Kistler-Morse Weigh II, Installation And Operation Manual

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6-2
Chapter 6. Calibration
High-Accuracy Calibration
The high-accuracy calibration procedure
provides the highest accuracy, but requires
that the vessel be completely empty to start.
The principle behind the calibration follows.
The vessel is completely emptied, and the Lo
Span is set to zero [point (1) in Figure 6-2]. A
known quantity of material, representing at
least 25% of the vessel’s total capacity, is
then added to the vessel. That quantity is
entered as the
Hi Span value [point (2) in
Figure 6-2]. The Weigh II saves in memory
the Lo and Hi Span weights as well as the
digital counts associated with each weight.
These values define the straight line shown in
Figure 6-2. The slope of the line is called the
Scale Factor, which is calculated internally.
The accuracy of the calibration improves the
greater the known quantity of material added
during the calibration procedure. For ex-
ample, adding 50% of the vessel’s total
capacity results in greater accuracy than
adding 25% of the total capacity.
Follow this procedure to perform a high-
accuracy calibration.
1. Completely empty the vessel.
2. If the Weigh II is in Auto Mode (Auto LED
illuminated), press the Auto/Man Key to
put the system in Manual Mode. The Auto
LED turns off.
3. Use the Up Arrow or Down Arrow Key to
scroll to the desired vessel .
4. Press the Menu Key to display the Main
Menu. The display shows:
5. Press the F3 Key to access the Cal Menu.
The display shows:
6. Press the F1 Key to access the Auto
Menu. The display shows:
7. Press the F1 Key to access LoSpan . The
display looks like this:
The unit of measure you set up in the
Units Menu shows in place of lbs.
8. Use the keypad or the Up and Down Arrow
Keys to input zero as the Lo Span value.
Press the Enter Key to save the value in
memory.
Lo Span is now set [point (1) in
Figure 6-2]. The display flashes a mes-
sage acknowledging your entry and returns
to:
Figure 6-2. High-Accuracy Calibration
WII MAIN MENU
Disp I/O Cal
F1 F2 F3
CALIBRATION MENU
Auto Manual
F1 F2 F3
LO SPAN AUTO CAL
> X lbs
F1 F2 F3
AUTO CAL MENU
LoSpan HiSpan
F1 F2 F3
AUTO CAL MENU
LoSpan HiSpan
F1 F2 F3
Indicated
Weight
Hi Span
Weight
Weight
Signal
in Counts
Lo Span
Weight
(Zero)
Added
Known
Quantity
(1)
(2)
Scale Factor Wt = Hi Span Wt - Lo Span Wt
Scale Factor Cnts = Hi Span Cnts - Lo Span Cnts
Slope =
Scale Factor Weight
Scale Factor Counts
Lo Span
Counts Hi Span
Counts