Technique for monitoring performance of a facility management system

• US 6,389,331 B1
• Filed: 03/11/1999
• Issued: 05/14/2002
• Est. Priority Date: 03/11/1999
• Status: Expired due to Term

• Current Assignee: Johnson Controls, Inc. (Johnson Controls International plc), Johnson Controls Technology Company (Johnson Controls International plc)
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Jensen, Howard A., Seem, John E.
• Primary Examiner(s): Grant, William
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US09/266,667
• Time in Patent Office: 1,160 Days
• Field of Search: 700/2, 700/3, 700/9, 700/10, 700/83, 700/275, 700/276, 700/277, 700/286, 700/19, 700/79, 709/224, 709/226, 345/969, 345/965, 236/49.5, 62/93, 621/26, 702/182-186, 702/188
• US Class Current: 700/275
• CPC Class Codes: G05B 23/0213 Modular or universal configuration of the monitoring system, e.g. monitoring system having modules that may be combined to build monitoring program; monitoring system that can be applied to legacy systems; adaptable monitoring system; using different communication protocols
• CPC Class Codes: G05B 23/0221 Preprocessing measurements, e.g. data collection rate adjustment; Standardization of measurements; Time series or signal analysis, e.g. frequency analysis or wavelets; Trustworthiness of measurements; Indexes therefor; Measurements using easily measured parameters to estimate parameters difficult to measure; Virtual sensor creation; De-noising; Sensor fusion; Unconventional preprocessing inherently present in specific fault detection methods like PCA-based methods

Abstract

A facilities management system is subdivided into a plurality of subsystems. The performance of the system is monitored by producing data which denotes a plurality of operational parameters for each of the subsystems. From that data, a global performance index is derived for each subsystem, thus providing an indication of each subsystem'"'"'s performance. The global performance indices are employed to produce a universal performance index for the entire facilities management system. This provides a hierarchy of data which enables an operator to quickly determine the overall performance of the facilities management system and each subsystem, and if warranted the operator can step through the data to identify malfunctioning components.

Claims

1. A method for monitoring performance of a facilities management system, the method comprising steps of:

(a) subdividing the facilities management system into a plurality of subsystems;

(b) producing numerical data denoting status of a plurality of operational parameters for each of the plurality of subsystems;

(c) normalizing the data to produce normalized data;

(d) for a given one of the plurality of subsystems, averaging the normalized data acquired during a period of time for a given one of the plurality of operational parameters;

(e) repeating step (d) for all of the plurality of operational parameters for the given one of the plurality of subsystems, thereby producing a plurality of averaged data;

(f) repeating steps (d) and (e) for all of the plurality of subsystems;

(g) arithmetically producing a separate global performance index for each of the plurality of subsystems from the plurality of averaged data, thereby producing global performance indices; and

(h) deriving a universal performance index from the global performance indices, wherein the universal performance index qualitatively denotes performance of the facilities management system.

2. The method as recited in claim 1 wherein the step of averaging the normalized data comprises computing exponential moving weighted averages.

3. The method as recited in claim 2 wherein the exponential moving weighted average is computed according to the expression:

{tilde over (P)}t={tilde over (p)}<sub>t−

T</sub>+λ

(P_t−

{tilde over (P)}<sub>t−

T</sub>), where {tilde over (P)}_t is an exponential moving weighted average of normalized data parameter P at time t, {tilde over (P)}<sub>t−

T</sub> is an exponential moving weighted average of the normalized data item P at a prior time t−

T, λ

is an exponential smoothing constant, and P_t is a normalized data item at time t.

4. The method as recited in claim 1 wherein the step of arithmetically producing a global index selects a worst case data average for each of the plurality of subsystems.

5. The method as recited in claim 1 wherein the step of arithmetically producing a global index comprises for each of the plurality of subsystems averaging the averaged data.

6. The method as recited in claim 1 wherein the step of arithmetically producing a global index comprises for each of the plurality of subsystems computing a weighted average of the averaged data.

7. The method as recited in claim 6 wherein computing the weighted average {overscore (P)}_t is computed according to the expression:

$\stackrel{\_}{P_t}=\frac{w_1<br><br>{\tilde{P}}_{1,t}+w_2<br><br>{\tilde{P}}_{2,t}+\mathrm{\dots <br><br>}+w_n<br><br>{\tilde{P}}_{n,t}}{w_1+w_2+\mathrm{\dots <br><br>}+w_n}$

where the P^˜

_1,t is the value of parameter P₁ at time t, P^˜

_2,t is the value of parameter P₂ at time t, P^˜

_n,t is the value of parameter P_n at time t where n is an integer, and w₁, w₂, and w_n are numerical values of weight assigned each parameter.

8. The method as recited in claim 1 wherein the step of deriving a universal performance index comprises selecting a worst case data average from among the plurality of subsystems.

9. The method as recited in claim 1 wherein the step of deriving a universal performance index comprises averaging the plurality of global indices.

10. A method for monitoring performance of a facilities management system, the method comprising steps of:

(a) subdividing the facilities management system into a plurality of subsystems;

(b) producing data denoting a plurality of operational parameters for each of the plurality of subsystems;

(c) deriving a global index from the data for the plurality of operational parameters for a given one of the plurality of subsystems, wherein the global index is a numerical value which qualitatively denotes performance of the given one of the plurality of subsystems;

(d) repeating step (c) for other ones of the plurality of subsystems to produce a plurality of global indices; and

(e) deriving a universal performance index from the global indices, wherein the global index is a single variable which qualitatively denotes performance of the facilities management system.

11. The method as recited in claim 10 wherein the step of producing data comprises normalizing the data for each of the plurality of operational parameters.

12. The method as recited in claim 10 wherein the step of producing data comprises averaging data occurring during a period of time for each of the plurality of operational parameters.

13. The method as recited in claim 12 wherein the step of producing data comprises computing exponential moving weighted averages.

14. The method as recited in claim 12 wherein the step of producing a global index selects a worst case data average for each of the plurality of subsystems.

15. The method as recited in claim 10 wherein the step of deriving a global index comprises averaging the data denoting the plurality of operational parameters for the given one of the plurality of subsystems.

16. The method as recited in claim 15 wherein the step of deriving a universal performance index comprises selecting a worst case data average from among the plurality of subsystems.

17. The method as recited in claim 10 wherein the step of deriving a universal performance index comprises averaging the plurality of global indices.