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Chapter Objectives
Indication
ACTIVE
FAULT
ACTIVE
FAULT
ACTIVE
FAULT
ACTIVE
FAULT
Causes of Block transfer Errors
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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
Description
Normal operation; module should operate
when the PC goes into the RUN mode and
you send presets.
Module is held reset at power up; probable
malfunction in adapter module or processor
module.
Module has detected a hardware fault in its
power up diagnostic routine.
Module is not receiving DC power from the
chassis backplane.
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.
6
Chapter
LED = OFF
Recommended Action
None
Substitute adapter module, power supply, or
processor module.
Return module for repair.
Check chassis power supply (ies).
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