Troubleshooting; Alarm Word And Warning Word - Danfoss VLT FC 100 Manual

VLT® FC 100 LonWorks

9. Troubleshooting

9.1. Alarm Word and Warning Word

9.1.1. Alarm and warning messages
General
There is a clear distinction between alarms and warnings. In the event of an alarm, the frequency
converter will enter a fault condition. After the cause for the alarm has been cleared, the master
must acknowledge the alarm message in order to start operation of the frequency converter again.
A warning, on the other hand, may appear when a warning condition arises, then disappear when
conditions return to normal without interfering with the process.
Alarm word and warning word are shown on the display in Hex format. If there is more than one
warning or alarm, a sum of all warnings or alarms will be shown. Warning word and alarm word
are displayed in par. 16-90 to 16-95. For more information on the individual alarms and warnings,
please refer to:
Warnings
All warnings within the frequency converter are represented by a single bit within a warning word.
A warning word is always an action parameter. Bit status FALSE [0] means no warning, while bit
status TRUE [1] means warning. Each bit status has a corresponding text string message. In
addition to the warning word message the master will also be notified via a change to bit 7 in the
status word.
Alarms
Following an alarm message the frequency converter will enter a fault condition. Only after the
fault has been rectified and the master has acknowledged the alarm message by setting bit 3 in
the Control Word, can the VLT resume operation. All alarms within the VLT are represented by a
single bit within an alarm word. An alarm word is always an action parameter. Bit status FALSE
[0] means no alarm, while bit status TRUE [1] means alarm.
VLT® HVAC Drive Design Guide
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9. Troubleshooting
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