PREVNEXT

brandLogo: alt="EnergyLogo"

About the Point Trending Report

This report allows the user to choose single or multiple points and trend the values over a specified time period. Either analog or digital points can be trended and multiple variables can be selected to be in the report.

For a visual representation of two point values, you can view the points on a scatter plot. If you would like to perform a statistical analysis identifying correlation coefficient and standard deviation between these two variables, you have the ability to select a single point for the X-axis and another for the Y-axis.

If a point group has been charted, it is presented as a single point value. The Point Trending Report gives users the ability to easily aggregate and disaggregate points. When viewing an aggregated point, the user can right-click on the point to change the graphical display between a single aggregated curve and multiple disaggregated curves. When in a disaggregated state, the total or aggregated curve remains with all underlying points below it.

Figure 4-13 Point Trending Report Example.

Baseline

Baseline Period is the set of data values, within the trended log, by which all the rest of the data is compared. This allows you to compare a data value against itself at another period of time (i.e., Main kWh for last week vs. Main kWh for the same week in the previous year). You can select a predefined start date from the Period list (Custom Period, Same Start Date, 1 Week Prior, 1 Month Prior, or 1 Year Prior) then select how many days worth of original data are in the baseline period. The software takes that defined number of days and repeats the baseline period for the entire charted time.

The following procedure describes how to set the baseline parameters for reports that allow detailed baseline parameters.

Setting the Baseline Parameters.

  1. Once you have selected points to be charted, along with a date range, click Show Details to define the baseline parameters.
  2. From the data point list, select the point that you wish to use as a baseline.

  1. Define the baseline period by selecting a common period from the Period list or by manually defining the baseline period.
  2. Select a color for the baseline trend from the Baseline Color list and choose a Display option to complete the Baseline Period setup:

Time Lag

Sometimes there is a time lag between cause and effect: it takes some time for the building system to react to a temperature change. In this case we can make dependence more pronounced if we would use temperature measured some time prior to measurement of the consumption value. This time shift is a lag. By varying lag we can get the highest possible correlation between two variables.

Figure 4-14 Plotted values for a 30 minute time lag setting.

So you can use the Lag setting to make the software adjust the compared data points by shifting correlated values in degrees of Days, Hours, or Minutes.

Creating a Point Trending Report.

To create a Point Trending Report, do the following:

Start the Point Trending Report

  1. Launch shortBrandName from your browser using the following URL: http://hostname/eas
    where hostname is the name or IP address of the Web Supervisor.
  2. Enter appropriate login information to gain access to the home page.
  3. From the shortBrandName home page, open Point Trending by clicking on the Point Trending link.
  4. Click on New. You may need to enter security information for the Java plug-in.

    Note: If you desire, from within an existing report, it is easier to simply use the Goto Reports Pull-down menu on the upper right to select the desired report.

Select the Data Points to Chart

  1. Expand the tree to find the site and data point you wish to chart. Right click on the data point and select Add to Report. You will see the data point in the Selection window.

    Note: If you select a site or a meter and do an Add to Report, the software will aggregate all data points of the same type that are subordinate to that selection.

  2. Repeat adding data points or copying and pasting data points until you have all of the points in the report that you want to chart.

Set Report Parameters

  1. In the Period frame, select the time period for the data and which days of the week to exclude from the report (if any).
  2. Set Rollup Interval in days, hours, and minutes.
    The interval defines a block of time within which the data samples will be reported. Depending on the type of data, the data samples are handled differently. For demand data, the highest value sample, or peak, collected within the interval will be used. For consumption data, all the samples within the interval will be added together. For all other data types, the data samples are averaged together.
  3. In the Normalization frame, set your desired parameters. If you want to normalize for Floor area, for weather, or production, refer to "Types of Normalization", for details.
  4. Set the Correlation attributes, if desired:
    Correlation
    The scatter plot in point trending allows you to see and estimate how two data points depend upon each other. A correlation coefficient (r) can go from 0, meaning no dependency, to 1, meaning a direct correlation and dependence between the two points.

You can define which point is on the X axis and which point is on the Y axis. You can also lag the scatter plot of Y for any period of days, hours, and minutes.
  1. Click on Run Report.
  2. Point Trending Report Sample Exercise
Figure 4-15 Point Trending Report Sample.
shortBrandName
PREVNEXT