Omron NT21 User Manual

2-11SectionAlarm List, Alarm History
183
Differences Between Alarm List and Alarm History
The alarm list and alarm history differ in the following respects.
Item Alarm List Alarm History
Display
method
As element only As element, and as a screen displayed from the
System Menu
Monitored
data
Host bits allocated
to bit memory table
entry within the
designated range
Host bits allocated to bit memory table entries for
which History is set.
Monitor
timing
While the alarm list
element is dis-
played only
Continuous monitoring regardless of the dis-
played screen
Recording No recording
executed
Time of occurrence is recorded.
Message
contents
When a message
is displayed for an
alarm list, the con-
tents of the char-
acter string
memory table
entry set for the bit
memory table
entry are read.
- Occurrence order:
When the status of a monitored bit at the host
changes to 1 (ON), the contents of the charac-
ter string memory table entry set for the bit
memory table entry are read.
- Frequency order:
When a message is displayed for an alarm his-
tory, the contents of the character string
memory table entry set for the bit memory table
entry are read.
Output
data to
the Sup-
port Tool
Not possible for
there is no record
data
Possible (occurrence order and frequency order
records transmitted simultaneously)
Display
order
Ascending order of
bit memory table
entry numbers
Select either of the following:
- Occurrence order:
Chronological order in which the statuses of the
monitored bits changed to 1 (ON) (displayed
from the oldest record first or the newest record
first depending on the memory switch setting at
the PT)
- Frequency order:
Order based on the number of times the status
of each bit has changed to 1 (ON), from most to
least frequent.

Omron NT21 Specifications

General

Brand	Omron
Model	NT21
Category	Touch terminals
Language	English