Fluke 5790A, Operator'S Manual

Page: 63 / 220

Front Panel Operation
Instructions for Measurement Mode
4
4-15
tracks the source instrument and appears to oscillate between ranges. The 5790A should
be range locked to the desired range and then the voltage applied from either 5205A or
5215A. This will prevent a cyclic auto-range condition between the 5790A, 5205A, and
5215A instruments. When a 5205A is used as the boost amplifier for the 5700A, a slew
rate trip condition is avoided because the 5700A forces a controlled ramp to the final
voltage. Auto-ranging will then work as expected on the 5790A.
4-21. Selecting Continuous or External (Single) Trigger
When the 5790A is in continuous trigger mode, the instrument is continuously taking
measurements. This is the initial setting at each power-up. As soon as one measurement
is completed, the 5790A begins a new measurement at the active input. Select continuous
trigger mode by pressing [EX TRIG] so that the keycap indicator is off.
In the external trigger mode, the 5790A only takes a measurement when you press
[TRIG]. When you press [TRIG], the 5790A begins a new measurement, even if a
partially completed measurement is under way. Select external trigger mode by pressing
[EX TRIG] so that its keycap indicator is lit.
When the Digital Filter is active and the 5790A is in external trigger mode, pressing
[TRIG] begins a series of measurements. When the filter is full, the "U" annunciator goes
out and the 5790A stops sampling the input until you press [TRIG] again or change to
autotrigger mode.
4-22. Instructions for Measurement Mode
In measurement mode, the 5790A measures a voltage applied to the selected input. To
take a measurement, simply select an input by pressing one of the input keys so that the
associated keycap indicator lights. Depending on trigger mode, the instrument takes
single readings when you press [TRIG] or it takes continuous readings. Refer to
"Operating Instructions for All Modes" for other settable operating parameters and
information about overrange and underrange displays.
Two examples of measurement mode applications are determining the error of an ac
source and determining the error of an ac voltmeter. No external calibrators or standards
are required during measurement mode operations unless you are calibrating a voltmeter.
you are taking a measurement the displays appears as follows (assuming HI RES is ON
or Digital Filter is MEDIUM or SLOW):
+
kHz
add13f.eps
add08fe.eps