Systems and methods for using rule-based fault detection in a building management system

1. A method for detecting faults in a building management system, the method comprising:

at a computer of the building management system, using a stored rule condition to detect a first fault in the building management system, the stored rule condition utilizing a stored threshold value;

using the computer to determine whether to adjust the stored threshold value based on at least one of fault detection data or building management system performance data, wherein determining whether to adjust the stored threshold value comprises identifying a frequency with which the first fault is detected when the stored threshold value is used in the stored rule condition and comparing the identified frequency with a stored frequency value, wherein the computer determines to adjust the stored threshold value in response to the identified frequency exceeding the stored frequency value;

determining a new threshold value for the stored rule condition in response to a determination to adjust the stored threshold value;

adjusting the stored rule condition to utilize the new threshold value by replacing the stored threshold value with the new threshold value, wherein the stored threshold value is replaced with the new threshold value in response to a determination to adjust the stored threshold value and wherein the stored threshold value is not replaced with the new threshold value in the absence of a determination to adjust the stored threshold value; and

at the computer, using the adjusted rule condition to detect a second fault in the building management system.

2. The method of claim 1 , further comprising causing a graphical user interface to be displayed on an electronic display device, the graphical user interface configured to receive a new threshold value as user input, wherein the rule condition is adjusted in response to the user input.

3. The method of claim 1 , wherein a processing circuit completes the determining and adjusting steps automatically and without user input.

4. The method of claim 1 , wherein the new threshold value is determined by comparing the stored threshold value to an estimated error for a measurement value obtained from a sensor.

5. The method of claim 1 , wherein the new threshold value is determined by comparing an estimated power consumption of a controlled device to an actual power consumption of the controlled device.

6. The method of claim 1 , wherein the rule condition comprises a trigger condition and a content condition, and wherein using the adjusted rule condition to detect a fault in the building management system further comprises checking the trigger condition to determine whether to process the content condition.

7. The method of claim 6 , wherein the trigger condition includes one or more criteria for determining whether to process the content condition, and wherein the content condition includes one or more criteria for comparing a parameter of the building management system with a threshold value;

wherein using the adjusted rule condition to detect a fault further comprises:

in response to a determination that the trigger condition is satisfied, detecting a fault by processing the content condition; and

in response to a determination that the trigger condition is not satisfied, not processing the content condition.

8. The method of claim 1 , wherein the fault detection data comprises a history of detected faults and the computer determines the new threshold value such that the adjusted rule condition results in a reduced fault detection frequency relative to the identified frequency.

9. The method of claim 1 , wherein the computer of the building management comprises at least one of a master controller and a second controller that is controlled by a master controller, the method further comprising:

at the second controller, collecting building equipment data from building equipment and using the collected building equipment data to control the building equipment;

at the second controller, processing the collected building equipment data relative to a rule condition;

at the second controller, detecting a fault in the building equipment based on the processing of the collected building equipment data relative to the rule condition; and

reporting the detected fault to the master controller from the second controller.

10. A method for detecting faults in a building management system, the method comprising:

using a master controller to control a second controller;

at the second controller, collecting building equipment data from building equipment and using the collected building equipment data to control the building equipment;

at the second controller, processing the collected building equipment data relative to a rule condition, wherein the rule condition utilizes a stored threshold value;

at the second controller, detecting a fault in the building equipment based on the processing of the collected building equipment data relative to the rule condition;

reporting the detected fault to the master controller from the second controller

determining whether to adjust the stored threshold value based on at least one of fault detection data or building management system performance data, wherein determining whether to adjust the stored threshold value comprises identifying a frequency with which the fault is detected when the stored threshold value is used in the rule condition and comparing the identified frequency with a stored frequency value;

determining a new threshold value for the stored rule condition in response to a determination that the identified frequency exceeds the stored frequency value;

adjusting the stored rule condition to utilize the new threshold value by replacing the stored threshold value with the new threshold value, wherein the stored threshold value is replaced with the new threshold value in response to a determination that the identified frequency exceeds the stored frequency value and wherein the stored threshold value is not replaced with the new threshold value in the absence of a determination that the identified frequency exceeds the stored frequency value; and

using the adjusted rule condition to detect a second fault in the building management system.

11. The method of claim 10 , wherein the second controller is an equipment controller that directly controls the building equipment.

