Rockwell Automation 1771-DE Absolute Encoder Module User Manual - Manual (Page 40)

Chapter
6
6Ć1
Troubleshooting
In this chapter you will read how to troubleshoot your absolute encoder
module using the ACTIVE (GREEN) and FAULT (red) indicators,
block-transfer rungs in your ladder program, and diagnostic bits in word 2
of the read-data file.
The following table lists problems indicated by LED changes, possible
causes, and recomended actions.
LED = ON LED = OFF
Indication Description Recommended Action
ACTIVE
FAULT
Normal operation; module should operate
when the PC goes into the RUN mode and
you send presets.
None
ACTIVE
FAULT
Module is held reset at powerĆup; probable
malfunction in adapter module or processor
module.
Substitute adapter module, power supply, or
processor module.
ACTIVE
FAULT
Module has detected a hardware fault in its
powerĆup diagnostic routine.
Return module for repair.
ACTIVE
FAULT
Module is not receiving DC power from the
chassis backplane.
Check chassis power supply (ies).
Observe the block-transfer rungs in your ladder diagram program. You
have a block-transfer error when you observe one or both of the
following:
The block-transfer error bits are intensified (PLC-3 processors).
The enable and done bits of block-transfer instructions do not intensify
or they remain intensified; they should alternately turn on (intensify)
and turn off.
Block-transfer errors are caused if one or more of the following are
incorrect:
The module’s location (rack, group, slot) in the I/O chassis must match
the rack, group, and slot of block-transfer instructions in the ladder
program.
Chapter Objectives
Causes of BlockĆtransfer Errors
@
@
@
@