Rockwell Automation 1756-XXXX ControlLogix Digital I/O Modules User Manual

Page 82

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82

Rockwell Automation Publication 1756-UM058G-EN-P - November 2012

Chapter 4

Diagnostic Module Features

The following illustration provides an overview of the fault reporting process for
digital output modules.

Module-fault Word

Fuse Blown Word

Field-power Loss Word

1756-OA8D only

Bit 31

Bit 0

A no load condition for any point sets the bit for that point in the no
load word and also sets the appropriate bit in the module-fault word.

A blown fuse for any point sets the bit for that point in the fuse blown word and
also sets the appropriate bits in the module-fault word.

A communications fault sets all bits in the module-fault word. A fuse blown,
field-power loss, no load or output verify condition sets the appropriate bit in
the module-fault word.

No Load Word

Output Verify Word

A loss of field power from any group sets the bit for that point in the field-power
loss word and also sets the appropriate bits in the module-fault word.

An output verify condition for any point sets the bit for that point in the output
verify word and also sets the appropriate bit in the module-fault word.

1

Group 0

1

1

1

1

1

Group 1

1

1

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