Trend Tool – Configuring a Date Range

Note: You can change configuration settings for this tool in Run mode. However, these settings usually only persist for the current runtime session. When you close the CygNet Studio screen on which the tool resides, the tool settings may revert to those originally configured in Edit mode.

The Data page enables you to define time range and time behavior settings for a trend.

Example Trend Tool Data Page

Data Page Properties

The following table lists and describes Data page properties.

Property	Description
View Window
Absolute View	Check this box to enable the absolute time options. If left unchecked, time options are relative. Relative Time: This means that the time settings you define are relative to the current time. The range is bounded by Earliest Date and View Size options. Absolute Time: This means that the time settings you define make up a fixed range that might or might not include the current time. The range is bounded by Earliest Date and Latest Date options. See also AbsoluteDateRange.
Current Time Source	Specifies the source of the current date and time used to define the limits of the view window. Options are as follows: 0 - Client Time: Specifies that the view window is created relative to the client current time. Best practice strongly recommends ensuring that all relevant servers and clients are synchronized to the same time. 1 - Server Time: Specifies that the view window is created relative to the server (i.e., ARS) current time. If this setting is used but the server time is unavailable, the client time is used for as long as the server time is unavailable. Best practice strongly recommends ensuring that all relevant servers and clients are synchronized to the same time. 2 - Series Time: Specifies that the view window is created relative to the most recent time supplied by a series, server, or client. This means that if any series time on a trend is the most recent time of the three possible time sources, the series defines the latest extent of the view window and appears to be in the future. May be used as a way of correcting for time drift or other similar anomalous situations where series data appears to be "ahead" of the local current time.
Earliest Date	The options available to this property vary depending on whether Absolute View is enabled or not. In either case, Earliest Date sets the starting date and/or time for a trend. See also EarliestDate and EarliestDateCount.
Latest Date	This property sets the absolute ending data and time for a fixed time window for a trend.
View Size	This property specifies the relative time range to display on a trend. See also ViewSizeCount and ViewSizeUnits.
Scroll by	This property displays the number and time unit by which you can scroll forwards and backwards through a Trend Tool.
Auto Extend
Enable	Check to enable Auto Extend. If enabled, the Auto Extend property provides a method for the trend to request new data at a specified interval. This gives the appearance that the trend is trending data at a real-time pace. If disabled, a trend is populated once with data from the Value History Service (VHS). See also AutoExtendEnabled.
Refresh Rate (sec)	This property specifies the number of seconds to wait before an auto-extended trend refreshes. It takes precedence over the value specified in the TheView’s [UpdateInterval] property. See also AutoExtendRateSec.
Other
Show Unreliable Values	Displays unreliable values. By default, unreliable values are not displayed. See also ShowUnreliable.
Extend Last Value	Select this option to extend a series from its latest plotted point up to the latest time displayed on the trend. If used in combination with Auto Extend, a horizontal line is dynamically drawn forward into trend time until the next plotted point generates. See also ExtendLastValue.
Use Alternate Units	If enabled, displays the series in alternate units as specified in the Point Service (PNT) point record. By default, series are displayed in primary units. If a point is not configured for alternate units, a message is displayed indicating so. See also AlternateUnits.

Property

Description

View Window

Absolute View

Check this box to enable the absolute time options. If left unchecked, time options are relative.

Relative Time: This means that the time settings you define are relative to the current time. The range is bounded by Earliest Date and View Size options.
Absolute Time: This means that the time settings you define make up a fixed range that might or might not include the current time. The range is bounded by Earliest Date and Latest Date options.

See also AbsoluteDateRange.

Current Time Source

Specifies the source of the current date and time used to define the limits of the view window.

Options are as follows:

0 - Client Time: Specifies that the view window is created relative to the client current time. Best practice strongly recommends ensuring that all relevant servers and clients are synchronized to the same time.
1 - Server Time: Specifies that the view window is created relative to the server (i.e., ARS) current time. If this setting is used but the server time is unavailable, the client time is used for as long as the server time is unavailable. Best practice strongly recommends ensuring that all relevant servers and clients are synchronized to the same time.
2 - Series Time: Specifies that the view window is created relative to the most recent time supplied by a series, server, or client. This means that if any series time on a trend is the most recent time of the three possible time sources, the series defines the latest extent of the view window and appears to be in the future. May be used as a way of correcting for time drift or other similar anomalous situations where series data appears to be "ahead" of the local current time.

Earliest Date

The options available to this property vary depending on whether Absolute View is enabled or not. In either case, Earliest Date sets the starting date and/or time for a trend. See also EarliestDate and EarliestDateCount.

Latest Date

This property sets the absolute ending data and time for a fixed time window for a trend.

View Size

This property specifies the relative time range to display on a trend. See also ViewSizeCount and ViewSizeUnits.

Scroll by

This property displays the number and time unit by which you can scroll forwards and backwards through a Trend Tool.

Auto Extend

Enable

Check to enable Auto Extend. If enabled, the Auto Extend property provides a method for the trend to request new data at a specified interval. This gives the appearance that the trend is trending data at a real-time pace. If disabled, a trend is populated once with data from the Value History Service (VHS). See also AutoExtendEnabled.

Refresh Rate (sec)

This property specifies the number of seconds to wait before an auto-extended trend refreshes. It takes precedence over the value specified in the TheView’s [UpdateInterval] property. See also AutoExtendRateSec.

Other

Show Unreliable Values

Displays unreliable values. By default, unreliable values are not displayed. See also ShowUnreliable.

Extend Last Value

Select this option to extend a series from its latest plotted point up to the latest time displayed on the trend. If used in combination with Auto Extend, a horizontal line is dynamically drawn forward into trend time until the next plotted point generates. See also ExtendLastValue.

Use Alternate Units

If enabled, displays the series in alternate units as specified in the Point Service (PNT) point record. By default, series are displayed in primary units. If a point is not configured for alternate units, a message is displayed indicating so. See also AlternateUnits.