Fluke PM6690 - Limit Mode; Limits and Graphics

Limit Mode
The Limit Mode offers three choices:
•
Above
Results above the set lower limit will
pass. A flashing
LIM symbol on the dis
-
play reports that the measurement re
-
sult has been below the lower limit at
least once since the measurement
started. Use
RESTART to reset the
LIM symbol to its non-flashing state.
•
Below
Results below the set upper limit will
pass. A flashing
LIM symbol on the dis
-
play reports that the measurement re
-
sult has been above the upper limit at
least once since the measurement
started. Use
RESTART to reset the
LIM symbol to its non-flashing state.
•
Range
Results inside the set limits will pass. A
flashing
LIM symbol on the display re-
ports that the measurement result has
been below the lower limit or above the
upper limit at least once since the mea-
surement started. Use
RESTART to
reset the
LIM symbol to its non-flashing
state.
If Range is selected and the presentation
mode is VALUES, a one-dimensional graphic
representation of the current measurement
value in relation to the limits can be seen at
the same time as the numerical value.
The upper limit (UL) and the lower limit (LL)
are vertical bars below the main numerical
display, and their numerical values are dis
-
played in small digits adjacent to the bars. See
Fig. 6-3.
This type of graphic resembles a classic ana
-
log pointer instrument, where the pointer is a
"happy smiley" as long as it is positioned
inside the limits and a "sad smiley" when it
gets outside the limits but is still within the
display area. Values that fall outside the dis
-
play area are represented by a "<"attheleft
edge or a ">" at the right edge.
The location of the bars is fixed, so the "in
-
side" range takes up the mid third of the dis
-
play area. This means that the resolution and
the scale length are set by the limits that have
been entered by the operator.
Limits and
Graphics
Limits can also be applied to the two-dimen-
sional graphics, the trend plot and the histo-
gram. By introducing limits you can inhibit
the auto-scaling and indirectly set the scale
length and the resolution.
Limits and Graphics 6-7
Process
Fig. 6-3 The analog limit monitor.
Fig. 6-4 Limits in a trend plot.
Fig. 6-5 Limits in a histogram.