background image

24

The pulse output will sink up to 10mA. When
closed the voltage between the pulse output
terminals P1 & P2 will be less than 3V when
switching 5mA.

Fig 14  Typical application of pulse output

8.6  4/20mA output

The optional 4/20mA output may be programmed
to produce an analogue output proportional to the
whole or part of the rate display.   The output is a
current sink which requires between 5 and 30V to
function as shown in Fig 15.

Fig 15  Application of 4/20mA output

8.6.1 

Programming and adjustment

The main programme menu is extended as shown
in Fig 16 to accommodate the 4/20mA calibration
functions.

The ‘4-20 OP’ programme function allows the
4/20mA output current to correspond to any rate
display.  e.g.  4mA could represent 10
litres/minute and 20mA  100 litres/minute.

To calibrate the 4/20mA output current, enter the
programme mode by operating the 

P

 and 

E

 push-

buttons simultaneously.   If the instrument is not
protected by a security code the first parameter
‘UPdAtE’ will be displayed.   Enter the security
code if the instrument is protected.

Using the 

Up

 or 

Down

 push button select the

function ‘4-20 OP’ and press 

which will result in

the BA538C displaying ‘4.000’ which is the prompt
for setting the rate display corresponding to an
output current of 4.000mA.   Pressing 

P

 will reveal

the existing setting with the most significant digit
flashing.  The decimal point will be fixed in the
position already defined for the rate display by the
‘d.P’ function.   The value of the flashing digit may
be changed by pressing the 

Up

 or 

Down

 buttons.

When this digit is set as required, pressing 

P

 will

transfer control to the next digit.

When the flow rate corresponding to an output
current of 4mA has been entered, press the

  E

button to return to the ‘4.000’ prompt.

To enter the rate display corresponding to an
output current of 20.000mA, press the 

Up

 or 

Down

button to select the ’20.000’ prompt followed by 

P

to 

reveal the current setting.  This may be

changed in the same way as the 4mA setting.
When set as required, press 

E

  three times to

return to the display mode via the ‘20.000’ and ‘4-
20 OP’ prompts.

The 4/20mA output may be calibrated to increase
or decrease as the rate display increases, and
most instruments will produce a linear output
between 3.5 and 22mA.

Note 1:  

If the rate display calibration is changed

by adjusting the rate scale factor SCALE-r, the
timebase t-bASE, or the position of the rate
display decimal point, the 4/20mA output will
automatically be set to give a constant 3.5mA
output irrespective of the rate display.   The
4/20mA output must therefore always be
recalibrated following recalibration of the rate
display.

Содержание BA538C

Страница 1: ...ssue 12 25th March 2014 Label information Rate display Annunciators for optional alarms Rotating flow indicator Total display BA538C Externally powered pulse input panel mounting rate totaliser issue 12 ...

Страница 2: ...otal 5 15 Security code 6 Calibration Example 6 1 Calibration procedure 7 Maintenance 7 1 Fault finding during commissioning 7 2 Fault finding after commissioning 7 3 Servicing 7 4 Routine maintenance 7 5 Guarantee 7 6 Customer comments 8 Accessories 8 1 Scale card 8 2 Tag number 8 3 Alarms 8 3 1 Solid state output 8 3 2 Programming and adjustment 8 3 3 Alarm enable 8 3 4 Type of alarm 8 3 5 Setpo...

Страница 3: ...unction on the rate or total displays further extend the instrument s applications Fig 1 Simplified block diagram of BA538C 2 1 Initialisation Each time power 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 2 seconds The product firmware number and the version number are displayed...

Страница 4: ...et Activated when the instrument Annunciator is being reset 3 SYSTEM DESIGN 3 1 Flow transmitter loops The BA538C may be connected to almost any pulse output flowmeter and calibrated to display rate of flow and total flow in the same or different engineering units Fig 2 illustrates the basic circuit that is used for all BA538C installations For simplicity connections for the optional pulse output ...

Страница 5: ...y be used as an inhibit function There is no practical limit on the distance that the reset switch may be from the totaliser Alternatively the BA538C may be programmed so that the total display is reset to zero when the Up and Down push buttons are operated simultaneously for more than two seconds see 5 12 4 INSTALLATION 4 1 Location The BA538C is housed in a robust aluminium enclosure with a poly...

Страница 6: ...closure and the panel c Connect the panel wiring to the rear terminal block s as shown in Fig 4 To simplify installation the terminals are removable so that panel wiring can be completed before the instrument is installed Fig 4 Installation and terminal connections 4 3 EMC The BA538C complies with the requirements of the European EMC Directive 2004 108 EEC For specified immunity all wiring should ...

Страница 7: ...l decimal points Moving the position of a decimal point in a scale factor will therefore affect the instrument calibration The BA538C updates its total flow calculation twice per second If the instrument is used for batching applications this resolution may define the accuracy of the system Note The total and rate displays may be updated less frequently depending upon the display update time selec...

Страница 8: ...8 ...

Страница 9: ...LAY 2 Lower display Turns the lower display which normally shows rate on or off See section 5 7 Display Description of function SCALE r Rate Scale Factor Defines the arithmetic relationship between the pulse input frequency and the rate display May be adjusted between 0 001 and 99999999 When used with a flowmeter SCALE r should be set to the flowmeter K factor pulses per unit of measurement if the...

Страница 10: ... current input type Pressing Up or Down will scroll through the five options UOLts Voltage pulse input Threshold 1V and 3V 5kHz max Input terminals 3 and 4 COIL Low voltage pulse Threshold 20mV peak 5kHz max Input terminals 3 and 4 Pr dEt NAMUR proximity detector Threshold 1 2 and 2 1mA 5kHz max Input terminals 5 and 6 COntACt Switch contact Threshold 100 and 1000 100Hz max Input terminals 5 and 6...

