C&C Mode
C&C Mode Setup Categories
46
Manual Calibration
Figure 44 illustrates meter Manual Calibration (multipoint) setup procedure. This method requires the meter
manufacturer’s meter error chart.
Figure 44. Meter Manual Calibration Setup
Press ENTER
to accept the
entry.
Press ENTER
to accept the
entry.
MANUAL CALIBRATE
SET FLOW RATE
Press up/down arrows
to scroll through the
numbers, and NEXT
to move from one
digit to the next.
SET COUNTS
Press up/down arrows
to scroll through the
numbers, and NEXT
to move from one
digit to the next.
CALB RATE 1
CALB RATE 8
+
-
+
FLOW RATE
ENCODER COUNTS
+
-
+
In the MANUAL CALIBRATE option you use a
combination of the vehicle meter's Flow Rate Error
chart and one flow rate/encoder pair determined in the
Auto Calibrate procedure (Figure 42 on previous
page).
For example, you want to manually calibrate the meter
on Truck 101 that will operate in a 60 to 700 gallons/
minute range. You want to enter 3 calibration rates for
the vehicle's meter at 60, 340 (approximate midpoint
flow rate), and 700 gpm flow rates. With the meter's
error chart you can run the Auto Calibrate (see Figure
42 on previous page) for one of these rates and
interpolate the other two from the chart.
Perform the Auto Calibrate procedure dispensing at a
340 gpm flow rate:
Result: 19.973 counts per gallon
On the meter's error chart, find the meter's %error for the
60, 340, and 700 gpm flow rates:
Use the meter error table to calculate the Calibration
Rate for the other two flow rates.
700 gpm: 19.973 x [1 + (-0.0080)} = 19.957 counts
60 gpm: 19.973 x [1 +(+0.00110)] = 19.995 counts
Using the Manual Calibration method, the
difference in adjacent encoder counts must be
less than 0.25%, and in the Truck 101 graph at
left, you can see that the difference between
any adjacent counts of the 3 calibration flow
rates (in red) is less than 0.25%. Even the
difference between the low (19.998) and high
(19.957) counts is less than 0.25%!
The operator could use just the low and high
rate/count pairs alone. However, using the low,
mid-point, and high flow rate/encoder count
pairs would be a better choice.
In this example, the operator would enter the
following flow rate/encoder count pairs:
60/19.995, 340/19.973,and 700/19.957.
Again referring to the example at left, had the
difference between any of the two counts been
greater than 0.25%, the operator would have had
to use a lower flow rate for the next calibration
point. Instead of 3 points, all 8 might be
necessary, and perhaps closer together.
For installations (such as a terminal) in which only
one flow rate is used, the operator can calculate
the encoder count at the desired flow rate and
enter only one calibration rate using that flow
rate/encoder count pair.
Note that each Calibration Rate's current
Flow Rate will appear in the Register
Field and its current Encoder Count will
appear in the Preset Field.
Enter the desired flow
rate for this calibration
rate.
Enter the calculated
Encoder Count
for this calibration rate.
Repeat this procedure until
you have entered a corrected
encoder count from the table
for each of your flow rates.
20.00
19.99
19.98
19.97
19.96
19.95
0
240
480
720
19.995
19.973
19.957
Encoder Counts
Flow Rates for Jet Fuel (gal/min)
MANUAL CALIBRATION EXAMPLE - TRUCK 101
60
340
700
Flow Rate
(gpm)
60
340
700
Error
(%)
+0.190
+0.080
+0.000
Meter Error Chart
RETURN TO
PROD CAL 1
(FIGURE 41)
