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14

7.

LINEARISER

A sixteen segment, seventeen break-point (0 to 16)
lineariser may be selected in the  

FunC

 section of

the  configuration  menu.    The  position  of  each
break-point is fully adjustable so that the slope of
the straight line between break-points can be set to
compensate  for  input  non-linearity,  thus  allowing
the  indicator  to  display  a  non-linear  process
variables in linear engineering units. Each break-
point  must  occur  at  a  current  greater  than  the
preceding break-point and less than the following
break-point,  in  the range  3.8  to  21.0mA.   If  this
requirement is not observed when configuring the
lineariser  the  indicator  will  display  

FaiL

 and  the

configuration adjustment which produced the error
message will be ignored.  Fig 8 shows a typical
linearised indicator characteristic.

Fig 8 shows a typical linearising characteristic

Selecting  

Lin

 in  the  

FunC

  section  of  the

configuration  menu  activates  the  lineariser,  this
does not change the configuration menu shown in
Fig 7, but the 

CAL

 and 

5Et

 functions are extended

as  shown  in  Fig  9.    As  with  a  linear  indicator,
calibration of the lieariser may be performed with
an external current source using the  

CAL

 function,

or  with  the  internal  reference  using  the  

5Et

function.

The lineariser calibration is retained irrespective of
how  the  indicator  function  

FunC

 is  subsequently

changed.    It  is  therefore  possible  to  select  and
deselect  the  lineariser  without  having  to
reconfigure it each time.

The  lineariser  calibration  may  be  reset  to  the
factory  default  settings  without  changing  the
indicator  configure  using  the  

LtAb

 function

described in section 6.11.

7.1

Lineariser calibration using an external
current source.

This  method  allows  direct  calibration  of  the
lineariser with an external current source and is the
preferred method when traceability is required.   If
the  exact  system  non-linearity  is  unknown,  this
method  also  allows  direct  calibration  from  the
variable to be displayed.  e.g. the output from a
level sensor in an irregular tank may be displayed
in  linear  volumetric  units  by  filling  the  tank  with
known  incremental  volumes  and  calibrating  the
indicator to display the sum of the increments at
each break-point.

The number of break-point required should first be
entered using the  

Add

 and  

dEL

 functions.  In both

these  sub-functions the  indicator initially  displays
the  current  break-point  and  the  total  number  of
break-points being used as shown below.

   Display

      Summary of function              

Add

Add a break-point

Adds  a  new  break-point  before  the
displayed break-point.  The calibration of
existing break-points is not changed, but
the  identification  number  of  all
subsequent break-points is increased by
one.

dEL

Remove a break-point

Removes the displayed break-point and
joins  the  preceding  break-point  to  the
following break-point with a straight line.
The  identification  number  of  all
subsequent break-points is decreased by
one.

To add a break-point use the  

&

 or  

*

 button to

select 

CAL

 from the configuration menu and press

(

 which will result in the 

Add

 sub-function prompt

being displayed.  To enter the sub-function press

(

  which  will  reveal the current break-point and

the  total  number  of  break-points  which  have
already been entered.  When adding a break-point
the insertion position can be selected using the 

&

and  

*

 push buttons followed by  

(

 push button

to  insert the additional break-point.  In previously
uncalibrated  linearisers  each  new  break-point
should  be  added  in  front  of  the  highest  existing
break-point, if this sequence is not followed a 

FaiL

message  will  occur  in  the  

Pt5

 function.   See

example in section 7.1.1.

Summary of Contents for BA304NG

Page 1: ...Issue 4 1st November 2017 BA304NG BA324NG Ex nA Ex tc loop powered field mounting indicators Issue 4...

Page 2: ...tor 7 3 Under and over range 7 4 Lineariser default configuration 8 Maintenance 8 1 Fault finding during commissioning 8 2 Fault finding after commissioning 8 3 Servicing 8 4 Routine maintenance 8 5 G...

Page 3: ...Notified Body Intertek Testing and Certification Ltd which has been used to confirm compliance with the European ATEX Directive 2014 34 EU For international applications both models have IECEx certifi...

