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6.20  Pulse output

The BA314NG Tachometer has an opto-isolated open
collector  pulse  output  with  following  electrical
parameters:  

Ron

=

60

 + 3V

Roff

=

1M

I max

=

10mA

The output pulse may be a synchronous duplicate of
the input pulse or may be scaled and the pulse length
extended.

The retransmitted RTx annunciator on the instrument
display  shows  the  status  of  the  retransmitted  pulse
output.    Annunciator  activation  depends  upon  the
setting  of  

5ource

  in  the  pulse  output  configuration

menu. 

5caled:

Annunciator  activated  each  time  pulse  output
open collector is 

on

,   i.e. Ron is less than 60

+ 3V. 

direct:

Annunciator

 

continuously activated

6.20.1  Ex nA certification

The  pulse  output  is  a  separate  opto-isolated  Ex nA
circuit with the following input safety parameters:

Ui

=

30V dc

Ii

=

100mA

This allows the pulse output to be connected to any dc
circuit providing that in normal operation the maximum
supply voltage is not greater than 30V dc.  

Providing  the  BA314NG  Tachometer  is  correctly
installed in Zone 2, the pulse output may be directly
connected  to  any  suitably  protected  equipment
located  in  Zone  1  or  2  of  a  hazardous  area,  or  to
equipment located in a safe area.    The pulse output
should not be directly connected to intrinsically safe
equipment.

Fig  11  shows  a  BA314NG  Tachometer  mounted  in
Zone 2  retransmitting a pulse to the safe area.   The
current pulse flows through R1 resulting in a voltage
pulse output with an amplitude of about 20V. 

To  comply  with  the  requirements  of
EN 60079-14

 Electrical installations design, selection

and  erection

,   each   of   the   wires   entering   the

hazardous  area  should  be  individually  fused  and
contain a means of isolation.  These two requirements
may  be  satisfied  by  installing  DIN  rail  mounted
terminals  incorporating  a  fuse  which  can  easily  be
removed as shown in Fig 2 to provide isolation.  Clear
identification  of,  and  easy  access  to  the  means  of
isolation is essential for their effective use. It is also
necessary to ensure that the maintenance procedure
makes  sure  that  unauthorised  re-closure  of  the
switches  does  not  occur.    It  is  not  considered

necessary to have a means of isolation or electrical
protection for cable screens.

For  some  applications  Ex nA  instrumentation
energised  by  a  current  limited  power  supply  or
instrument  that  can  be  switched  off,  is  often
considered  adequate  and  to  comply  with  the
requirements of the standard.

6.20.2  System design

The Tachometer’s pulse output is a passive circuit
i.e.  not  powered,  but  it  is  totally  isolated  from  all
other  Tachometer  circuits.      Subject  to  complying
with  Ex nA  interconnection  requirements,  the
terminals P1 and P2 may be connected to any other
instrument with an open collector pulse input.   

Fig 11 shows how to produce a voltage pulse in the
safe area that could be used to drive a safe area
counter.    The positive terminal of the pulse output
circuit P1 is connected to the Tachometer’s positive
supply terminal 1.  When an output pulse occurs and
the  open collector output ‘closes’, P2 is connected
to P1 and the pulse current flows through resistor R1
in the safe area.   The current flowing in the circuit is
determined by R1 which should be chosen to limit
the pulse output current to less than 10mA.  For a
24V supply R1 should be greater than 2,200

.  

Fig 11 Transferring pulse output to the safe area

22

Содержание BA314NG

Страница 1: ...Issue 5 9th July 2019 BA314NG Ex nA and Ex tc Tachometer Issue 5...

Страница 2: ...dAtE 6 8 Run time display di5P 2 6 9 Position of the decimal points dP 6 10 Speed scale factor 5CALE 5 6 11 Timebase t bA5E 6 12 Display filter FiLtEr 6 13 Clip off CLP oFF 6 14 Local reset LoC clr 6...

Страница 3: ...larm silence time 5IL 9 3 12 Flash display when alarm occurs FL5H 9 3 13 Access Setpoint AC5P 9 3 14 Adjusting alarm setpoints from the display mode 9 4 4 20mA output 9 4 1 Ex nA certification 9 4 2 S...

Страница 4: ...m compliance with the European ATEX Directive 2014 34 EU For international applications the BA314NG also has IECEx certification which is described in Appendix 2 For applications in the USA and Canada...

Страница 5: ...the Tachometer may be configured to provide direct access to the alarm setpoints from the display mode when the and buttons are operated simultaneously See 9 3 13 and 9 3 14 2 3 Displays The BA314NG...

Страница 6: ...the Type Examination Certificate This allows the Tachometer to be adjusted and configured live when installed in Zones 2 When connected to a suitable system the BA314NG Tachometer may be installed in...

Страница 7: ...ety parameters Input Output Type of input Link 3 4 Ui Uo Io Switch contact Yes 15V 10 5V 9 2mA Proximity detector Yes 15V 10 5V 9 2mA Open collector Yes 15V 10 5V 9 2mA Magnetic pick off No 30V 1 1V 0...

Страница 8: ...that terminals 2 6 and RS2 are interconnected within the BA314NG See Fig 1 4 1 Power supply The BA314NG Tachometer requires a minimum of 10V between terminal 1 2 and consumes 10mA without optional bac...

Страница 9: ...eshold and rise above the upper thresholds shown in the following table Input transducer Switching thresholds Lower Upper Open collector 2k 10k Voltage pulse low 1 0V 3 0V Voltage pulse high 3 0V 10 0...

Страница 10: ...d associated wiring should be able to withstand a 500V rms insulation test to earth The BA314NG contains a configurable debounce circuit to prevent false triggering See section 6 6 4 2 6 Voltage pulse...

