14
5.10 Resetting grand total: CLr. Gtot
The grand total is a separate sixteen digit
counter which duplicates the total display but is
not zeroed when the total display is reset to
zero. The grand total may be viewed in the
display mode in two eight digit sections as
described in section 2.1 of this manual.
The grand total counter can only be reset to
zero from the 'CLr. Gtot' function in the main
programme menu. To zero the grand total
counter select 'CLr. Gtot' and press
P
which will
cause the instrument to display 'Clr. no' with 'no'
flashing. Continuously press the
Up
or
Down
push-buttons until 'CLr. YES' is displayed and
then press
P
which will result in a '0000' prompt.
Using the
Up
and
Down
buttons and the
P
button to move to the next digit, confirm the
request by entering the password 'SurE'. Note
'S' is entered as '5'. Pressing
E
will then reset
the grand total counter to zero and return the
instrument to the 'CLr. Gtot' prompt in the main
menu.
CAUTION
After resetting the grand total
counter to zero the old grand
total can not be recovered.
5.11 Timebase: t-bASE
Together with the total scale factor 'SCALE-t',
this function defines the arithmetic relationship
between the rate and total displays. To
calculate total flow the timebase divides the rate
display by 1, 60 or 3,600 depending upon
whether the BA554D rate display represents
flow per second, per minute or per hour. See
Fig 6.
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 though the following
three options.
BA554D
Rate display
represents
Flow
Select
In
t-bASE
menu
Total display
= rate display
divided by
Per second
tb – 1
1
Per minute
tb – 60
60
Per hour
tb – 3600
3600
Select the required divisor and press
E
to return
to the main menu.
5.12 Function of the
P
push-button: C - - P
This parameter defines the function of the
P
push-button when the BA554D is in the
operating mode. While the
P
button is pushed
the instrument will display the input current in
milliamps or as a percentage of the span.
To check or change the parameter select 'C - -P'
from the main menu and press
P
to reveal the
current setting. Pressing the
Up
or
Down
button
will toggle the instrument between the two
options '4-20' and 'PC', the input current in
milliamps and the input as a percentage of span.
When the required option is displayed press
E
to
store the selection and return to the main menu.
Accuracy depends upon the accuracy of the
internal references which should be periodically
calibrated - see section 5.9.2
5.13 Total scale factor: SCALE-t
Together with the timebase 't-bASE', this is a
dividing factor which defines the arithmetic
relationship between the rate and total displays.
The total scale factor may be set to any value
between 0.0001 and 65535* allowing the total
flow and rate of flow to be displayed in different
engineering units.
SCALE-t = Units of rate display
Units of total display
When calculating SCALE-t the required units of
measurement for the total display must be
converted to those used for the rate display as
shown in following example:
The BA554D rate display represents litres per
second but the total flow display is required in
UK gallons. There are 4.5461 litres in a UK
gallon.
SCALE-t = Units of rate display
Units of total display
= 1 litre = 1 litre
1 gallon 1/(4.5461) litres
SCALE-t = 4.5461
Alternatively if the total display is required in
thousand of UK gallons
= 1 litre = 1 litre
1 gallon 1/(4546.1) litres
SCALE-t = 4546.1
