Omron SYSMAC CS Series Operation Manual page 241

Troubleshooting the Network
Problem
PROFIBUS Master Unit is
configured. All slaves were
in data exchange, but it has
now stopped.
PROFIBUS Master Unit is
configured. After switching
the Master Unit to OPER-
ATE, the Unit itself or other
Units on the PLC CPU
showed unexpected behav-
iour.
PROFIBUS Master Unit is
configured. All slaves were
in data exchange, but all
outputs are now set to
zeros. Inputs can still be
read.
220
Probable cause
No power is supplied to the system. All LED
indicators on the system are OFF.
A PLC CPU error occurred.
• The ERH indicator is ON, the other LED
indicators are OFF.
• The ERR/ALM LED indicator on the PLC
CPU is ON.
A Unit error occurred.
• The ERC indicator is ON, the other LED
indicators are OFF.
• The ERR/ALM LED indicator on the PLC
CPU is ON.
The PROFIBUS Master Unit is in either
OFFLINE or STOP mode.
• The BST LED indicator is OFF
• The BF LED indicator is ON: A PROFIBUS
interface error has occurred: see Master
Status 2 error flags (CIO Word n+6, bit 00
~ 03, see Note) for details.
Network cabling is not correct.
• BF LED indicator is ON.
• Master Status 2 error flag may provide
more information (CIO Word n+6, bit 00 ~
03, see Note).
The I/O data mapping of the Master Unit may
overwrite either its won or other Unit CIO/DM
Areas settings:
• Master Unit operational mode changes
unexpectedly.
• Global-Control commands are transmitted
unexpectedly.
• Other Special I/O Units or Special Bus
Units change behaviour unexpectedly.
The bus parameter used on the network are
wrong.
• I/O data exchange between the Master
Unit and the PLC stops.
The Master Unit is in CLEAR mode.
• The BST LED indicator is Flashing.
• The CLEAR switch has been set in the
Switch word 1 (CIO Word n, bit 02, see
Note)
• The Unit has been configured for Auto-
CLEAR and an error occurred on the Net-
work with one or more slave devices.
Correction
• Verify that power is supplied to the sys-
tem.
• Determine error in the PLC CPU (Refer to
the CS1 Series CPU Unit Operation Man-
ual (W339) or the CJ Series CPU Unit
Operation Manual (W393)).
• Restart the Unit, and read the error log to
determine the type of error.
Determine the mode of the Unit: Check the
Master Status 1 Word (CIO Word n+5, bit 00
to bit 03, see Note). If Unit is in OFFLINE or
STOP mode:
• Verify that the master does not use the
same address as another Master Unit on
the network. Otherwise, correct the Master
Unit's PROFIBUS address.
• Set CLEAR or OPERATE switch in CIO
Word n (see Note).
Verify that the network installation is correct:
• Verify that the network is still in tact, and
connected to the Unit.
• Verify that any repeaters used are func-
tioning correctly.
Verify the I/O Mapping of the Master Unit:
• Ensure that the I/O data of the Master
Unit, does not overwrite its own CIO
words.
• Ensure that the I/O data of the Master
Unit, does not overwrite CIO words or DM
words of other Special I/O or Special CPU
Units (e.g. Ethernet Units)
Verify that the correct bus parameters have
been used.
• (If necessary) Restart the Unit and force it
to OFFLINE immediately, or
• Disconnect the network cable first and
restart the Unit.
• Download the correct Bus parameters.
• If Auto-CLEAR is enabled, correct the net-
work problem first.
• Set OPERATE switch in CIO Word n (see
Note) to force the Unit to the OPERATE
mode.
Section 7-4