Options on the Overlays tab

Lists the overlays, by snapshot name, currently available for use in the trend.

Click the

Anchor

row to toggle between

Position

and

Time

settings. The anchor aligns the overlay to the chart in the position, or time that you set.

The earliest data in the snapshot is anchored to the runtime chart based on a specified offset percentage. Runtime data scrolls under the overlay data contained in the snapshot.

The position of the overlay depends on the normal view of the trend chart. If you zoom the chart data, the X and Y ranges of the data in the snapshot change to match that of the runtime chart. If you pan the data, the runtime data moves beneath the overlay data in the snapshot — with the starting point of the overlay data remaining fixed in the chart.

Double-click the

Start

row on the

Overlays

tab to specify a starting time. The overlay data in the snapshot scrolls with the data in the runtime chart, based on the chart's refresh rate. You can set the refresh rate on the

General

tab. If you pan or zoom the data in the chart, the overlay data held in the snapshot also pans, or zooms.

Specifies a starting time, for overlays anchored by time.

Defines how far an overlay is anchored from the left edge of a runtime chart, in terms of a percentage of the total width of the chart. For example, if you anchor an overlay by position and specify an offset value of 25%, the earliest data held in the snapshot begins overlaying at a quarter of the chart width. To anchor the overlay at the left edge of the runtime chart, set the offset to 0.

Click the

Visible

row to toggle between

On

and

Off

. To show the data in the snapshot immediately when the chart opens in runtime, set

Visible

to

On

. At runtime, operators can show, or hide each overlay using the context menu. Settings on the

Runtime

tab control an operator's ability to show or hide overlays at runtime. The

Visible

setting on the

Pens

tab can also affect the visibility of any pen in an overlay.

Adding a snapshot adds all of the pens charted in the snapshot to the list of pens available in the trend. To see a list of the available pens, click the

Pens

tab. The numbers in the

First Pen

and

Last Pen

columns identify the first and last pens in the snapshot and correspond with the pen numbers on the

Pens

tab.

For example, suppose that before adding a snapshot, a trend has five pens, numbered 1 through 5. If you add a snapshot that has 3 pens, the

First Pen

column identifies the first pen as 6 and the

Last Pen

column identifies the last pen as 8. On the

Pens

tab, the 3 pens in the snapshot hold positions 6, 7, and 8 in the

Pen Attributes

spreadsheet. You can set up these pens just as you can set up any other pen in the trend.

Adds a snapshot to the trend and makes it available for use as an overlay on the runtime chart.

Removes a selected snapshot from the trend and makes it unavailable for use with an overlay on the runtime chart.

Deletes a selected snapshot.