STX Signal Transmitter Installation and Operation ... - Kistler-Morse

Chapter 7. MVS-STX Calibration Menu
quantity of material in the vessel (usually
zero material, but it can be a known, nonzero
quantity). Zero_Cal is often entered at
some time after the initial installation and
calibration, when it is practical to empty the
vessel and refine the calibration.
Zero_Cal may be used to compensate for the
following circumstances:
• The estimated weight used when performing
a calibration by adding or subtracting
a known quantity of material is off by a
greater margin than can be tolerated.
• The vessel was not completely empty
at the start of a high-accuracy
calibration procedure.
Note
The Zero_Cal function cannot ‘repair’
a calibration in which the known
quantity added or subtracted was
actually incorrect, because the slope
of the line is not affected by setting
zero. If necessary, recalibrate.
Follow this procedure to refine the calibration
by setting zero:
1. If in Auto Mode (Auto LED illuminated),
press the Auto/Man Key to put the MVS
in Manual Mode. The Auto LED turns off.
2. Use the Arrow Keys to scroll to the
desired channel.
3. Press the Menu Key to display the Main
Menu. The display shows:
MAIN MENU
Disp I/O Cal
F1 F2 F3
4. Press the F3 Key to access the Cal
Menu. The display shows:
CALIBRATION MENU
Auto
5. Press the F1 Key to access the Auto
Menu. The display shows:
AUTO CAL MENU
LoSpan
Manual
F1 F2 F3
HiSpan
F1 F2 F3
6. Press the Menu Key to access the
menu’s second page. The display shows:
AUTO CAL MENU
Zero_Cal
Disply
7. Press the F1 Key to access Zero_Cal.
The display looks like this:
ZERO CALIBRATION
> 0 lbs
F1 F2 F3
(Units are consistent with Units Menu.)
8. Use the keypad or Arrow Keys to input a
value that represents the known quantity
of material (usually zero) in the vessel.
Press the Enter Key. The display acknowledges
the entry and returns to:
AUTO CAL MENU
Zero_Cal
Disply
F1 F2 F3
The MVS automatically makes all the
necessary corrections. However, the
entered values of Lo Span and Hi Span
weight remain in memory even though the
solid line of Figure 7-3 does not pass
through those two points. Those points
are used only to establish the slope of
the line.
9. Press the Esc Key to scroll up the menu
tree or press the Auto/Man Key to return
to channel monitoring.
Displaying Auto
Calibration Parameters
The second page of the Auto Cal Menu has a
display function. Disply allows you to view the
following calibration values, which have been
entered or internally calculated:
• Cnts/mV (digital counts per millivolt
of signal)
• 0mV cnts (digital counts corresponding
to 0 millivolts of signal)
• H_SPAN_W (entered hi span weight)
• L_SPAN_W (entered lo span weight)
• H_SPAN_C (hi span counts = digital
counts corresponding to hi span weight)
• L_SPAN_C (lo span counts = digital
counts corresponding to lo span weight)
• ZERO_WGT (entered zero calibration
weight if performed Zero_Cal;
otherwise, zero)
• ZERO_CNT (zero counts = digital counts
corresponding to zero calibration weight)
• SCF_WGT (scale factor weight
= hi span weight - lo span weight)
• SCF_CNT (scale factor counts
= hi span counts - lo span counts)
F1 F2 F3
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