Страница 11: ...te display by 1 60 or 3 600 depending upon whether the BA538C is required to display rate per second per minute or per hour See Fig 5 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 button will index through the three options tb 1 for flow second tb 60 for flow minute tb 3600 for flow hour Select the require...

Страница 12: ... rates that over long periods may result in significant totalisation errors the BA538C may be programmed to stop totalising when the flow rate falls below an adjustable threshold To check or change the clip off threshold select CLIP OFF from the main menu and press P which will reveal the current setting The threshold is shown in the units already selected for the flow rate display One digit will ...

Страница 13: ...re 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 without entering a security code To enter a new security code select COdE from the menu and press P which will cause the instrument to display the current security code Each digit of the code can be changed using the Up and Down...

Страница 14: ...p or Down button scroll through the main menu until InPut is displayed then press P to reveal the existing setting Select COIL the input for a magnetic pick off using the Up or Down button and return to the InPut prompt in the main menu by pressing E Note The BA538C has two pairs of input terminals 3 4 for voltage inputs and 5 6 for switch contact proximity detector or open collector inputs Ensure...

Страница 15: ... metre for every 1 050 x 1 000 pulses received SCALE t should therefore be set to 1 050 000 Select SCALE t from the main menu and press P which will reveal the current setting with one digit flashing To position the decimal point operate the P push button to move the flashing digit to the least significant position Pressing the Up and Down buttons simultaneously will then remove the decimal point ...

Страница 16: ...strument to the CLr Gtot prompt in the main menu Step 12 Define the security code Defining a security code prevents unauthorised access to the programme functions Select COdE from the main menu and press P which will reveal the existing security code Using the Up and Down buttons enter the new code 1209 digit by digit The P button will transfer control between digits When the new code has been ent...

Страница 17: ...ation Alarms do not function Alarms have been disabled following calibration change Re enable both alarms 7 2 Fault finding after commissioning ENSURE PLANT SAFETY BEFORE STARTING MAINTENANCE If a BA538C fails after it has been functioning correctly the following table may help to identify the cause of the failure Symptom Cause Check No display No power supply That there is between 10 and 30Von te...

Страница 18: ...ons such as a shut down system When the BA538C power supply is turned off or disconnected both BA538C alarm outputs will open irrespective of whether normally open or normally closed outputs have been selected When designing a system an open output should therefore be the alarm condition Alarm annunciators on the instrument display indicate the status of both alarms If an alarm delay or silence ti...

Страница 19: ...rm operates on the rate or total display See section 8 3 4 SPr1 Alarm setpoint 1 or Adjusts the alarm setpoint The SPt1 alarm is activated when the rate or total display equals the setpoint Note SPr1 is displayed for a rate alarm and SPt1 for a total alarm See section 8 3 5 HI LO Alarm function Defines whether the alarm has a high or low function See section 8 3 6 no nc Normally open or normally c...

Страница 20: ...ed or the alarm type has been changed Both alarms must therefore be enabled after calibration changes 8 3 4 Type of alarm tYPE Alarm 1 and Alarm 2 may both be rate or total alarms or one may be conditioned for rate and the other for total To check or change the type of alarm select tYPE from the alarm menu and press P which will reveal the current setting The function can be changed by pressing th...

Страница 21: ...eresis select HStr from the alarm menu and press P which will reveal the existing figure Each digit can be adjusted using the Up and Down push buttons and the P button to move to the next digit When the required hysteresis has been entered press E to return to the alarm menu e g A BA538C calibrated to display a flow of 0 to 5000 with a high alarm set at 4000 and hysteresis of 100 will perform as f...

Страница 22: ...to the setpoints in the display mode by pressing the P and Up buttons simultaneously New instruments with alarms are supplied with the security code set to 0000 8 3 12 Adjusting alarm setpoints from the display mode Access to the two alarm setpoints from the instrument display mode is obtained by operating the P and Up push buttons simultaneously as shown in Fig 11 If the setpoints are not protect...

Страница 23: ...g 12 Display backlight 8 5 Pulse output The BA538C may be supplied with an opto isolated solid state pulse output The output is a polarised current sink that closes for a programmable duration each time the least significant digit of the BA538C display changes A programmable divider enables the pulse output frequency to be divided by 10 100 1 000 or 10 000 See Fig 13 The output pulse is not synchr...

Страница 24: ...isplay corresponding to an output current of 4 000mA Pressing P will reveal the existing setting with the most significant digit flashing The decimal point will be fixed in the position already defined for the rate display by the d P function The value of the flashing digit may be changed by pressing the Up or Down buttons When this digit is set as required pressing P will transfer control to the ...

Страница 25: ...output are powered from separate supplies the 4 20mA output current will continue to flow when the BA538C supply fails or is turned off Powering both from a common supply as shown in Fig 15 eliminates this effect Fig 16 4 20mA output programme structure ...

Страница 26: ...5 4 dISPLAY 2 5 7 d P 5 6 EnbL 8 3 2 8 3 3 Fault finding during commissioning 7 1 after commissioning 7 2 FILtEr 5 10 Flow indicator 2 3 Grand total 2 3 clear 5 14 Guarantee 7 5 HI LO 8 3 2 8 3 6 HStr 8 3 2 8 3 8 InPut 5 5 Installation 4 2 Subject Section LOC rSEt 5 13 Local reset 5 13 Location 4 1 Maintenance 7 0 routine 7 4 no nc 8 3 2 8 3 7 Output Pulse 8 5 4 20mA 8 6 Push buttons Down 2 2 E 2 ...

Отзывы: