Verifying Calibration - NCR 7870 User Manual

Verifying Calibration

This section describes how to verify that the 7870 has been properly
calibrated.
No error codes should appear during calibration. The codes are shown
in the table below. If a code is displayed, the calibration is invalid and
a corrective action must be undertaken before attempting recalibration.
Error
Code
1 - - - -
2 - - - -
3 - - - -
4 - - - -
9 - - - -
If no error codes occur during calibration, four test procedures must be
performed to verify calibration. These procedures are, in order,
Problem
Calibration error
A/D output below 000h at digital to
analog converter
Calibration error
A/D output below 280h at digital to
analog converter
Calibration error
Analog to digital converter output
too high at 15 kg (30.0 lb.)
Vibration to scale during calibration
Interference detected during
calibration
Increasing Load Test ,
Over-Capacity Test,
Decreasing Load Test, and
Shift Test.
Chapter 5: Calibration 5-11
Suspect Component
Scale Board
Load Cell
Scale Board
Load Cell
Scale Board
Load Cell
Motors in checkstand
Top Plate is touching
checkstand, scale was
jarred, or overload screw
is misadjusted.