Select the Model Expression button in the Add Expression Overrides dialog to use visual baselining for testing threshold scenarios and use the results to create an expression override for the situation.
Use any of these methods to see values and adjust the display:
- Move the mouse pointer over a point to see the value and time stamp.
- Drag the window border to expand the chart width.
- Drag the border bar between the chart and the Attributes area up or down.
- Click
Zoom in (Ctrl
+ Click) and drag the mouse over the time period to highlight; the
selection expands to fill the chart area. Click 
Zoom out (Esc)
to return to the full data view. - Select options in the Time Span area to reduce the time span and thus the number of samples displayed.
- Click
, 
, or 
to redraw the data as a bar chart, plot chart
(the default), or area chart.
Expressions
This area shows the values of the current expression override, one row for each expression. Initially, these are the same values used in the reference formula (the original situation formula).
- If you want to delete an expression, select the check box and click Remove Expression. If you delete all the expressions, click Add Expression to add the reference formula.
- You can specify a schedule condition for an expression in two
ways:
- Select Click here to assign an override
schedule. Select a defined schedule from the list or
create a new schedule (see Select Override Expression Schedule).
- Click
the Select an area in the chart to
create a schedule for in the toolbar. Drag the mouse from
left to right or from right to left to highlight the time range when
the schedule should run. After you release the mouse button, a new
expression row is added with a daily schedule defined for that time
period, which is expressed on the chart as a shaded area. (See example.)
- Select
- A defined schedule is indicated by
for a schedule that runs on specific days or for a schedule that runs daily within the specified time
period. - Column headings
- These are the names of the attributes referenced in the situation. Any attributes on the left side of the divider are designated as display items for the situation and can be used as an override condition. The override expression is applied only when the comparisons you specify are true. The attribute on the right side of the divider are the comparison values for the expression being modeled. These values are used instead of those in the reference formula when the override condition is true, or if no override condition is set.
- Click inside a comparison value cell on the right side of the divider to see only that attribute plotted on the chart and to edit the value.
- After you edit a value and press Enter, the cell has a
blue background
to indicate it has changed from the original value. A line is drawn
across the chart to represent the current comparison value. A shaded
region appears above or below this marker line if the relational operator
represents a range of trigger values (>, >=, <, <=). - If you click inside a blue cell and change the value, it is plotted in the chart automatically. This enables you to fine tune a threshold value and observe the affected values in the chart.
- If you click another object (such as a Time Span or Function field)
while an attribute cell is active, the cell is highlighted in
yellow. If you click a
point in the chart area, the value where you clicked is inserted in
the cell.
Functions
This area is displayed when the attribute group used in the situation has historically collected values. Click a cell in the Expressions area to enable the Functions area, and select the check box for the statistical function to use. Optionally enter a value in the Argument field and click Recalculate to see the adjusted threshold in the Result field and plot it on the chart as a colored line.- AVG
- For the selected attribute, calculate the average value from the samples taken during the time period, and add or subtract the standard deviation that was entered in the Argument field. Valid values are -6 to 6.
- MIN
- For the selected attribute, find the lowest sampled value within the time period, and increase or decrease that value by the percentage that was entered in the Argument field. Valid values are -100 to 100.
- MAX
- For the selected attribute, find the highest sampled value within the time period and increase or decrease that value by the percentage that was entered in the Argument field. Valid values are -100 to 100.
- PERCENTILE
- For the selected attribute, find the value below which NUM percent of the data points fall; where NUM is the value from the Argument field. Valid values are 1 to 100.
- MODE
- For the selected attribute, find the most frequently observed value within the time period. No argument is entered for a MODE calculation.
Copy - Add the value from the Result cell to the selected cell in the Attributes area.
Chart options- Modify the appearance of the threshold: Visible
in legend to add Threshold to the legend, Show chart
label to add a threshold label, and Fill Style to
change the threshold pattern or color. Click Custom Colors to
choose from a wider selection of colors or to create your own (see Custom Color).
Time Span
This area is displayed when the attribute group used in the situation has historically collected values. The Last 24 Hours is shown by default.- Last
- You can change from the default 24 hours to a different value or unit of time (Hours, Days, Weeks, Months, Quarters, Years).
- The Time Column field shows the attribute for the time stamp, such as Recording Time.
- Custom
- Use the Custom tab to plot a specific date range or to select a different time attribute.
- Click inside the Start Time and End Time fields to select a date and time.
- The Time Column field shows the attribute for the time stamp, such as Recording Time.
- Daily
- Use the Daily tab to plot a specific time range.
- Click inside the Start Time and End Time fields to select a date and time.
- Select the
Show
data for last 
check
box and specify the number of days to plot. - Select
calendar
day to include any weekend days that fall within the date
range; or 
weekdays to
exclude weekend days. For example, if today is Monday and you select
the last 2 weekdays, Thursday and Friday of the past week are plotted. - Select the Show
this day's data check box to select a specific date
to plot within the time range.
Buttons
- Recalculate
- Click Recalculate after you have entered an argument for a statistical function to see the result in the Result column and plotted on the chart. Use this button also to refresh the chart with any changes you make to the time span selection or override key conditions.
- OK
- Click OK to close the dialog and use the values from the Expressions area for the expression override.
- Reset
- After you click inside an attribute cell, the chart is redrawn to plot only that attribute. If you also select a statistical function and click Recalculate, the statistical result is also plotted. Click Reset to redraw the chart with all attributes.
- These are all the reset actions taken:
- Cancel any attribute selection in the table
- Clear any shaded threshold area in the chart
- Show all chart series if any were not visible
- Remove all statistical markers from the chart
- Clear the Function fields, including function results
- Cancel any zooms in progress
- Disable the create schedule action
- Cancel
- Click Cancel to exit the dialog without saving your changes.
Example
This example shows a daily schedule over three days that applies the override >= 75 from 01:00 to 06:00.