Omron NT21 Reference Manual page 205

Alarm List, Alarm History
Reference: The number of characters in the specified date/time display are added to the
max. message length (1 to 40 characters) set in the general properties. For ex-
ample, if the max. message length is set to 40 characters and the Info Type is set
to Y/M/D h:m (15 digits), a total of 55 characters will be displayed in the alarm
history.
Message
Length
Display Result
The history is displayed as follows depending on the settings made for General
and Settings:
Message
(Number of digits complies
with Length)
For details on the method of display according to the General settings, refer to
Common Attributes (page 186).
Alarm histories allow the screen to be switched in accordance with bit memory
table entry settings. For details, refer to 2-3-3 Bit Memory Table (page 83).
Timing of Message Reading
For alarm lists and alarm histories in frequency order, when a message is dis-
played, scrolling, or screen switching, the character string memory table entry
set for the bit memory table entry is read, and the latest message is displayed.
In contrast, in the case of alarm histories in occurrence order, only when the sta-
tus of the allocated bit of the bit memory table entry changes to 1 (ON), the char-
acter string memory table entry set for the bit memory table entry is read and its
contents are recorded. Accordingly, even if the contents of the character string
memory table entry change later, the displayed message will be kept the re-
corded contents. However, if the status of another monitored host bit changes to
1 (ON) while an alarm history in occurrence order is being displayed, the latest
message at that point is displayed.
Display at Message Update
When the status of a monitored host bit changes during display of an alarm list/
alarm history, the display changes as follows:
With an Alarm List
With an alarm list, when the status of a monitored host bit changes to 1 (ON), the
corresponding message is displayed, and when it changes back to 0 (OFF), the
message is cleared (the messages are displayed in ascending order of bit
memory table entry numbers).
Maximum number of characters in the displayed message
NT31/NT31C: 1 to 39
NT631/NT631C: 1 to 40
For the alarm history function, the number of characters is
decreased by the number required to display the History
Info.
Restrictions also apply in accordance with the Scale
setting.
Frequency of occurrence/Time of occurrence
- Frequency:
- Year/month/day hour:minute:
- Month/day hour:minute:
- Hour:minute:
Line scroll touch switches
Page scroll touch switches
Section 2-11
4 digits
15 digits
12 digits
6 digits
189