Fault queue – Rockwell Automation 20G PowerFlex 750-Series AC Drives User Manual

Page 163

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Rockwell Automation Publication 750-RM002B-EN-P - September 2013

163

Diagnostics and Protection

Chapter 3

The following data/conditions are captured and latched into non-volatile drive
memory.

P952 [Fault Status A]
P953 [Fault Status B]
Indicates the occurrence of conditions that have been configured as faults.

P954 [Status1 at Fault]
P955 [Status2 at Fault]
Captures operating conditions of the drive at the time of the fault.

P957 [Fault Amps]
Motor amps at the time of the fault.

P958 [Fault Bus Volts]
DC Bus volts at time of the fault.

P956 [Fault Frequency]
Output Hertz at the time of fault.

P962 [AlarmA at Fault]
P963 [AlarmB at Fault]
Captures and displays P959/960 [Alarm Status A/B] at the last fault.

Fault Queue

Faults are also logged into a fault queue such that a history of the most recent
fault events is retained. Each recorded event includes a fault code (with associated
text) and a fault “time of occurrence.” PowerFlex 750-Series drives have a 32 event
queue.

The fault queue records the occurrence of each fault event that occurs while no
other fault is latched. Each fault queue entry includes a fault code and a time
stamp value. New fault events are not logged to the fault queue if a previous fault
has already occurred, but has not yet been reset. Only faults that actually trip the
drive are logged. No fault that occurs while the drive is already faulted is logged.

The fault queue is a first-in, first-out (FIFO) queue. Fault queue entry 1 is always
the most-recent entry (newest). Entry 32 is always the oldest. As a new fault is
logged, each existing entry is shifted by one. The previous entry 1 moves to entry
2, previous entry 2 moves to entry 3, and so on. If the queue is full when a fault
occurs, the oldest entry is discarded.

The fault queue is saved in nonvolatile storage at power loss and its content
retained when power is cycled.

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