Страница 11: ...the bottom right hand corner the back box for interconnecting cable screens The BA314NG Tachometer may be pipe mounted using a BA393G pipe mounting kit 5 2 Installation Procedure Fig 6 illustrates the...

Страница 12: ...instrument is ordered a blank scale card will be fitted which can easily be marked on site with a dry transfer or a permanent marker Custom printed scale cards are available from BEKA associates as a...

Страница 13: ...factor that determines whether the Tachometer displays speed per second per minute or per hour The Tachometer incorporates a run time counter that displays the time in hours that the speed of the mon...

Страница 14: ...on or oFF See section 6 8 Display Summary of function dP Decimal points Defines the position of the decimal point in the Tachometer speed display See section 6 9 5CALE 5 Speed scale factor 5CALE 5 is...

Страница 15: ...6 Display Summary of function CLr Gtot Resets grand total run time to zero This function resets the grand total run time to zero from within the configuration menu when CLr YE5 is selected and 5urE is...

Страница 16: ...16...

Страница 17: ...17...

Страница 18: ...ges such as those resulting from a mechanical contact closing and bouncing Three levels of protection may be selected and the amount of debounce applied depends upon the type of Tachometer input that...

Страница 19: ...g shaft generates 18 pulses per revolution to produce a Tachometer speed display in revolutions 5CALE 5 should be set to 18 0 The units of the Tachometer speed display are pulses per unit of time The...

Страница 20: ...sed it is not necessary to enter a clip off value see 6 8 To check or change the clip off threshold select CLP oFF from the configuration menu and press which will reveal the current setting The thres...

Страница 21: ...isplayed and then press which will result in a 0000 prompt being displayed with the first digit flashing This is a request for the instruction to be confirmed by entering 5urE using the or button to a...

Страница 22: ...the wires entering the hazardous area should be individually fused and contain a means of isolation These two requirements may be satisfied by installing DIN rail mounted terminals incorporating a fus...

Страница 23: ...ting on or oFF The function can be changed by pressing the or push button followed by the button to return to EnbL prompt in the sub menu 6 20 6 Source of output pulse 5ourCE The output pulse may be d...

Страница 24: ...to select the required value followed by the button to return to durAtion prompt in the sub menu Note This function only appears in the pulse output sub menu when 5CALEd is selected in the 5ource sub...

Страница 25: ...al between display updates Using the or button select uPdAtE in the configuration menu and press to reveal how frequently the Tachometer display is updated Using the or push button select 0 5 0 5 seco...

Страница 26: ...h buttons The button will transfer control to the second digit which controls the step response and should be set to 0 in the same way Finally enter the selection and return to the FiLtEr prompt in th...

Страница 27: ...s unauthorised access to the configuration menu Using the or button select CodE from the configuration menu and press which will reveal 0000 with the first digit flashing This example requires the sec...

Страница 28: ...ion change Re enable both alarms See 9 3 4 8 2 Fault finding after commissioning EN 60079 17 Electrical installations inspection and maintenance permits live maintenance in Zone 2 if a risk analysis d...

Страница 29: ...your local BEKA agent It is helpful if a brief description of the fault symptoms is provided 8 6 Customer comments BEKA associates is always pleased to receive comments from customers about our produ...

Страница 30: ...with factory fitted dual isolated solid state single pole alarm outputs that may be independently configured Each may be configured as a speed or run time alarm with a high or low function having a no...

Страница 31: ...the means of isolation is essential for their effective use It is also necessary to ensure that the maintenance procedure makes sure that unauthorised re closure of the switches does not occur It is n...

Страница 32: ...t and the alarm output being activated See section 9 3 10 5IL Alarm silence time Defines the time that the alarm output remains in the non alarm condition following acceptance of an alarm See section...

Страница 33: ...to return to the alarm sub menu 9 3 5 Type of alarm tYPE Alarm 1 and Alarm 2 are totally independent both may be speed or run time alarms or one may be conditioned for speed and the other for run time...

Страница 34: ...ggle the contact status between no and nC when set as required press the button to return to the no nC prompt in the alarm sub menu 9 3 9 Hysteresis H5tr Hysteresis is only available on speed alarms s...

Страница 35: ...l adjustment is provided by a separate security access code Using the or push button select AC5P from the configuration menu and press to reach the enable function EnbL Pressing will reveal the existi...

Страница 36: ...the or push button and the button to transfer control to the next digit When the required setpoint has been entered pressing will return the display to the 5P1x or 5P2x prompt from which the other se...

Страница 37: ...ed and contain a means of isolation These two requirements may be satisfied by installing DIN rail mounted terminals incorporating a fuse which can easily be opened as shown in Fig 2 to provide isolat...

Страница 38: ...g the or push button select 4 000 in the 4 20mA output sub menu and press to reveal the existing speed display with one digit flashing The required display can be entered using the or push button to a...

Страница 39: ...cate indicated by the certificate number s X suffix These state that the BA314NG Tachometer should be a Supplied from a limited energy circuit with output parameters in normal operation equal to or le...

Страница 40: ...ical to the ATEX safety parameters described in the main section and in Appendix 1 of this manual The IECEx certificate may be downloaded from the BEKA associates or the IECEx website or may be reques...

Страница 41: ...T5 Gc Zone 22 AEx ic tc IIIC T80 C Dc Ta 40 C to 60 C cETL codes for Canada Ex nA ic IIC T5 Gc Ex n IIC T5 Gc Ex ic tc IIIC T80 C Dc Class III Div 2 Class II Div 2 Gp F G Ta 40 C to 60 C The ETL and...

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