Section 10: Calibrating the Model 9500B: Mainframe and Head Calibration 10.2-1
Final Width = 215mm
10.2 9500B Mainframe Calibration and Active Head™ Calibration
10.2.1 Introduction
The Model 9500B has been designed around a 1-year recalibration
interval. When they do need recalibration, it is not necessary to lose the
entire system while it is being performed.
In addition to being supported by traditional scope calibration standards,
the 9500B's mainframe and its Active Heads are calibrated separately.
The mainframe unit defines the DC and LF traceability, and is easily
calibrated on-site.
All high frequency calibrations (such as the leveled sinewave and pulse
outputs) are confined to the Active Heads, which can therefore be
calibrated independently. They are small enough and light enough to
be sent by regular mail services to a calibration laboratory. Our global
network of Service Centers provides a fast turnaround Active Head
recalibration service. By substituting a spare head for the one that is
being calibrated, the benefits of near-zero downtime become attainable.
10.2.2 Mainframe Unit Calibration
Mainframe Unit calibration correction factors are stored in non-volatile
calibration memory in the Mainframe Unit. The following calibrations
are available:
•'DC' voltage, positive and negative outputs, selected using the
WAVEFORM soft key on the DC/Square 'Target Selection' screen
when in Calibration mode;
•'Square' voltage waveforms, positive, negative and symmetrical
outputs, selected using the WAVEFORM soft key on the DC/
Square 'Target Selection' screen when in Calibration mode;
•'LF Sine' function, selected simply by pressing the front-panel
push-button when in Calibration mode;
•'Resistance Measurement', selected by pressing the Aux front-
panel push-button when in Calibration mode.
10.2.3 Active Head Calibration
Active Head calibration correction factors are stored in non-volatile
calibration memory in the Active Head itself. The following calibrations
are required:
•'Sine' flatness above 50kHz;
•'Low Edge' and 'Fast Edge' functions;
•'Load Capacitance' measurement functions;
•'Termination Compensation' functions.
Head calibration involves the use of a verified 9500B Mainframe.
Note: Heads can be calibrated only within the bandwidth of the
mainframe.
e.g. Head Model 9510 with Mainframe Variant 9500B/400
can only be calibrated to 400MHz.
10.2.4 Other Functions
Other 9500B functions are either derived directly from functions that
are calibrated, or are calibrated 'for life' during manufacture:
• Dual-Sine;
• Current;
• Composite Video;
• Linear Ramp;
• Overload Pulse;
• Zero Skew;
• Auxiliary Input;
• Input Leakage.
Attempting to select these functions during Mainframe calibration, (or
those in paras 10.2.3) while the Model 9500B is in CAL mode, will
result in an error message being displayed:
No calibration for this function
10.2.5 Mainframe Unit Manual Calibration
Mainframe Unit Calibration can be performed manually from the front
panel, and this is the main subject of this Section 10:
• Sub-section 10.3 covers general access to the processes via
Calibration Mode;
• Sub-section 10.4 deals with the general processes of selecting:
• Hardware configurations (Cal Ranges);
• Target Values within Cal Ranges;
• Modifying and saving modified Target Values for individual
calibration environments;
• Adjusting the 9500B output values to calibrate Cal Ranges
(thereby storing correction factors in non-volatile Calibration
Memory).
• Sub-section 10.5 details front panel operation to calibrate functions,
providing connection diagrams and sequenced procedures.
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