Fluke 5500A, Service Manual

Page: 152 / 296

5500A
Service Manual
6-26
3. Set the DSO to these parameters:
•
Main Time Base position (initial):40 ns
•
Vertical scale: 200 mV/div, +900 mV offset
•
Trigger: source = ext; level = 0.5 V; ext atten = x10; slope = +;
mode = auto
•
Measurement Function: positive width
4. Press the GO ON blue softkey.
5. Adjust the DSO horizontal scale and main time base position until the pulse signal
spans between half and the full display. If no pulse is output, increase the pulse
width using the Calibrator Mainframe front panel knob until a pulse is output.
6. If prompted to adjust the pulse width by the Calibrator Mainframe display, adjust the
pulse width to as close to 4 ns as possible using the Calibrator Mainframe front panel
knob, then press the GO ON blue softkey.
7. Allow the DSO width reading to stabilize. Enter the reading via the Calibrator
Mainframe front panel keypad, then press ENTER.
Note
The Calibrator Mainframe issues a warning when the entered value is out
of bounds. If this warning occurs, recheck the setup and carefully re-enter
the reading with the proper multiplier (i.e., m, u, n, p). If the warning still
occurs, enter a value between the displayed pulse width and the
previously entered value. Keep attempting this, moving closer and closer
to the displayed pulse width, until the value is accepted. Complete the
pulse width calibration procedure. The pulse width calibration procedure
must now be repeated until all entered values are accepted the first time
without warning.
8. Repeat steps 5 to 7 until the Calibrator Mainframe display prompts to connect a
resistor. Press the OPTIONS, then STORE CONSTS blue softkeys to store the new
calibration constants.
6-42. MeasZ Calibration
The MeasZ function is calibrated using resistors and a capacitor of known values. The
actual resistance and capacitance values are entered while they are being measure by the
Calibrator Mainframe.
The resistors and capacitor must make a solid connection to a BNC(f) to enable a
connection to the end of the BNC cable supplied with the SC600. The resistance and
capacitance values must be known at this BNC(f) connector. Fluke uses an HP 3458A
DMM to make a 4-wire ohms measurement at the BNC(f) connector to determine the
actual resistance values and an HP 4192A Impedance Analyzer at 10 MHz to determine
the actual capacitance value.
This procedure uses the following equipment:
•
Resistors of known values: 1M
Ω
and 50
Ω
nominal
•
adapters to connect resistors to BNC(f) connector
•
adapters and capacitor to achieve 50 pF nominal value at the end of BNC(f)
connector
•
BNC cable supplied with the SC600
Refer to Figure 6-5 for setup connections.