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<< Click to Display Table of Contents >> Trend Charts |
  
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<< Click to Display Table of Contents >> Trend Charts |
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Trend charts graph (or plot) variables with respect to time.
Use the Trend Chart menu item from the Draw Menu OR click the Trend Chart tool 
on the toolbar
Go to Drawing Basics for general instructions
After clicking the tool the cursor changes to 
Use the tool as you would to draw a rectangle. As you move the mouse the Trend chart appears:
When you release the mouse button the Trend Chart Properties box and the Variables List are displayed. Use these to set up the Trend chart.
Note: Charts from previous versions of SpecView can be converted.
For details on Runtime functionality see: Using Trend charts in Runtime Mode
The features of Trend Charts are:
| • | Back-fill of historical data when the screen (GDW) is opened. This is independent from Historical Replay. |
Note: The data points for back-fill are from logged data, so the resolution of the points is in accordance with the data logging rate.
| • | Scrollback using the scrollback thumb to view up to 10 chart widths of previous data: |
| • | Chart Notes to mark significant points on a chart. |
Chart Notes can be setup to be added automatically.
| • | Zoom - Drag an area of the chart to expand X and Y axes. The popup-menu includes options to export data in zoomed area to a CSV file. The number of intermediate values is specified on the Chart tab. |
| • | Multiple scales on the left or right of the chart, for some or all of the pens, with optional value pointers. |
| • | Popup menu - Trend charts now have a popup menu that can be accessed from Runtime Mode using either the left or right mouse buttons, for compatibility with touch-screens which don't have a 'right' mouse button. In Edit Mode the popup menu is only available using the right mouse button. This is because the left button is used to select the Trend Chart for moving and resizing. |
The new Trend Chart Properties box is accessed by either choosing Setup Chart from the popup menu or clicking the Setup button (if it is enabled) from Runtime Mode.
The Setup button is enabled from the Buttons & View tab.
Settings can be saved for future use by clicking the Save settings as default for new charts button.
A quick way to assign variables for the pens is to multiselect a number of variables from the Variables List and drag & drop them into the pens box on the Pens tab.
Pens are assigned default colors according to the whether the chart background is a light or a dark color. To change the color and settings of a specific pen select it in the pens box and click the Edit button to open the Pen Properties box, with the following tabs:
| • | Thickness setting for each pen |
| • | Decimal point setting for each pen |
| • | Preset tolerance band. Example: draws ±10° lines relative to the Working Setpoint to check for deviation. This is not currently implemented, see alternative method. |
| • | Pen trace can blink and/or change color on alarm |
| • | Automatic or fixed scaling with logarithmic option |
| • | Optional pointers for each pen on scales |
| • | Y-Axis auto scaling |
| • | Smooth Scroll – the chart scrolls to the left or downwards*; the latest value will be always shown at the right or bottom* of the chart (* depends on horizontal or vertical chart) |
| • | Jump Scroll (like SpecView Version 2) – when the last segment is full, the chart will jump one segment |
| • | No Scroll – the chart will keep expanding the time axis to fit all the data. This means the chart will show all the data, which is useful if the duration of the batch process is unknown |
| • | Time span selections (from 30 seconds to 60 days) with scroll-back management settings |
| • | Vertical scrolling chart option for compatibility with paper chart recorders |
| • | Scales for any pens, left or right |
| • | Secondary elapsed time display, which is useful for batch processes |
| • | 2 cursors showing the exact values of the pens and the differences in values between the 2 cursors |
| • | Chart notes to mark significant points on a chart. Chart Notes can also be setup to be added automatically |
| • | The pen values along the top of the chart can have additional information and be formatted in different ways. |
| • | Chart print and screen print options |
| • | Page print to printer or JPG |
| • | File name selection – fixed or from a SpecView variable |
| • | Display the chart with a dark background for clarity on the screen, but when printing use a white background to save ink |
| • | Automatic pen color assignment |
| • | Flexibility of items displayed in the top right corner of the Trend Chart |
It is also possible have a chart which plots X with respect to Y (as opposed to X with respect to Time) by using an ActiveX control, for example, by buying an ActiveX XYChart from Century Soar, see here: http://www.cstsoft.com/english/trend-gdiplus.htm. This may look similar to this:
Flashing and Hiding Trend Charts:
Trend Charts can be made to hide or flash using Color Dynamics like any other object on a screen (GDW).
Be aware that making Trend Charts flash, especially if multiple charts are flashing, may affect performance as it is CPU intensive.
Also, making a trend chart flash at the same rate as a pen line is set to blink could mean that the pen line wouldn't be visible.
However, Position Dynamics cannot be used to move Trend Charts. But using Color Dynamics to hide a chart can be used instead to make a chart seem to move.