History Comparison chart

Use this chart type to compare multiple assets and their historical data values in a single chart.

In the Configure this chart properties, you can select to view data in two formats: as raw, actual data (actual data items and values as they were sampled) or interval data (data interpolated to show a trend of data values over time).

o Maximum Samples (all values) - this chart shows historical values as actual data values captured in the past. Instead of specifying Start and Interval times (as you would do for viewing interval historical values), you specify a start and end time, and the number of samples when you read these values. The platform retrieves all data values logged to the Platform that fall between the Start and End Times up to the threshold value specified by the maximum number of samples.

o Interval - this chart shows an interpolated replay of historical values. The Platform uses the specified start time and sample values to calculate and return values for each interval, interpolating the values in its database to match your requested intervals.

You can modify the format and layout of the chart to show data generated in other timeframes, to show the data aligned or overlapping, and so on.

Annotation chart

In addition to viewing historical asset data, you can track user actions for the assets in the annotation chart. Any annotations (notes, events, alarms, actions) that occurred in the Platform in the same timeframe as the history chart appear in the annotations chart. You can point to a specific charted annotation to view its properties. You can add a new note as an annotation; this will be saved to the Platform with the assets' information (see below for "How to add data markers for strip chart displays").

Procedures for History comparison charts

In addition to the operations you can perform on all charts, operations specific to the History comparison charts include those described below. Click the title to display the procedure; click the title again to hide the procedure.

To specify the format for the chart

1. Under Configure this chart, select the asset(s) and data item(s) to show in the window. To select multiple assets or data items, press SHIFT or CTRL and select the items.

2. Type the start and end times for the data values to show in the window.

3. Do one of the following:

§ Select Max. Samples and type the maximum number of data points per data item to show in the chart (for a raw data/actual history replay).

OR

§ Select Interval and type the number of minutes' worth of data values to show in the chart.

For example, the following settings show asset values logged from 10 days ago until yesterday.

$image\example_historytrendsettings.gif$

4. Select whether to display the charted data values on aligned or overlapping y-axes.

5. Click Refresh. The chart is redrawn with the properties you specify. Note that the selected time is set to the middle of the chart window.

To view information in the annotation chart

1. Set the start and end times for the database / asset activity you want to track. (See step 1 of "How to specify the format for the chart".)

2. View the annotation markers as they appear in the annotation table. The markers identify the following:

$image\serviceapp_annotations_explained.gif$

3. Point to an annotation marker to view its properties.

To add and remove data markers for strip chart displays

1. Set the start and end times for the Platform / asset activity you want to track. (See step 1 of "How to specify the format for the chart".)

2. In the chart display, click where you want to add a data marker. The marker appears on the closest data point. You can add up to two markers per chart display.

3. To add a second marker, right-click the chart.

4. To move either marker, click in the chart with the related mouse button. For example, to move the first marker, click the destination point with the left mouse button: to move the second marker, click with the right mouse button.

5. To clear all data markers, press SHIFT and click in the chart display.

6. Now you can add notes to each marker to identify its importance. Each marker note is saved to the Platform, with the corresponding asset.

a. For a selected marker, click $image\serviceapp_chartnewmarkernote.gif$ above the annotation chart.

b. In the displayed Add Note Dialog, type the note you want to add for the marker and click OK.

7. To clear all data markers, press SHIFT and click in the chart display.

Tip

Aligned value display is useful if the values are of the same units; Overlapping value display is most useful if the values are of different units.