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7. CALIBRATION EXAMPLE
In this example a BA334D rate totaliser is
connected to a turbine flowmeter having a K-
factor of 1050.0 pulses per litre. The
flowmeter has a magnetic pick-off with a peak
output greater than 20mV at 5 litres per minute
and a usable range of 5 to 60 litres per minute.
The BA334D is required to display rate of flow
in litres per hour with a resolution of one litre
and total flow in cubic metres with a resolution
of 0.01 cubic metres. Totalisation is to stop
when the flow rate falls below 300 litres per
hour. The display is to be updated twice per
second and filtering is required. In this
application the operator needs to reset the total
display to zero by simultaneously pushing the
Up and Down push-buttons. To prevent
tampering the instrument programme menu is
to be protected by security code 1209
7.1 Calibration procedure
The BA334D rate totaliser may be calibrated
on-site without disconnection from the power
supply or from the flowmeter.
Step 1
Enter the programming mode
Put the BA334D in the
programming mode by
simultaneously pressing P and E.
Assuming a security code has not
already been entered the
instrument will respond by
displaying 'UPdAtE' which is the
first function in the main menu.
See Fig 9.
Step
2
Select the interval between
display updates
With 'UPdAtE' displayed, press P
to reveal the existing interval
between display updates. If this is
not as required, press the Up or
Down button until ‘0.5’ is displayed.
(0.5 seconds i.e. 2 display updates
per second). Enter the revised time
and return to the 'UPdAtE' prompt
in the main menu by pressing E.
Step 3
Select the type of input
Using the Up 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 BA334D has two pairs of
input terminals. 3 & 4 for voltage
inputs and 5 & 6 for switch contact,
proximity detector or open collector
inputs. Ensure that the magnetic
pick-off that has a voltage output is
connected to terminals 3 & 4.
Step
4
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 third least significant digit
of the total display and following
decimal point are flashing. This
gives the required total display
resolution of 0.01
Press P to 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 being displayed.
Finally press E to return to the 'd.P’.
prompt in the main menu.
Step 5
Enter the rate scaling factor
Select ‘SCALE-r’ from the main
menu and press P to show the
current figure. The K factor of the
flowmeter in this example is
1050.0* pulses per litre which
should be entered as the rate
scaling factor.
Firstly to position the decimal point,
operate the P push-button to move
the flashing digit to second least
significant position. Pressing the
Up and Down buttons
simultaneously will then position the
decimal point in front of the least
significant digit.
Using the Up and Down buttons to
adjust each digit in turn and the P
button to transfer control between
digits, enter 1050.0 Finally return
to the 'SCALE-r' prompt in the main
menu by pressing E.
* Could also be entered as 1050
Summary of Contents for BA334D
Page 12: ...12 Fig 7 Dimensions and terminal connections ...
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