12. The method of claim 10 , wherein the rule condition is selectively used based on an operational state of at least one of the building equipment and the second controller.

13. The method of claim 10 , wherein the second controller conducts the collecting, processing, and detecting steps without querying or receiving data from the master controller, another upstream controller, or a downstream controller.

14. The method of claim 10 , wherein the second controller is an air handling unit controller and the collected building equipment data comprises sensor and actuator data for an air handling unit.

15. The method of claim 10 , wherein the second controller is a lowest level controller of the building management system.

16. The method of claim 10 , wherein the rule condition comprises a trigger condition and a content condition; and wherein using the adjusted rule condition to detect a fault in the building management system further comprises checking the trigger condition to determine whether to process the content condition.

17. The method of claim 16 , wherein the trigger condition includes one or more criteria for determining whether to process the content condition, and wherein the content condition includes one or more criteria for comparing a parameter of the building management system with a threshold value;

wherein using the adjusted rule condition to detect a fault further comprises:

in response to a determination that the trigger condition is satisfied, detecting a fault by processing the content condition; and

in response to a determination that the trigger condition is not satisfied, not processing the content condition.

18. The method of claim 10 , further comprising:

determining a need for a threshold adjustment of the rule condition; determining a new threshold value for the rule condition; and adjusting the rule condition to utilize the new threshold value.

19. A method for detecting faults in a building management system, the method comprising:

recalling a stored rule at a computer of the building management system;

identifying, by the computer, a trigger condition and a content condition for the stored rule, wherein the trigger condition includes one or more criteria for determining whether to process the content condition, and wherein the content condition includes one or more criteria for comparing a parameter of the building management system with a threshold value, wherein at least one of the trigger condition and the content condition utilizes a stored threshold value;

checking, by the computer, the trigger condition to determine whether to process the content condition;

in response to a determination that the trigger condition is satisfied, detecting, by the computer, a fault by processing the content condition;

in response to a determination that the trigger condition is not satisfied, not processing the content condition;

determining whether to adjust the stored threshold value based on at least one of fault detection data or building management system performance data, wherein determining whether to adjust the stored threshold value comprises identifying a frequency with which the fault is detected when the stored threshold value is used in the rule condition and comparing the identified frequency with a stored frequency value;

determining a new threshold value for the stored rule condition in response to a determination that the identified frequency exceeds the stored frequency value;

adjusting the stored rule condition to utilize the new threshold value by replacing the stored threshold value with the new threshold value, wherein the stored threshold value is replaced with the new threshold value in response to a determination that the identified frequency exceeds the stored frequency value and wherein the stored threshold value is not replaced with the new threshold value in the absence of a determination that the identified frequency exceeds the stored frequency value; and

using the adjusted rule condition to detect a second fault in the building management system.

20. The method of claim 19 , wherein the trigger condition is a time delay based on an amount of time needed for a controller to reach a steady state, and wherein the checking step comprises delaying processing of the content condition for the time delay specified by the trigger condition.

21. The method of claim 19 , wherein the trigger condition is based on an operational state of a controller, and wherein the checking step comprises:

recalling a current operational state of the controller from a finite state machine within the controller; and

comparing the trigger condition to the current operational state of the controller.

22. The method of claim 19 , wherein the trigger condition is stored within a library of predefined trigger conditions in a memory;

wherein the content condition is stored within a library of predefined content conditions in a memory;

wherein the method comprises building a rule by selecting (a) at least one trigger condition from the library of predefined trigger conditions and (b) at least one content condition from the library of predefined content conditions.

23. The method of claim 19 , further comprising:

recalling a trigger condition from a library of predefined trigger conditions; recalling a content condition from a library of predefined content conditions; causing a graphical user interface to be displayed on an electronic display

device, the graphical user interface configured to receive user input;

associating the trigger condition and the content condition to form a rule in

response to the user input; and

storing the rule in a memory.

24. The method of claim 19 , wherein the computer of the building management comprises at least one of a master controller and a second controller that is controlled by a master controller, the method further comprising:

at the second controller, collecting building equipment data from building equipment and using the collected building equipment data to control the building equipment;

at the second controller, processing the collected building equipment data relative to a rule condition;

at the second controller, detecting a fault in the building equipment based on the processing of the collected building equipment data relative to the rule condition; and

reporting the detected fault to the master controller from the second controller.