On-Line Monitoring and Fault Detection.
On-Line Monitoring and Fault Detection.
(669 K)
Seem, J. E.; House, J. M.; Monroe, R. H.
ASHRAE Journal, Vol. 41, No. 7, 21-26, July 1999.
Keywords:
monitors; control loops; control system performance;
heating; ventilation; air conditioning; equations; fault
detection
Abstract:
Modern energy management and control systems have alarm
and trend features that allow building operators to
monitor and troubleshoot building systems. The alarm
feature can provide nearly immediate feedback when, for
instance, a sensor value is outside specified limits.
Using the trend feature, building operators can view
graphs of sensor and controller output versus time. In
the case of an alarm, information obtained using the
trend feature can assist the operator in isolating the
cause of the alarm. However, it can be difficult to
select the alarm limits. If the limits are too narrow,
the building control system likely will issue a number
of false alarms and building operators eventually will
ignore them. If the limits are too wide, faulty
conditions will tend to go unnoticed because alarms are
not issued.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899