 4 and 20mA references, which
although not traceable, are adequate for
many industrial applications.
7.1 Calibration example
Using an external current source
In this example the BA358C rate totaliser is
connected to a flowmeter having an output
of 20mA at a flow of 1100 litres / minute.
The BA358C is required to display flow in
litres per minute and total flow in cubic
metres with a resolution of 0.1 cubic metres.
Totalisation is to occur for flow rates
between 1 and 100% of maximum flow. The
frequency of the mains supply is 50Hz and a
security code of 1209 is required. In the
operating mode the BA358C is required to
display the input current as a percentage of
span when the P push-button is operated.
Step 1 Connect instrument to calibrator
Connect the BA358C to an accurate
current source such as a calibrator.
Terminal 1 positive and terminal 3
negative. The instrument will
perform the initialisation routine
described in section 2, and then
display the input current on the rate
display using the existing calibration
information.
Step 2 Enter the programming mode
With an input current between 4 and
20mA put the instrument in the
programming mode by
simultaneously pressing Pand E.
Assuming a security code has not
already been entered the instrument
will respond by displaying 'root'
which is the first function in the main
menu. See Figs 7A and 7B.

19
Step 3 Turn square root extractor off
With 'root' displayed, press P which
will reveal the root extractor status.
The root extractor can be turned on
or off by operating the Up or Down
buttons. Select 'OFF', and press E
to return to the 'root' prompt in the
main menu.
Step 4 Select frequency of maximum
mains (line) rejection
Scroll though the main menu until
'Cond' is displayed; press Pwhich
will result in the instrument
displaying '0000' with the most
significant digit flashing. To prevent
accidental adjustment the Cond sub-
menu is protected by the code word
'SurE'' which must be entered
character by character using the Up
and Down buttons plus Pto move
control to the next digit. Note: S is
entered as 5. When 'SurE' has been
entered pressing E will result in the
'FrE' prompt. Press Pto enter the
function and using the Up or Down
buttons select '50'. Finally, press E
twice to return to the 'Cond' prompt
in the main menu.
Step 5 Define function of Ppush-button
Select 'C--P' from the main menu
and press Pto reveal the function of
the Ppush-button in the operating
mode. Select percentage 'PC' and
return to the main menu by pressing
E.
Step 6 Define rate display resolution
Select 'rESn' from the main menu
and press Pto reveal the current
resolution of the rate display. Using
the Up and Down push-buttons
select a resolution of '1' and return to
the 'rESn' prompt in the main menu
by pressing E.
Step 7 Position rate & total decimal
points
Select 'd.P.' from the main menu and
press P. The rate and total displays
will be activated with one digit of the
total display flashing. Press the Up
or Down push-button until the
second least significant digit and
following decimal point of the total
display flash. This gives the
required total display resolution of
0.1
Press Pto move control to the rate
display. Using the Up or Down push-
button move the flashing digit to the
least significant position (right hand
side) which will result in no decimal
point in the rate display.
Finally press Eto return to the 'd.P’.
prompt in the main menu.
Step 8 Calibrate the rate display
Scroll through the main menu until
'CAL' is displayed. Press Pand the
instrument will request a 4mA input
by displaying 'ZErO'. Set the input
current from the external calibrator
to 4.0000mA and press P again
which will reveal the existing rate
display. Using the Up, Down and P
push-buttons enter the required zero
display of 0000 Press Eto enter
this calibration figure and return the
instrument to the 'ZErO' prompt.
Press the Up push-button and the
instrument will request a 20mA input
by displaying 'SPAn'. Set the input
current from the external calibrator
to 20.0000mA and again press P
which will reveal the existing rate
display at 20mA. Using the Up,
Down and Ppush-buttons enter the
required display of 1100
Press Etwice to enter this
calibration figure and return the
instrument to the 'CAL' prompt in
the main menu.
Step 9 Define the timebase
In this example the rate display
represents flow per minute so it is
necessary to set the instrument
timebase to 60. This will divide the
rate display by 60 to provide the
correct total display.
Select ‘t-bASE’ from the main menu
and press Pto reveal the current
setting. Using the Up or Down
button select ‘tb – 60’ and press Eto
return to the main menu.

20
Step 10 Define the total scale factor
In this example the rate display is
in litres per minute but the total
display is required in cubic metres:
SCALE-t = Units of rate display
Units of total display
There are 1,000 litres in a cubic
metre thus:
= litres
cubic metres
= 1 litre
1/(1000) litres
SCALE-t = 1000
From the main menu select
'SCALE-t' and press Pto reveal
the current five digit dividing factor.
Using the Up and Down buttons to
adjust the flashing digit, and the P
button to transfer control between
digits, set 'SCALE-t' to 1000.0
The position of the decimal point is
defined by moving the flashing digit
to the second least significant
position and operating the Up and
Down buttons simultaneously.
When 'SCALE-t' has been set to
1000.0 press Eto return to the
main menu.
Step11 Define percentage cut-off
Totalisation is to be inhibited at
flow rates below 1% of maximum
flow. To define this cut-off point
select ‘CLIP-OFF' from the main
menu and press Pwhich will reveal
the current setting. Using the Up
and Down buttons select 1 and
return to the main menu by
pressing E.
Step 12 Reset the grand total to zero
To reset the grand total to zero
select 'CLr. Gtot' from the main
menu and press Pwhich will cause
the instrument to display 'Clr. no'.
Toggle this to 'CLr. YES' using the
Up or Down push-buttons and
press Pwhich will result in a '0000'
prompt. Using the Up, and Down
buttons and the P button to move
to the next digit, enter the
password 'SurE' which protects
this function. Pressing Ewill then
reset the grand total counter to
zero and return the instrument to
the 'CLr. Gtot' prompt in the main
menu.
Step 13 Set the security code
Defining a security code prevents
unauthorised access to the
programme functions. Select
'COdE' from the main menu and
press Pwhich will reveal the
existing security code. Using the
Up and Down buttons enter the
new code 1209 digit by digit. The
Pbutton will transfer control
between digits. When the new
code has been entered, press Eto
return to the main programme
menu.
Step 14 Return to the display mode
Following completion of
programming and calibration,
return the instrument to the
operating mode by pressing E. All
the BA358C programming
functions will now be stored in
permanent memory and protected
from accidental adjustment by the
security code.