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2-3
Section
Memory Tables
80
Reference:
The alarm history can also be checked by pressing the Alarm History touch
switch on the MAINTENANCE MODE MENU screen of the PT. For details, refer
to section 6 of the
Setup Manual.
When a bit memory table is allocated to a bit at the host, the contents of the bit
are read and processing in accordance with the bit status is executed.
However, reading is only executed in the following case.
When a function (screen changeover, alarm history) is set for the bit memory
table.
Bit memory tables have no output function. The contents of bit memory tables
are not written to bits at the host.
Bit memory tables have no data processing function.
Relationship with Other Elements
•
When the alarm list function is used, messages and image/library data can be
displayed in real time in accordance with the status of bits at the host (page
173).
•
When the alarm history function is used, the time when the status of the host bit
changes to 1 (ON), and the number of times it comes ON, can be displayed
(page 173).
Reference:
When the alarm history record area has become full, processing is carried out in
accordance with the settings made for History Setting under Tools – PT Configu-
ration – System at the Support Tool.
S
Alarm (Use Ring Buffer)
If a check mark is set here, when an alarm occurs after the record area become
full, the oldest record data is deleted in order to allow the new alarm history data
to be stored (alarm pushup storage).
If no check mark is set, no more new alarm history data is stored after the re-
cord area becomes full.
S
Screen (Use Ring Buffer)
If a check mark is set here, when a screen for which the history property is set
after the record area has become full, the oldest record data is deleted and new
display history data is stored (alarm pushup storage).
If no check mark is set here, when the record area becomes full, no more new
display history data is stored.
Input Functions
Output Functions
Processing Functions
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Summary of Contents for NT21 Series
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