NCR 7870 manual Verifying Calibration

Chapter 5: Calibration 5-11

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	Problem	Suspect Component
Code
1 - - - -	Calibration error	Scale Board
	A/D output below 000h at digital to	Load Cell
	analog converter
2 - - - -	Calibration error	Scale Board
	A/D output below 280h at digital to	Load Cell
	analog converter
3 - - - -	Calibration error	Scale Board
	Analog to digital converter output	Load Cell
	too high at 15 kg (30.0 lb.)
4 - - - -	Vibration to scale during calibration	Motors in checkstand
9 - - - -	Interference detected during	Top Plate is touching
	calibration	checkstand, scale was
		jarred, or overload screw
		is misadjusted.

If no error codes occur during calibration, four test procedures must be performed to verify calibration. These procedures are, in order,

•Increasing Load Test ,

•Over-Capacity Test,

•Decreasing Load Test, and

•Shift Test.