NT21_Reference Manual (V069-E1-1) (986756), страница 51
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For this setting, a characterstring (title) can be registered to indicate the contents of the screen. Title isup to 24 characters in length.Only screens for which the History attribute is set are objects of the displayhistory record function.2. Initializing the Display HistoryBefore recording can be started, the display history must be initialized fromthe System Menu of the PT to clear the past records.3. Recording the Display HistoryOperate the PT as usual.When a screen for which the History attribute is set is displayed during operation, the time of display and number of times it has been displayed arerecorded.4. Checking the Display History RecordDisplay and check the recorded display history record.There are two methods for doing this: displaying the record from the SystemMenu, and displaying a screen with the display history record function during operation.In either case, the records can be presented in occurrence order (order ofdisplay) or frequency order (order of frequency of display).244Section 2-16Special FunctionsReference:S The History attribute can only be set for user screens.
It cannot be set for system screens and consequently these screens cannot be included in the display history record.S When an overlapping screen is displayed, the data for the parent screen is recorded.S Bit 11 (display history initialization) of the PT status control bits can also beused to initialize the display history record.Recording Format for theDisplay History RecordFor the display history record, the following data is recorded in the memory forscreens with the History attribute.• Screen number• Time of display• Display history titleReference: The display history record data is backed up by the battery in the PT and is therefore retained even when the power to the PT is turned OFF or the PT is reset.(The Battery is an option for the NT21.) If the Battery is not being used, the display history record data will be cleared when the power supply to the PT is turnedOFF or the PT is reset.Maximum Number of RecordsOccurrence OrderThe data of up to 1024 screens can be recorded in the occurrence order displayhistory record.
The operation when 1024 records is exceeded depends on thesetting made for Screen (Use Ring Buffer) on the PT Configuration – Systemscreen at the Support Tool: select whether the record is to be stopped or the older records are to be deleted.If no check mark is set for Screen (Use Ring Buffer), recording is stopped, and ifa check mark is set, the new data is recorded and the older data is deletedinstead.Frequency OrderThe data of up to 255 screens can be recorded in the frequency order displayhistory record.
Even if this limit is exceeded, still 255 records remain displayed.Checking the RecordThere are two methods for checking the display history record: checking the record contents in the Maintenance mode of the PT, and displaying a screen withthe display history record function during operation.Displayed ScreensIn either case of order of occurrence or order of frequency, the number of recordsthat can be displayed on one screen is 6 with the NT21 PTs, 14 withNT31/NT31C PTs, or 29 with NT631/NT631C PTs. To view those records thatare not displayed on the current screen, scroll the screen with the up and downtouch switch arrow keys.If no display history is recorded, the message Display history is not found.
is displayed.Order of OccurrenceThe screen records are displayed in the order the screens were displayed.Whether the records are displayed from the oldest first or from the newest first is245Section 2-16Special Functionsdetermined by memory switch setting at the PT. The following example showsan NT31/NT31C PT:Order of FrequencyThe screen records are displayed in the order of frequency of display (number oftimes displayed) of the corresponding screens.
The following example shows anNT31/NT31C PT:Checking the Record in the Maintenance ModeSelect the Maintenance mode from the System Menu and display the history record.For details on the System Menu operation, refer to section 6 of the Setup Manual.Checking the Record During OperationThe display history record can be checked during operation by displaying eitherof the following screens.Screen No. 9001: Occurrence history screenScreen No.
9002: Frequency history screenReference: Screen numbers 9001 and 9002 are reserved for displaying the display historyrecord. They cannot be used for other applications.2-16-2 Alarm History Record FunctionThe alarm history record function continually monitors the status of host bits setin advance, and records the times at which the statuses of these bits change to 1(ON). The setting for monitoring the bits can be made at the bit memory table.The recorded data can be displayed and checked even during operation, fromthe System Menu.Procedure for Using theAlarm History RecordFunction1, 2, 3...246The procedure for using the alarm history function is as follows:1.
