Abstract: A method of operating a diagnostic data collection device and a diagnostic data bus for an HVAC system are disclosed. In an embodiment, the diagnostic data collection device includes a diagnostic communication interface and a flexible interface module. The interface module measures electrical properties associated with an HVAC component. Electrical properties may include a sensor output and may include analog and digital signals. The diagnostic data collection device generates an exception message if the sensed property is out of specification. Evaluation rules are provided to detect various types of failures, including transient failures, steady state failures, and trending failures. The diagnostic data collection device self-calibrates by recording electrical properties during normal operation of the HVAC equipment. A plurality of diagnostic data collection devices may be coupled by a diagnostic data bug independent of the HVAC system's control bus, to ensure operational integrity of the diagnostic system.

Abstract: Methods and apparatus for improving network performance include automatically setting the activation state of a termination resistor of a network device. A network communications error rate and, optionally, the identity of the network nodes associated with the errors, is determined. The error rate is compared to threshold criteria. If the error rate exceeds a predetermined threshold, the activation state of the termination resistor is toggled. If no improvement to the error rate is detected, the termination resistor is reverted to its original activation state.

Abstract: A method of operating a diagnostic data collection device and a diagnostic data bus for an HVAC system are disclosed. In an embodiment, the diagnostic data collection device includes a diagnostic communication interface and a flexible interface module. The interface module measures electrical properties associated with an HVAC component. Electrical properties may include a sensor output and may include analog and digital signals. The diagnostic data collection device generates an exception message if the sensed property is out of specification. Evaluation rules are provided to detect various types of failures, including transient failures, steady state failures, and trending failures. The diagnostic data collection device self-calibrates by recording electrical properties during normal operation of the HVAC equipment. A plurality of diagnostic data collection devices may be coupled by a diagnostic data bug independent of the HVAC system's control bus, to ensure operational integrity of the diagnostic system.

Abstract: A diagnostic data collection device and a diagnostic data bus are disclosed. In an embodiment, the diagnostic data collection device includes a diagnostic communication interface and a flexible interface module. The interface module is configurable to measure one or more electrical properties associated with an HVAC component, such as voltage, current, resistance. Electrical properties may include a sensor output and may include analog and digital signals. The diagnostic data collection device generates an exception message if the sensed property is out of specification. Evaluation rules are provided to detect various types of failures, including transient failures, steady state failures, and trending failures. The diagnostic data collection device self-calibrates by recording electrical properties during normal operation of the HVAC equipment.

Abstract: An apparatus and method for extending component life in a motor drive having a stator heating mode is disclosed. The current supplied to stator windings is cycled through a set of primary stator power transistors to increase the overall lifespan of the drive, thus preventing premature failure of the stator power transistors by splitting the workload between them, rather than having a single transistor supply the bulk of the stator heating current.

Abstract: Methods and apparatus for improving network performance include automatically setting the activation state of a termination resistor of a network device. A network communications error rate and, optionally, the identity of the network nodes associated with the errors, is determined. The error rate is compared to threshold criteria. If the error rate exceeds a predetermined threshold, the activation state of the termination resistor is toggled. If no improvement to the error rate is detected, the termination resistor is reverted to its original activation state.

Abstract: An apparatus and method for extending component life in a motor drive having a stator heating mode is disclosed. The current supplied to stator windings is cycled through a set of primary stator power transistors to increase the overall lifespan of the drive, thus preventing premature failure of the stator power transistors by splitting the workload between them, rather than having a single transistor supply the bulk of the stator heating current.

Abstract: One embodiment is a diagnostic method for a system including setting a first diagnostic code based upon a condition of a DC bus of a variable frequency drive during a first drive state, setting at least one additional diagnostic code based upon a condition of at least one motor phase current during a second drive state, outputting first diagnostic information indicating a malfunction of the variable frequency drive if the first diagnostic code indicates a first error, and outputting second diagnostic information indicating a malfunction of a motor or a connector coupling the motor and the drive if the at least one additional diagnostic code indicates a second error.

Abstract: A diagnostic data collection device and a diagnostic data bus are disclosed. In an embodiment, the diagnostic data collection device includes a diagnostic communication interface and a flexible interface module. The interface module is configurable to measure one or more electrical properties associated with an HVAC component, such as voltage, current, resistance. Electrical properties may include a sensor output and may include analog and digital signals. The diagnostic data collection device generates an exception message if the sensed property is out of specification. Evaluation rules are provided to detect various types of failures, including transient failures, steady state failures, and trending failures. The diagnostic data collection device self-calibrates by recording electrical properties during normal operation of the HVAC equipment.

Abstract: A method and system for detecting and diagnosing faults in a heating, ventilation and air conditioning (HVAC) system includes a remote server receiving data from sensors associated with the HVAC system. The data received includes measured sensor data, from both HVAC equipment and co-located sensors, and identifying criteria for identifying the piece of equipment associated with the sensor and/or identifying a location of the sensor, which may or may not be on or in the HVAC equipment. A probability that a fault exists and/or a likelihood of occurrence of a fault in one of the pieces of the equipment is calculated based on the data received, and an alert is generated in accordance with an analysis thereof, which may include comparison of the probability and/or likelihood with predetermined threshold(s).

Abstract: One embodiment is a diagnostic method for a system including setting a first diagnostic code based upon a condition of a DC bus of a variable frequency drive during a first drive state, setting at least one additional diagnostic code based upon a condition of at least one motor phase current during a second drive state, outputting first diagnostic information indicating a malfunction of the variable frequency drive if the first diagnostic code indicates a first error, and outputting second diagnostic information indicating a malfunction of a motor or a connector coupling the motor and the drive if the at least one additional diagnostic code indicates a second error.