Trend Charts > Trend Chart Runtime Mode

Trend Chart features available in Runtime Mode include:

Pause

•	To pause the chart right-click and choose Pause Chart from the popup menu. The scroll-thumb will scroll as the pens are drawn. However, the chart will resume when the scroll-back screens have been filled.

Zoom

•	Click and drag an area of the chart to expand X and Y axes, and choose Zoom to area & pause from the popup menu.

TrendCharts_Zoom

•	The number of intermediate values used to fill in the pen trace lines when the chart is zoomed is specified on the Chart tab of the Trend Chart Properties box.

•	The chart will pause until scrollback space is full.

•	The popup-menu includes Export Range to CSV to export the data in the zoomed area to a CSV file. The CSV file will be full resolution including the intermediate values.

•	The zoomed chart will pause until the chart and any scrollback screens are filled, at which point the zoomed chart will continue scrolling automatically. The reason for this is to conserve computer memory.

•	To un-zoom a chart click and choose Zoom->Back from the popup menu.

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The difference between real-time & Historical Replay is that zooming a chart while in Historical Replay will not fill in the intermediate values, because these are not logged. Therefore the resolution of the chart will be the data logging rate as opposed to using the intermediate values stored for zooming.

Note: Zooming a Trend Chart is separate from zooming a GDW. This is because zooming a GDW will not expand the trend chart and fill in the zoomed pen traces with the intermediate values.

An example of zooming:

If the chart is 2 hours wide with 10 scrollback screens which is currently showing data from 10:00 to 12:00 and the part of the trend to be zoomed is the 10 minutes from 10:15 to 10:25, then the middle of the this range is therefore 10:20.

The Scrollback thumb will be repositioned to the middle of that range, which in this example is 10:20, and there will be 5 scrollback screens to the left of center, going back 5 x 10 mins to 09:20, and 5 scrollback screens to the right of center, going forward 5 x 10 mins = 11:10.

Therefore, when zoomed-in there are +/- 5 screens to the left/right of the center of the zoomed time period.

To see the detail beyond those 5 screens, exit zoom to go back to normal and re-zoom elsewhere.

However, there are exceptions to this:

Assuming the same 2 hour chart as described above, 10:00 to 12:00 with a current time of 12:00

To zoom in on the final 10 minutes - 11:50 to 12:00, there are no screens to the right as there is no data available yet, so the 10 scrollback screens will be positioned to the left.

Note: The number of scrollback screens in Zoom mode is the same as the number of scrollback screens in un-zoomed mode. Therefore, if there are 6 scrollbacks, then there will be +/- 3 around the center. However, if the Realtime chart has less than 3 scrollbacks (e.g. 0) a new value of 4 is used for the duration of zooming (so there will be +/- 2).

Back fill

•	Trend charts are back filled with logged data when they are opened. It is necessary to select Start on Right on the Trend Chart Properties Chart tab for the back-filling to work.

Note: A Trend Chart will only be able to be 'back filled' if there is some logged data.

Note: If there are no scroll-back screens specified on the Chart tab and if the chart is set to Start on Left, then back filled data will not be seen.

Scrollback

•	Trend charts can be scrolled back using the scrollback thumb along the time axis. The settings for this are specified on the Chart tab of the Trend Chart Properties box.

Cursors

•	Trend chart cursors are 2 cursors that can be positioned on the chart to show the exact values of the pens and the differences in values between the 2 cursors.

•	Cursors can be placed by a single right-click on the chart to place the first cursor and double-right-click to place the second cursor.

•	Alternatively use left-click on the chart and choose 'Place cursor 1' or 'Place Cursor 2' from the popup menu

•	To clear the cursors left-click on the chart and choose 'Remove cursor(s)' from the popup menu

Chart Notes

•	Chart notes are used to mark significant points on a chart. Chart Notes can also be setup to be added automatically

•	Chart notes that are not assigned to a pen will be seen on all trend charts.

Trend Chart Pen Scales

•	If the trend chart only has one value scale, then to see the scale of any of the other pens, click the pen labels along the top. However, this will only become noticeable if the Pens have different scales and/or colors because the scale and color will change too.

Note: If, for example, there are 4 pens but only 3 scales have been added then it will not be possible to see the scale of the 4th pen. Therefore either have just one scale, or have a scale for each pen.

Auto-open on Runtime

This menu command on the Edit Mode File menu should be used if a project has more than one GDW defined which contain Trend Chart(s).

In this case the menu command should be used on each of the GDW's to ensure that their traces start whenever SpecView goes into Runtime Mode.

NOTE: Be sure to click this menu command if the GDW has a Trend chart. If you do not, the GDW will have to be opened in Runtime Mode before the Trend chart will start.