Controller Link Units Operation Manual
301
Status Area and Troubleshooting Section 9-2
Data Link Status: First Data Link Status Word + 0 to + 15
Note Refer to 5-4 Checking Data Link Status for details on status flags.
Troubleshooting with Status Flags
Data Link Status
Node 2
Node 4
Node 6
Node 8
Node 10
Node 12
Node 14
Node 16
Node 18
Node 20
Node 22
Node 24
Node 26
Node 28
Node 30
Node 32
PLC status 
0: Inactive (user program not running)
1: Active (user program running)
Communications error (data link reception)
0: Normal
1: Error
PLC's CPU Unit error 
0: Normal
1: Error
Data link participation
0: Not in data link or data link inactive
1: In data link
Offset error
0: Normal
1: Error
Error: Offset exceeds 
number of send words.
Insufficient (short) receive area 
0: Sufficient
1: Insufficient
Insufficient: Receive 
area is smaller than 
send area. Excess data 
is truncated; other data 
is received.
Remaining receive area
0: Not remaining
1: Remaining
Remaining: Receive 
area is larger than send 
area. Data is received 
and remaining words 
are cleared.
Node 1
Node 3
Node 5
Node 7
Node 9
Node 11
Node 13
Node 15
Node 17
Node 19
Node 21
Node 23
Node 25
Node 27
Node 29
Node 31
Bit status Probable cause Probable remedy
PLC’s CPU Unit error is 1: 
ON
A fatal PLC error, non-fatal 
PLC error, or a watchdog 
timer error has occurred.
Refer to the PLC’s opera-
tion manual and correct 
the error. If the error occurs 
again, replace the PLC.
The Unit is mounted to a 
non-compatible PLC.
Refer to 1-2-4 Controller 
Link Unit Models and PLCs 
and mount onto the correct 
PLC.
Communications error is 1: 
ON
The relevant node is not in 
the Network.
Enter the node in the Net-
work.
A communications error 
has occurred as a result of 
noise.
Conduct an echoback test 
using the Controller Link 
Support Software and if 
this does not correct the 
error, check the usage 
environment.
A communications error 
has occurred.
Refer to page 276 Trouble-
shooting with RUN, ERC, 
ERH and INS Indicators 
and troubleshoot accord-
ingly.










