Making Measurements; Error - HP 54501A Programming Reference Manual

Measurement
Error
If
a
measurement cannot
be made,
typically
because the proper portion
of
the
waveform
is
not displayed, the value returned for that parameter
is
+ 9.99999E
+
37.
This is an
error
value that
is
output when
a
measurement
cannot be made.
Making
Measurements
If
more
than one waveform, edge,
or pulse is displayed, time
measurements are
made
on the first
(left-most) portion of the displayed
waveform that
can
be
used.
When
any
of the defined measurements are
requested,
the oscilloscope first
determines the top
(100%)
and base
(0%)
voltages of the
waveform.
From
this information, it can determine the other important voltage
values
(10%
voltage,
90% voltage, and
50% voltage) for making the
measurements.
The 10%
and
90%
voltage values are used in the risetime
and falltime measurements when standard measurements are
selected.
The 50%
voltage value is
used for measuring frequency, period, pulse
width, and
duty cycle with standard
measurements selected..
The measurements can
also
be made using
user
defined parameters
instead
of the standard measurement values.
When
the command form of the front-panel measurements, preshoot, or
overshoot
is
used
the instrument
is
placed into the continuous
measurement mode. When the query form of
these measurements
is
used
continuous measurement mode
is
turned off, the measurement
is
made
one time and the measurement
result
is
returned.
Voltage
measurements are made using the entire display. Therefore, if
you want
to make
a
measurement on
a
particular
cycle,
display only that
cycle on the display.
Measure Subsystem
14-2
HP 54501A
Programming