Page 4: ...and dust certification This section of the instruction manual describes ATEX gas certification ATEX dust certification is described in Appendix 1 and IECEx approvals are described in Appendix 2 3 1 A...

Page 5: ...to display the measured variable or control signal in engineering units The indicators are transparent to HART signals There are four design requirements 1 The current flowing in the 4 20mA loop must...

Page 6: ...on the rear of the indicator assembly as shown in Fig 5 If the field wiring is to be terminated prior to the installation of the indicator assembly a back box terminal assembly which includes a 4 20m...

Page 7: ...ors are supplied with a printed scale card showing the requested units of measurement and tag information If this information is not supplied when the indicator is ordered a blank scale card will be f...

Page 8: ...r this prompt allowing each digit of the code to be entered using the and push buttons and the button to move control to the next digit When the correct four digit code has been entered pressing will...

Page 9: ...djusted without the need for an accurate input current or disconnection from the 4 20mA loop See section 6 6 bAr Bargraph format and calibration Only the BA324NG has a bargraph The bargraph may be con...

Page 10: ...10...

Page 11: ...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 configuration menu 6 5 Calibration...

Page 12: ...cator s digital display at which the bargraph starts is defined by the bArLo sub function which is selected by pressing the button followed by the button which will reveal the current indicator displa...

Page 13: ...ions shown in sections 6 0 and 7 3 To reset the indicator or lineariser select r5Et from the configuration menu and press the indicator will display one of the reset options ConF or LtAb ConF Resets t...

Page 14: ...ows direct calibration of the lineariser with an external current source and is the preferred method when traceability is required If the exact system non linearity is unknown this method also allows...

Page 15: ...15...

Page 16: ...ng break point 7 1 1 Example Adding break points to a new indicator When adding break points to a new indicator or to a lineariser following resetting to the factory defaults using the LtAb function d...

Page 17: ...n by pressing the button The corresponding indicator display at each of the break points can now be defined using the di5P sub function Using the and buttons select the di5P sub function and press whi...

Page 18: ...o risk of a flammable atmospjher being present If an indicator fails after it has been functioning correctly follow the procedure shown in section 8 1 If this does not reveal the cause of the fault it...

Page 19: ...haracters 5mm high 9 2 Display backlight The BA304NG and BA324NG loop powered indicators can be supplied with a factory fitted backlight that may be loop or separately powered When loop powered the ba...

Page 20: ...s an emergency shut down system Both models can be supplied with factory fitted dual solid state single pole alarm outputs Each alarm output may be independently conditioned as a high or low alarm wit...

Page 21: ...lication in which a BA304NG or BA324NG indicator is displaying the output from a 2 wire transmitter in Zone 2 Alarm 1 is switching a solenoid valve in Zone 2 and alarm 2 is switching a sounder located...

Page 22: ...tpoint The alarm is activated when the indicator display equals the setpoint See section 9 3 5 Hi Lo Alarm function Defines the alarm function as High or Low See section 9 3 6 no nC Normally open or n...

Page 23: ...23...

Page 24: ...e for fail safe operation both alarm outputs should be conditioned to be open in the alarm condition nC To check or change the alarm output status select no nC from the alarm configuration menu and pr...

Page 25: ...t having access to the indicator configuration menu Protection against accidental adjustment of the setpoints when the indicator is in the display mode is provided by a separate security code This dir...

Page 26: ...plus the displayed value to be represented or a low and a high setpoint plus the displayed value to be represented by the bargraph as shown in Fig 18 Fig 18 Displayed value and setpoints on bargraph T...

Page 27: ...supplied with each panel mounting kit 9 6 Back box terminal assembly If it is necessary to terminate the field wiring prior to the installation of the indicator display a back box terminal assembly is...

Page 28: ...o be used for Zone 22 combustible dust applications The indicator should be located where the minimum amount of dust will accumulate on the enclosure and the installation should be as specified in thi...

Page 29: ...USA and Canada A3 0 cETL Mark For installations in the USA and Canada the BA304NG and BA324NG indicators have ETL and cETL Ex nA and Ex tc approval Control Number 4008610 Copies of the Authorisation...

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