Technical Reference Manual - InduSoft

Alarms, Events, and Trends
Tip: You can enter tag names between curly brackets in this field (e.g., {MyTag})
• Save data even if batch is not running: If this field is unchecked, the historical data will be saved only when the
tag in the Start/Stop field is TRUE.
Tip: The Batch Historical data can be displayed to the user in either Graphical or Table format.
See Trend Folder or Grid Object to display information in these formats.
In the Disk Space Control area, you can control disk usage:
• History Life Time (days) field: Specify how many days to keep the history file on the disk. After the specified
period, IWS automatically erases the file. Use this option only for files based on a date.
• Compress After (days) field: Specify how many days to keep the trend history file ( *.hst ) on the disk before
compressing the file. After the specified period, IWS automatically compresses the file. Use this option only
for files based on a date. This option is not available for Windows Embedded target systems.
In the Bad Quality area, you can determine what value will actually be saved in the batch history when the tag
quality is BAD:
Type
Tag Value
Min Value
Max Value
Value
NaN
Description
The actual value of the project tag when the tag quality was BAD, plus the specified Offset (if any).
The minimum historical value of the project tag, minus the specified Offset (if any).
The maximum historical value of the project tag, plus the specified Offset (if any).
The specified Value only.
Not a number.
Please note that when History Format is Database and Bad Quality is NaN, all of the database fields will be saved as Float type.
Also, if a Trend Control screen object is configured to use the history generated by this Trend worksheet, then NaN entries are counted
as 0 for the purpose of calculating a trend's statistical average and deviation.
Note: The Bad Quality feature cannot be used in projects running on Windows Embedded target
systems.
Finally, in the Disable All Data Saving box, type the name of a project tag. When the value of the tag is TRUE (nonzero)
during runtime, all data saving is disabled for this worksheet. Other Trend worksheets are not affected.
Setting the Trend Database
1. Click the Tasks tab, and right-click the Trend folder. Double-click the applicable Trend.
2. Click the arrow to the right of the History Format field. Select Database.
3. Click the Database Configuration button. This opens the Database Configuration dialog. Enter the applicable
data in this window. Click OK when you are finished.
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