4
LDB-ST1LE Batcher
Operating Mode
The Flow Computer can be thought of as making
a measurement of flow and then performing
calculations which are then updated periodically
on the display as rate and total. The pulse output,
analog output and the alarm relays are also
updated. The cycle then repeats itself.
Step 1: Update the measurements of input signals-
Raw Input Measurements are made at each
input.
Step 2 : Compute the Volumetric Flow-
Uncompensated ow is the term given to the ow in
volume units. The value is computed based on the
owmeter input type selected and augmented by
any performance enhancing linearization that has
been specied by the user.
Step 3: Check Flow Alarms-
The ow alarm functions have been assigned to
ow rate during the setup of the instrument. A
comparison is now made by comparing the current
ow rates against the specied hi and low limits.
Step 4: Compute the Flow Totals by Summation-
A ow total increment is computed for each ow
rate. This increment is computed by dividing the
pulses by the K-Factor and then summing. The
totalizer format also includes provisions for total
rollover.
Step 5: Total Preset Comparisons-
The total associated with a preset function is then
compared against the corresponding preset value
and any required control actions taken.
Step 6: Pulse Output Service-
The pulse output is next updated by scaling the total
increment which has just been determined by the
pulse output scaler and summing it to any residual
pulse output amount.
Step 7: Compute the Analog Output-
This designated ow rate value is now used to
compute the analog output.
Step 8: Update Display and Printer Output-
The instrument nally runs a task to update the
various table entries associated with the front panel
display and serial outputs.
Setup Mode
The setup mode is password protected by means
of a numeric lock out code established by the user.
In addition, a secret, manufacturers numeric unlock
entry sequence is available.
The system also provides a minimum implementation
of an “audit trail” which tracks signicant setup
changes to the unit. This feature is increasingly
being found of benet to users or simply required
by Weights and Measurement Ofcials in systems
used in commerce, trade, or “custody transfer”
applications.
A Worksheet is provided to assist the user in setting
up the instrument. An Easy Setup (EZ Setup)
feature is offered in the setup menu. The EZ Setup
routine is a quick and easy way to congure the unit
for the most commonly used instrument functions.
The setup mode has numerous subgrouping of
parameters needed for ow calculations. There is
a well conceived hierarchy to the setup parameter
list. Selections made at the beginning of the setup
affect offerings further down in the lists.
In the setup mode, the ow computer activates the
correct setup variables based on the instrument
conguration, the ow equation, and the hardware
selections, the ow transmitter type, and meter
enhancements (linearization) options selected. All
required setup parameters are enabled. All setup
parameters not required are suppressed.
A help line prompt is provided for each entry. In
addition a help message is available which may be
accessed by depressing the “HELP” key.
Also note that in the setup mode are parameter
selections which have preassigned industry
standard values. The unit will assume these values
unless they are modied by the user.
