HP HP 8753E, Руководство пользователя, Страница: 396 / 699

Limits are checked only at the actual measured data points. It is possible for a device to be out
of specification without a limit test failure indication if the point density is insufficient. Be sure
to specify a high enough number of measurement points in the stimulus menu.
Limit lines are displayed only on Cartesian formats. In polar and Smith chart formats, limit
testing of one value is available: the value tested depends on the marker mode and is the
magnitude or the value in a complex pair. The message
NO LIMIT LINES DISPLAYED
is
shown on the display in polar and Smith chart formats.
The list values feature in the copy menu provides tabular listings to the display or a printer
for every measured stimulus value. These include limit line or limit test information if these
functions are activated. If limit testing is on, an asterisk is listed next to any measured value
that is out of limits. If limit lines are on, and other listed data sufficient space, the upper
limit and lower limit are listed, together with the margin by which the device data passes or
fails the nearest limit.
If limit lines are on, they are plotted with the data on a plot. If limit testing is on, the PASS or
FAIL
message is plotted, and the failing portions of the trace that are a different color on the
display are also a different color on the plot. If limits are specified, they are saved in memory
with an instrument state.
Edit Limits Menu
This menu allows you to specify limits for limit lines or limit testing, and presents a table of
limit values on the display. Limits are defined in segments Each segment is a portion of the
stimulus span. Up to 22 limit segments can be specified for each channel. The limit segments
do not have to be entered in any particular order: the analyzer automatically sorts them and
lists them on the display in increasing order of start stimulus value.
For each segment, the table lists the segment number, the starting stimulus value, upper limit,
lower limit, and limit type. The ending stimulus value is the start value of the next segment,
or a segment can be terminated with a single point segment. You can enter limit values as
upper and lower limits or delta limits and middle value. As new limit segments are defined, the
tabular listing is updated. If limit lines are switched on, they are shown on the display.
If no limits have been defined, the table of limit values shows the
Limit
segments are added to the table using the or edited with the as
. .
previously described. The last segment on the list is followed by the notation END.
Edit Segment Menu
This menu sets the values of the individual limit segments The segment to
be modified,
or a
default segment, is selected in the edit limits menu. The stimulus value can be set with the
controls in the entry block or with a marker (the marker is activated automatically when this
menu is presented). The limit values can be as upper and lower limits, or delta limits
and middle value. Both an upper limit and a lower limit (or delta limits) must be defined:
if only one limit is required for a particular measurement, force the other out of range (for
example or -500
As new values are entered, the tabular listing of limit values is updated.
Segments do not have to be listed in any particular order: the analyzer sorts them
menu is pressed. However, the easiest way to enter a set of limits is to start with the lowest
stimulus value and define the segments from left to right of the display, with limit lines turned
on as a visual check.
Application and Operation Concepts 16