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Reference Manual Rev 3.23
Software Versions 3.xx
Page 42
8. Calibration
The calibration of the indicator is fully digital. The calibration results are stored in
permanent memory for use each time the instrument is powered up.
Note: Some of the digital setup steps can affect calibration. The BUILD and
OPTION settings MUST be configured before calibration is attempted.
To perform a calibration, when in Full Setup select the CAL Group using the <GRP> key.
The calibration programme will automatically prevent the instrument from being calibrated
into an application outside of its specification. If an attempt is made to calibrate outside of
the permitted range, an error message will display and the calibration will be abandoned.
Refer to Error Messages page 65.
The instrument has a wide-range A/D converter. The industrial calibration range of the
instrument extends well beyond the Trade approved range.
Note: It should not be assumed that just because the instrument has successfully
calibrated a scale, that the scale is correct for trade use. Always check the scale
build against the approval specification.
8.1. Performing a Digital Calibration with Test Weights
0
500
1000
1500
2000
2500
3000
3500
0
2
4
6
8
10
Load Cell Output (mV)
W
e
ight
(
K
g)
Span Point
(preferably at full load)
Zero Point
Figure 17: Chart - Zero and Span Points to Interpolate Weight from Load Cell
The Zero setting (CAL:ZERO) specifies a gross zero point for the scale. The Span
setting (CAL:SPAN) specifies a second point (preferably close to full scale) used
to convert the A/D readings into weighing units (eg. kg). Select either of the Zero
(CAL:ZERO) or Span (CAL:SPAN) calibration items. It is important that an initial
Zero calibration is performed before any SPAN calibrations. The chart shown here
demonstrates how the zero and span points are used to interpolate a weight reading
from the load cell reading.
Note: Calibration points (Zero, Span and Linearisation) must be spaced by at
least 2% of Full scale from each other.