Web Port trend management is based on trend functionality being enabled on tags.
It is the list of trend suffixes in symbol librarys (see chapter "Symbol library") as well as trend settings on each tag that indicate when a tag is being trended.
If the tag meets the requirement, it is trended according to default settings (see chapter "Trend settings") unless otherwise stated in the tag's trend settings that have priority.
Web Port Trend function is disabled by default.
When trend is activated Web Port will by default save trend data indefinitely. As a calculation example, 500 trend tags saved every 10 minutes will require ~800 MB disk space per year. To limit how long trend data is saved, see chapter "Database Settings".
Web Port trend settings are mainly made in SYSTEM SETTINGS/TREND (see chapter Trend settings->General settings). Trend settings for tags are made in the tag list (see chapter "Tag settings->Trend options").
Basic trend settings are accessed via SYSTEM SETTINGS/TREND/BASIC SETTINGS.
The following settings can be made:
|Enable trend support(checkbox)||Enables trend logging|
|Trend Interval||Indicates how often logging is done unless otherwise stated for trend
tags. Smallest valid value is 0.1 (100ms).
NOTE! A short trend interval will require a lot more disk space.
See calculated disk required under System settings/Server/Database settings
|Trend type||Indicates whether logging should be done periodically or with changes|
|Scaling of Y axis||Indicates how the Y axis is scaled in the trend view|
|Interpolate export||Interpolate or use latest value when missing data in export|
|Maximum fill count||Indicates how many values should be filled when missing data in export|
When logging is done with changes, trend data is logged both periodically according to trend interval, and more often if the value changes during the trend interval.