Abstract: The present invention relates to a diagnostic system for use in a network control system. The diagnostic system is preferably utilized to analyze HVAC system or VAV box performance in an environmental control system such as a network facilities management system. The diagnostic system advantageously records temperature, air flow, and actuator position data in the controller associated with the VAV box and calculates an exponentially weighted moving average value. The exponentially weighted moving average value may be related to error values, process output values, change in actuator position, actuator position, duty cycle of the actuator, or starts, stops and reversals of the actuator. Such a system allows a person to analyze VAV boxes and controller performance over a particular timely period and the lifetime of the system. Box and damper warnings may be provided by the diagnostic system when the EWMA values are over or under particular threshold values.

Abstract: The present invention relates to a diagnostic system for use in a network control system. The diagnostic system is preferably utilized to analyze VAV box performance in an environmental control system such as a network facilities management system. The diagnostic system advantageously allows the serviceperson to perform diagnostic tests on VAV boxes from a remote location. Flat box warnings, starved box warnings, box excessive damper hysteresis warnings, oversized box warnings, damper stroke out of bounds warnings, as well as other box and damper warnings may be provided by the diagnostic system. Preferably, the diagnostic system formats the air flow data so that it can be displayed for graphing. The diagnostic system causes individual controls to adjust the damper positions. Air flow parameters for each position are communicated to the remote location.