Management system user interface for comparative trend view

1. A method for creating a comparative trend view in a graphical user interface of a building management system comprising the steps of:

maintaining a system manager application in a data processing system of a management system configured to perform building management system functions and to provide a graphical user interface;

running the system manager application;

displaying a trend view chart on the graphical user interface using a trend view definition selected by a user;

acquiring trend data associated with the trend view definition from a trend database in the data processing system, the trend data values comprising measured values from a building automation system device acquired over a first time period;

populating the trend view chart with the trend data values associated with the trend view definition;

displaying a predefined comparative trend view button on the graphical user interface;

displaying a comparative trend view chart on the graphical user interface next to the trend view chart based on the trend view definition of the trend view chart upon selection of the predefined comparative trend view button by the user;

displaying one or more predefined time offset buttons on the graphical user interface, wherein selection of one of the one or more predefined offset buttons creates an offset time period of the comparative trend view chart from the trend view chart based on a time interval specified by the one or more predefined offset buttons, and wherein the predefined offset buttons include an option to change the offset time period between forward in time and backwards in time;

acquiring historical trend data values from the trend database in the data processing system based on the offset time period selected by the user, the historical trend data values comprising measured values from the same building automation system device acquired over a second time period that is offset from the first time period by the offset time period; and

populating the comparative trend view chart with the historical trend data values; and

in response to receiving a change in a time range represented by the trend view chart, automatically updating the comparative trend view chart according to the change in the time range and the offset time period.

2. The method of claim 1 further comprising the step of displaying an area on the graphical user interface for entry of a time offset.

3. The method of claim 1 , wherein the comparative trend view chart is displayed immediately above the trend view chart.

4. The method of claim 1 , wherein the predefined offset buttons are offset by one day, offset by one week, offset by one month, and offset by one year.

5. The method of claim 1 , wherein the offset time period is manually entered by the user.

6. The method of claim 1 , wherein the comparative trend view chart is a time offset of the trend view chart.

7. A non-transitory computer-readable medium encoded with executable instructions that is configured to run in a data processing system of a management system, configured to perform building management system functions, and configured to provide a graphical user interface capable of:

displaying a trend view chart on the graphical user interface using a trend view definition selected by a user;

acquiring trend data values associated with the trend view definition from a trend database in the data processing system, the trend data values comprising measured values from a building automation system device acquired over a first time period;

populating the trend view chart with the trend data values associated with the trend view definition;

displaying a predefined comparative trend view button on the graphical user interface;

displaying a comparative trend view chart on the graphical user interface next to the trend view chart based on the trend view definition of the trend view chart upon selection of the predefined comparative trend view button by the user;

displaying one or more predefined time offset buttons on the graphical user interface, wherein selection of one of the one or more predefined offset buttons creates an offset time period of the comparative trend view chart from the trend view chart based on a time interval specified by the one or more predefined offset buttons, and wherein the predefined offset buttons include an option to change the offset time period between forward in time and backwards in time;

acquiring historical trend data values from the trend database in the data processing system based on the offset time period selected by the user, the historical trend data values comprising measured values from the same building automation system device acquired over a second time period that is offset from the first time period by the offset time period; and

populating the comparative trend view chart with the historical trend data values.

8. A method for creating a comparative trend view in a graphical user interface of a building management system comprising the steps of:

maintaining a system manager application in a data processing system of a management system configured to perform building management system functions and to provide a graphical user interface;

running the system manager application;

displaying a comparative trend view chart and a trend view chart next to the comparative trend view chart on the graphical user interface, both based on a trend view definition, in response to a user selection;

displaying one or more predefined time offset buttons on the graphical user interface, wherein selection of one of the one or more predefined offset buttons creates a selected offset time period of the comparative trend view chart from the trend view chart based on a time interval specified by the one or more predefined offset buttons, and wherein the predefined offset buttons include an option to change the offset time period between forward in time and backwards in time;

acquiring historical trend data values from the data processing system comprising measured values of at least one building automation system device based on the selected offset time period; and

populating the comparative trend view chart with the historical trend data values associated with the offset time period and with current data values received from the at least one building automation system device, wherein the current data values are displayed in the trend view chart.

9. A data processing system, comprising:

a storage device comprising a system manager application;

an accessible memory comprising instructions of the system manager application;

a processor configured to execute the instructions of the system manager application to:

perform building management system functions and to provide a graphical user interface;

display a trend view chart on the graphical user interface using a trend view definition selected by a user;

acquire trend data values associated with the trend view definition from a trend database in the data processing system, the trend data values comprising measured values from a building automation system device acquired over a first time period;

populate the trend view chart with the trend data values associated with the trend view definition;

display a predefined comparative trend view button on the graphical user interface;

display a comparative trend view chart on the graphical user interface next to the trend view chart based on the trend view definition of the trend view chart upon selection of the predefined comparative trend view button by the user;

display one or more predefined time offset buttons on the graphical user interface, wherein selection of one of the one or more predefined offset buttons creates an offset time period of the comparative trend view chart from the trend view chart based on a time interval specified by the one or more predefined offset buttons, and wherein the predefined offset buttons include an option to change the offset time period between forward in time and backwards in time;

acquire historical trend data values from the trend database in the data processing system based on the offset time period selected by the user, the historical trend data values comprising measured values from the same building automation system device acquired over a second time period that is offset from the first time period by the offset time period; and

populate the comparative trend view chart with the trend data values from the sensor for the building automation system device associated with the offset time period.

10. The data processing system of claim 9 wherein an area for entry of a time offset is provided on the graphical user interface.

11. The data processing system of claim 9 , wherein the comparative trend view chart is displayed immediately above the trend view chart.

12. A data processing system, comprising:

a storage device comprising a system manager application;

an accessible memory comprising instructions of the system manager application;

a processor configured to execute the instructions of the system manager application to:

perform building management system functions and to provide a graphical user interface;

display a comparative trend view chart on the graphical user interface populated with trend data values from a trend view chart based on a trend view definition of the trend view chart, in response to a user selection, the comparative trend view chart corresponding to measurements taken from a building automation system device acquired over a first time period;

display one or more predefined time offset buttons on the graphical user interface, wherein selection of one of the one or more predefined offset buttons creates a selected offset time period of the comparative trend view chart from the trend view chart based on a time interval specified by the one or more predefined offset buttons, and wherein the predefined offset buttons include an option to change the offset time period between forward in time and backwards in time;

acquire historical trend data values from the data processing system based on the selected offset time period, the historical trend data values comprising measured values from a same building automation system device acquired over a second time period that is offset from a first time period by the offset time period; and

populate the comparative trend view chart with the acquired historical trend data values.

13. The data processing system of claim 12 wherein an area for entry of a time offset is provided on the graphical user interface.

14. The data processing system of claim 12 , wherein the comparative trend view chart is displayed immediately above a trend view chart.