Tektronix Keithley 2268 Series, Справочное руководство

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Calibration and Troubleshooting Series 2268 850 Watt DC Power Supplies Reference Manual
194 2268S-901-01 Rev. A / January 2015
MAIN VOLTAGE AND CURRENT CALIBRATION PRINCIPLE
Understanding the Problem
Figure 85 illustrates two sources of analog programming error: gain error and offset error.
Gain error is the departure from the ideal slope of the measured versus programmed line.
Offset error is the magnitude of the measured value when the programmed value is zero.
Calibrating one will affect the other so an iterative calibration procedure is used.
For best results, iterative calibration of gain and offset will be required. After first calibration
of both, repeat gain calibration for 90% of maximum value and offset calibration for 10% of
maximum value. Repeat as necessary.
Figure 85: Offset (Intercept) Error and Gain (Slope) Error
M
eas
ur
ed
V
al
ue
Programmed Value
Gain Error
Offset Error