BEKA BA534D, Manual

Page: 12 / 26

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During commissioning it is recommend that
initially the second digit is set to 0 (off) and the
first digit is adjusted to provide acceptable rate
display stability. The second digit should then be
increased until the selected step size is greater
than the noise on the display signal, at which
setting the rate display will again become stable.
These will be the optimum filter parameters for
acceptable rate display stability and a fast
response to a large rate signal change.
To check or change the filter select 'FILtEr' from
the main menu and press
P to reveal the current
settings. Pressing the Up or Down button will
change the flashing digit and P will transfer control
to the second digit. While making adjustments the
filtered rate display is shown on the lower display
so that stability can be assessed. When set as
required, press the
E button to enter the revised
parameters and return to the main menu.
5.11 Total scale factor: ‘SCALE-t’
This factor defines the arithmetic relationship
between the number of input pulses and the total
display. SCALE-t is a dividing factor that may be
adjusted between 0.001 and 99999999. See Fig
5.
When used with a flowmeter SCALE-t should be
set to the K-factor of the flowmeter i.e. the
number of pulses the flowmeter produces for a
unit of flow. If the BA534D total display is
required in units different from those in which the
flowmeter K factor is specified, a conversion factor
will be required.
e.g. If the flowmeter has a K factor of 45.6 pulses
per litre and the BA534D total display is required
in units of 1,000 gallons, then SCALE-t should be
set to the number of pulses produced by the
flowmeter per 1,000 gallons:
45.6 x 4.54609 x 1000
207,301.7 pulses per 1000 gallons
.
(there are 4.54609 litres in a UK gallon)
To check or change the total scale factor select
'SCALE-t' from the main menu and press
P to
reveal the existing setting, one digit will be
flashing. The value of the flashing digit can be
changed by pressing the
Up or Down buttons.
When this digit is correct pressing P will transfer
control to the next digit.
To position the decimal point in the scaling factor,
move the flashing digit to the left hand side of the
required decimal point position and
simultaneously press the
Up and Down buttons.
When the required total scale factor has been
entered, press
E t o store the number and return to
the main menu.
5.12 Clip-off: ‘CLIP-OFF’
To prevent totalisation of very low flow rates,
which over long periods may result in significant
totalisation errors, the BA534D 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 be flashing.
The value of the flashing digit may be changed by
pressing the
Up or Down buttons. When this digit
is correct pressing P will transfer control to the
next digit. When clip-off is set as required, press
the
E button to enter the revised figure and return
to the main programme menu.
If the flow rate falls below the entered threshold,
the rate display will show zero flow, totalisation will
stop and the HOLD annunciator will be activated.
The flow indicator will rotate for 2 seconds each
time an input pulse is received i.e. at input
frequencies above 0.5Hz it will appear to rotate
continuously.
Note: When the rate scale factor SCALE-r, the
timebase t-bASE, or the position of the rate
display decimal point are changed, clip-off will
automatically be reset to zero. If required, a new
clip-off threshold may then be entered.
5.13 Local reset of total display:
‘LOC. rSEt’
When activated this function enables the operator
to reset the BA534D total display to zero in the
display mode by operating the
Up and Down
push-buttons simultaneously for more than two
seconds. To check the status of the local reset
function select 'LOC.rSEt' from the menu and
press
P which will reveal if the function is 'On' or
'OFF'. If necessary press the Up or Down button
to change the setting, followed by the E button to
return to the main menu.
The total display may also be reset to zero
remotely by connecting terminals 7 and 8
together. See section 3.4 of this manual.