15
6. CALIBRATION EXAMPLE
In this example a BA544D rate totaliser is
connected to a turbine flowmeter having a K-
factor of 105.0 pulses per litre. The flowmeter
has a magnetic pick-off with a peak to peak
output greater than 40mV at 1 litre per minute
and a usable range of 1 to 40 litres per minute.
The BA544D 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 1 litre per
minute. To maximise battery life, the display is
to be updated once every twenty seconds.
Rate display 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
6.1 Calibration procedure
The BA544D 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 BA544D 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 7.
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 ‘20’ is displayed.
(i.e. the display is updated once
every twenty seconds). 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 BA544D has two pairs of
input terminals. 3 & 4 for voltage
inputs and 5 & 6 for switch contact
and open collector inputs. Ensure
that the magnetic pick-off, which
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 105.0*
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 the 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 105.0 Finally return
to the 'SCALE-r' prompt in the main
menu by pressing
E
.
* Could also be entered as 105
Summary of Contents for BA544D
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