Troubleshooting I/O Communication - Omron WS02-9094G - V1.0 Operation Manual

Troubleshooting the Network
4-2-3

Troubleshooting I/O Communication

Communication Problems
Problem
PROFIBUS Master Unit is
configured, but none of the
slaves are exchanging
data.
This section deals with troubleshooting the I/O communication on the network
from a behaviour point of view. The column on the left describes the general
perceived problem to the user. The columns on the right list the possible
causes and their remedies.
Probable cause
No power is supplied to the system.
• All LED indicators on the system are OFF.
A PLC CPU (startup) error occurred.
• The ERH indicator is ON, the other LED
indicators are OFF.
• The ERR/ALM LED indicator on the PLC
CPU is ON.
The stored configuration contains a check-
sum error (storing configuration was inter-
rupted or failed).
• After restarting the Unit, the ERC LED
indicator is ON, and the PRM LED indica-
tor is OFF.
• Unit Status error flag may provide more
information (CIO Word n+4, bit 06, bit 07,
bit 09, see Note).
The configuration contains timing errors.
• After restarting the Unit, the ERC LED
indicator is ON, and the PRM LED indica-
tor is OFF.
The PROFIBUS Master Unit is in either
OFFLINE or STOP mode.
• The BST LED indicator is OFF
The Unit may have been configured to
maintain its current mode (last mode was
OFFLINE, during download).
• 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).
• CIO Words n+9 to n+16 show which
slaves have problems.
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)).
• Re-download the configuration.
• If the problem persists, replace the Unit.
• Verify that the Bus parameter sets are cor-
rect.
• Re-download the configuration.
• If the problem persists, replace the Unit.
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).
• Change the configuration to set the Unit
OPERATE mode when switching the PLC
to RUN/MONITOR mode (see Master
DTM, Master Setup Tab). Download the
configuration, and switch the PLC to RUN/
MONITOR mode.
Verify that the network installation is correct:
• Verify that all slaves are powered up and
functioning correctly.
• Verify that all slave devices are correctly
connected to the network.
• Verify that any repeaters used are func-
tioning correctly.
• Check the cable length versus the
selected baud rate.
• Verify that any stubs used are not too
long.
• Verify that termination (resistors and
inductors) are properly set and used.
Section 4-2
121