Great Plains Industries 03 Guía De Operaciónes página 2

To determine the exact volume measured
with each use, use the Batch Total. To zero
the Batch Total, make sure the meter is on
and hold down the DISPLAY button for
three seconds until zeros appear. If
LOCKED ("LOCKED") appears on the read-
out, the Cumulative Total is displayed. It
cannot be manually zeroed. Press and re-
lease DISPLAY until LOCKED does not ap-
pear. If the numbers in the readout are dim
or fading, the batteries need replaced. See
details in the Maintenance Section.
INSTALLATION
The following suggestions help maximize
performance. The meter can be mounted
either vertically or horizontally. It should be
field calibrated in the same orientation in
which it is mounted. Avoid installing the
meter in electrically "noisy" environments.
If installed within15 cm of large motors, re-
lays or transformers, the meter's accuracy
may be adversely affected.
For Low Flow or One Inch Meters, install
with 51 cm of straight pipe upstream and
13 cm of straight pipe downstream. For Two
Inch Meters, install with 102 cm of straight
pipe upstream and 26 cm of straight pipe
downstream.
Flow control valves upstream from the
meter and within the straight pipe distances
given above can adversely effect meter
accuracy. This is especially true when mea-
suring liquids with low vapor pressures. If
cavitation effects meter accuracy, a flow
control valve on the downstream side of the
meter can provide a back pressure of 0.3
to 3.4 bar (5 to 50 PSI) to minimize the prob-
lem.
Foreign material in liquid can clog the
meter's rotor. If the problem effects meter
accuracy or material coats the rotor, install
screens to filter the incoming flow. For Low
Flow meters use a 25 micron or microme-
ter screen. For One Inch or Two Inch Meters
use a 500 micron or micrometer screen. For
maximum accuracy, the velocity profile of
the flow entering the meter must be uniform
throughout the cross section of the pipe.
2
OPERATIONS
All operations are reflected in the readout
on the meter's face. (Figure 4) The top line
identifies the calibration curve. The middle
line reflects flow information. The bottom
line shows information from the totalizer.
The Batch Total indicates totalization flow
during a single use. It is shown as TOTAL
("TOTAL") followed by a number on the bot-
tom line. On most models this is TOTAL 2
("TOTAL 2"). To zero the Batch Total, make
sure the Batch Total is displayed and hold
DISPLAY ("DISPLAY") down until the read-
out changes to zeros.
The Cumulative Total is the total of all liq-
uid measured since the meter's power sup-
ply was connected. This total is labeled with
TOTAL 1 and always LOCKED ("LOCKED"),
because it cannot be manually zeroed (Fig-
ure 3). To change between totals, press and
release DISPLAY. Generally, the readout
changes when the buttons are released.
The Cumulative Total returns to zero when
batteries are removed or lose power or
when the total reaches its maximum value
of 999,999.
The two types of calibration curves, Field
Calibration and Factory Calibration, are
shown on the top line of the readout. A Field
Calibration Curve is set by the user. It can
be changed or modified at any time using
procedures given in the Calibration Section
below. A Factory Calibration Curve is pre-
set by the manufacturer and stored perma-
nently in the meter's computer. Factory
Calibration Curves display PRESET ("PRE-
SET") on the top line (Figure 4).
To change Calibration Curves, hold the CALI-
BRATE button ("CALIBRATE") down while
pressing and releasing DISPLAY ("DIS-
PLAY"). When the desired curve appears,
release both buttons. Field Calibration is
labeled with CAL ("CAL") followed by a let-
ter. On most models this is CAL B ("CAL B").
All units will be configured with a "factory"
calibration curve. Both gallons and litres are
available ("GAL" or "LTR" will be displayed).
Use the CALIBRATE and DISPLAY buttons
to switch between gallons and litres. This
curve is NOT user adjustable: the word
"PRESET" is displayed to show this (Fig-
ure 4). The factory calibrations is stored
permanetly in the computer's memory.