Omron NT31 Operation Manuals page 411

Graphs
400
S Differences in trend graph display method according to percentage values
The display method of a trend graph differs according to the percentage value
range.
(1) When the percentage value is negative
The following happens, depending on the setting for "Display Sign":
- No check mark:
- Check mark:
(2) When the absolute value of the percentage value is in the range of 100% to
999%
If the percentage value enters the range 100 to 999% or −100 to −999%,
and the line projects out of the graph area, only the part of the line inside the
graph area is displayed.
If a check mark is set for "Display %", the calculated percentage value is
displayed.
(3) When the absolute value of the percentage value is greater than 1000%
If the percentage value exceeds 1000% or enters the range below −1000%
and the line projects out of the graph area, only the part of the line inside the
graph area is displayed, as in (2) above.
If a check mark is set for "Display %", the percentage value is displayed as
follows.
- "∗∗∗∗%"
S Data logging function and background function
The data logging function is a function for recording (logging) the displayed val-
ues internally.
Normally, the data sampled for a trend graph is not recorded internally, but by
using the data logging function it is possible to back track and display past data.
With the NT31/NT31C, the data logging function can be used for the data of up to
8 lines. The maximum data quantity that can be recorded for each is 1440
points, and when this limit is exceeded the data is deleted from the oldest points.
If the "Clear Log" touch switch has been set, the data can be cleared at any time.
The graph line is displayed as 0% ("Display %" is
shown in negative value).
Displayed in the minus range
100%
Latest data
0%
Latest data
−100%
Section 7-10
50%
−300%