Setting the Bit Memory TableAt the Support Tool, allocate host bits to a bit memory table entry and setHistory as the function of the bit memory table entry. At this time, it is pos-Special FunctionsSection 2-16sible to specify character string memory table entries that contain messagesindicating the contents of alarms.Only bits for which the History attribute is set are objects of the alarm historyrecord function. Bits for which History is set are continually monitored duringoperation of the PT regardless of the screen being displayed.2. Initializing the Alarm HistoryBefore recording can be started, the alarm history must be initialized fromthe System Menu of the PT to clear the past records.3.
Recording the Alarm HistoryOperate the PT as usual.When the status of a bit for which History is set changes to 1 during operation, the time of this event and the number of times the bit has come ON arerecorded.4. Checking the Alarm History RecordDisplay and check the recorded alarm history record.There are two methods for doing this: displaying the record from the SystemMenu, and displaying a screen for which an alarm history element is registered during operation.In either case, the records can be presented in occurrence order (order ofdisplay) or frequency order (order of frequency of display).Recording Format for theAlarm History RecordReference:For the alarm history record, the following data is recorded in the memory for bitmemory table entry for which the status of the allocated bits changes to 1 (ON).• Message (contents of a character string memory table entry set for the bitmemory table entry)• Time of displayS The alarm history record data is backed up by the battery in the PT and istherefore retained even when the power to the PT is turned OFF or the PT isreset.
(The Battery is an option for the NT21.) If the Battery is not being used,the alarm history record data will be cleared when the power supply to the PTis turned OFF or the PT is reset.S Bit 1 (alarm history initialization) of the PT status control bits can also be usedto initialize the alarm history.Maximum Number of RecordsChecking the Record• Occurrence orderThe data of up to 256 bit memory table entries (bits) can be recorded in theoccurrence order alarm history record. The operation when 256 records isexceeded depends on the setting made for Alarm (Use Ring Buffer) on thePT Configuration – System screen at the Support Tool: select whether therecord is to be stopped or the older records are to be deleted.If no check mark is set for Alarm (Use Ring Buffer), recording is stopped, andif a check mark is set, the old records are progressively deleted.• Frequency orderThe data of up to 255 screens/bit memory table entries can be recorded inthe frequency order alarm history record.
Even if this limit is exceeded, still255 records remain displayed.There are two methods for checking the alarm history record: checking the record contents in the Maintenance mode of the PT, and displaying a screen forwhich an alarm history element is registered during operation.The display for the alarm history record function differs depending on whether itwas called from the Maintenance mode or during operation.247Section 2-16Special FunctionsDisplayed DataThe data displayed with the alarm history record function are described below.Occurrence OrderThe records are displayed in the order in which the status of the set bit memorytable entries (bits) changed to 1 (ON). Whether the records are displayed fromthe oldest first or from the newest first is set with the memory switches at the PT.Frequency OrderThe records are displayed in the order of the number of times the statuses of thebit memory table entries have changed to 1 (ON).Checking the Record in the Maintenance ModeSelect the Maintenance mode from the System Menu and display the alarm history record.For details on the System Menu operation, refer to section 6 of the Setup Manual.When the record is checked in the Maintenance mode, screens like those shownbelow are displayed.
(The following examples show NT31/NT31C PTs.)Occurrence Order ScreenFrequency Order ScreenChecking the Record During OperationThe alarm history can be checked during operation by displaying a screen forwhich an alarm history element has been registered.In this case, the alarm history element is displayed in the manner shown below.However, note that the width and height of the alarm history element, and themethod of display for the time, can be changed by setting properties.
For details,refer to 2-11 Alarm List, Alarm History (page 182).Occurrence Order ScreenAbnormal remote I/O06/0616:02Abnormal high function unit06/0709:21Cycle time over06/1715:44Occurrence oftransmissionabnormalityCheck the remote I/Otransmission line!248Section 2-16Special FunctionsFrequency Order ScreenCycle time over114Abnormal high function unit153Abnormal remote I/O139Cycle time exceeds100 msec!The following countermeasure shouldbe taken:Program is checked again.Setting of cycle time over not detected(DM6655:X1XX)2-16-3 Resume FunctionThe PT has a function to protect the contents of memory table entries that havebeen changed during operation (by the numeral/character string setting function, or by an instruction from the host) and retain them even when the power tothe PT is OFF or the PT is reset, so that operation can be restarted in the samestatus the next time the PT is started.
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