Technical Reference Manual - InduSoft

Alarms, Events, and Trends
• Default Table Name:TRENDGGG ( GGG = Trend Worksheet Number; e.g., TREND001 for the Trend
Worksheet 001)
For more information about the structure of the database table that IWS uses to save history files, see
Database Interface.
Caution: You can specify String tags in many fields of the Trend worksheet, to change those
values during runtime, but doing so may affect how those values are saved in the trend history:
• When the history format is Proprietary, the value of the String tag is converted to a numerical
value (if possible) and then saved to the history file. If numeric conversion is not possible, then
a value of 0 is saved.
• When the history format is Database, the actual value of the String tag is saved in the
database.
• Database Configuration: Opens the Database Configuration dialog, where you can enter the requisite settings to
link the project to an external SQL Relational Database for the purpose of saving the trend history.
• Save On Trigger checkbox and field: Click (enable) and type a tag name to save trend samples when someone
changes the specified tag. (Tag change can be an event from the Scheduler.)
• Save On Tag Change checkbox: Click (enable) to always save the trend sample when a value change occurs in
any of the tags from that group.
• Advanced: Click to display the Trend Advanced Settings dialog. For information about completing the fields
in this window, see Batch History Configuration.
Use the Body parameters on this worksheet as follows:
• Tag Name field: Type the tag name to be saved in the history file.
• Dead Band field: Type a value to filter acceptable changes when Save on Tag Change is used. For example, Dead
Band has value = 5. If the tag value is 50 and changes to 52, the system will not register this variation in
the database, because it is less than 5. If the change is equal to or greater than 5, the new value will be
saved to the history file.
• Field field: Name of the field in the database where the tag will be stored. If this field is left blank, the name
of the tag will be used as the tag name. Array tags and classes will have the characters "[", "]" and "."
replaced by "_". Examples:
Tag Name
MyArray[1]
MyClass.Member1
MyClass[3].Member2
Default Field
MyArray_1
MyClass_Member1
MyClass_3_Member2
See also:
Note: The Trend task can accept only up to 240 tags in a single worksheet. If you manually
configure more than 240 tags in the same worksheet, then the Trend task will generate an error
when you run the finished project.
• Converting Trend History Files from Binary to Text
• Converting Trend History Files From Text to Binary
• Creating Batch History
• Configuring a Default Database for All Task History
Converting Trend History Files from Binary to Text
By default, IWS saves trend history files in a binary format (.hst). Because you may want to have these files
in .txt format, IWS provides the HST2TXT.EXE program to convert trend history files from binary into text
format.
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