Omron C200HW-CLK21 Operation Manual page 308

Troubleshooting Using Indicators
Troubleshooting with LNK and M/A Indicators
Data Link Cannot be
Started
Indicators
RUN ERC ERH INS
Lit --- --- Not lit Terminating resistance is
The following table describes the LNK and M/A indicators at the startup node
and their use in troubleshooting when a data link cannot be started.
Starting a data link depends on the Controller Link Unit operating normally
and participating in the Network. Refer to Troubleshooting with RUN, ERC,
ERH and INS Indicators earlier in this section and check Unit operation before
using the following table.
Probable cause
not set correctly.
Cables are not connected
correctly.
The node address is larger
than the maximum node
address set for the network
parameters.
No other nodes exist.
No nodes have been set as
polling nodes.
The same operating level
is set more than once for
the same PLC.
The Bus Connection Unit
has become loose.
The set baud rate is differ-
ent to other nodes.
Section 9-1
Probable remedy
Turn ON the terminating
resistance at the nodes at
both ends of the Network
and turn it OFF at all other
nodes.
Check the cable connec-
tions and reconnect cor-
rectly.
Either reset the maximum
node address using the
Controller Link Support
Software or reset the node
address to below the maxi-
mum.
Ensure that 2 or more
nodes exist within the Net-
work.
Refer to 8-1-2 Setting the
Polling and Polled Nodes
and set at least one polling
node. (Controller Link
Units should normally be
set as polling nodes.)
Reset so that each operat-
ing level is used only once.
Tighten the mounting
screws on the Bus Con-
nection Unit (C200HX/HG/
HE PLCs only).
Refer to SECTION 4 Prep-
arations for Communica-
tions and set all nodes on
the network to the same
baud rate.
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