
High Performance Oscilloscope Calibrator
Standard Calibration — Basic Sequences
95
'RESET CAL POINT'
Over a series of recalibration periods, a condition may be reached when the Calibration
memory for a particular Cal Point is heavily biased in one direction. A conflict can arise
between the limits on the O/P Amplitude value and the target value. In response to
successive attempts at adjustment, the 9500B will keep repeating the error message
'Outside amplitude range' and calibration is not accepted.
This conflict can often be resolved by pressing the 'RESET CAL POINT' soft key to clear
the cal memory to zero, then recalibrating.
If this does not work, then it could indicate one of two causes:
1.
The Model 9500B has developed a fault.
2.
The measuring instrument has developed a fault, is incorrectly set up, or is
incorrectly connected to the Model 9500B's terminals.
The cause should be determined and rectified before proceeding. If this is not possible,
then you should contact your Fluke Calibration Calibration Service Center.
Standard Calibration of AC Functions
Standard calibration of the Square Voltage and Sine Voltage functions in the 9500B uses
the same procedure as that described in sections, Introduction, Target Selection Screen —
Selecting Hardware Configurations, The Adjustment Screen and Calibrating the Model
9500B at Target Values of this section except that the frequency of the target calibration
points must also be set.
Output Frequency Synthesis
The frequency of the Model 9500B's Square Voltage and Sine Voltage output is derived
digitally from an internal reference frequency crystal, which is sufficiently stable for the
output frequencies of these functions not to require any routine calibration for at least
5 years (Refer to Special Cal: 'Adjust FREQ').
Changing the Output Frequency of Target Calibration Points
When you display target selection screens for AC functions on the Target Selection
screen, you will notice that the Saved Calibration Targets and Default Calibration Targets
all include a target calibration point frequency. As an example, the default calibration
targets for the Symmetrical Square Voltage, Cal Range 1 — Target 2 are illustrated in the
following screen:
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