Fluke 5500A, Руководство по обслуживанию

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5500A
Service Manual
6-18
The Calibrator Mainframe must complete a warm-up period and the SC600 must be
enabled for at least 5 minutes prior to calibration to allow internal components to
thermally stabilize. The Calibrator Mainframe warm-up period is at least twice the
length of time the calibrator was powered off, up to a maximum of 30 minutes. The
SC600 is enabled by pressing the front panel SCOPE key. The green indicator on the
SCOPE key will be illuminated when the SC600 is enabled.
Much of the SC600 can be calibrated interactively from the front panel. Enable the
SC600 and wait at least 5 minutes. Enter Scope Cal mode by pressing the front panel
SETUP key, CAL blue softkey, second CAL blue softkey, and SCOPE CAL blue
softkey. Entering Scope Cal mode prior to having the SC600 enabled for at least 5
minutes will cause a warning message to be displayed.
All equipment specified for SC600 calibration must be calibrated, certified traceable if
traceability is to be maintained, and operating within their normal specified operating
environment. It is also important to ensure that the equipment has had sufficient time to
warm up prior to its use. Refer to each equipment’s operating manual for details.
Before you begin calibration, you may wish to review all of the procedures in advance to
ensure you have the resources to complete them.
The Calibrator Mainframe first prompts the user to calibrate the DC Voltage function. If
another function is to be calibrated, alternately press the OPTIONS and NEXT
SECTION blue softkeys until the desired function is reached.
6-29. Calibration and Verification of Square Wave Voltage
Functions
The Voltage, Edge, and Wave Generator functions have square wave voltages that need
to be calibrated or verified. The HP3458A digital multimeter can be programmed from
either the front panel or over the remote interface to make these measurements.
6-30. Overview of HP3458A Operation
The Hewlett-Packard 3458A digital multimeter is setup as a digitizer to measure the
peak-to-peak value of the signal. It is set to DCV, using various analog-to-digital
integration times and triggering commands to measure the topline and baseline of the
square wave signal.
6-31. Setup for SC600 Voltage Square Wave Measurements
By controlling the HP 3458A’s integration and sample time, it can be used to make
accurate, repeatable measurements of both the topline and baseline of the Voltage
Square Wave up to 10 kHz. To make these measurements, the HP 3458A’s External
Trigger function is used in conjunction with the SC600’s External Trigger output. In
general, the HP 3458A is setup to make an analog-to-digital conversion after receiving
the falling edge of an external trigger. The conversion does not take place until a time
determined by the 3458A “DELAY” command. The actual integration time is set
according to the frequency that the DMM is measuring. Table 6-16 below summarizes
the DMM settings required to make topline and baseline measurements. Figure 6-2
illustrates the proper connections for this setup.