373
Checking Operations of CS-series and CJ-series Master Units
Section 6-3
Operations
6-3-5
Troubleshooting
When an error occurs, the indicators of the Master Unit connected to a CS-
series or CJ-series PLC will indicate the error. Check the Master Unit's indica-
tors and perform the error processing described in the following table.
When an error occurs in a Slave, the Slave can be identified from the status of
the Master’s indicators (refer to page 76) or from the status flags (refer to
page 365) in the PLC’s Special I/O Unit Area.
d
c
D20004
TST (350)
#F
#0002
JMP (004)
#0002
JME (005)
c
D20004
TST (350)
#0
d
Bit 15 (Error Flag)
Bit 00 (Registration Completed Flag)
Registered
Slaves joined
network
Error
detected
Slave I/O processing program
Error detected
Registered
Slaves joined
network
When bit 15 of D20004 is ON, work bit c
(error detected) turns ON.
When bit 00 of D20004 is ON, work bit d
(registered Slaves joined network) turns
ON.
Slave I/O is processed when JMP condition
is ON only.
If the JMP condition is OFF, the program
jumps to JME and Slave I/O is not
processed.
Error
Probable cause
Possible remedy
The Master Unit’s
RUN indicator is
OFF
The PLC’s power is OFF.
Turn the PLC’s power supply ON.
The same unit number has been set
on another Special I/O Unit, causing
an area overlap error in the PLC.
Check that the same unit number is not used by more than
one Special I/O Unit and restart the PLC. In particular, when
the usable node number setting is IN0 to IN15 and OUT0 to
OUT15, check that the next unit number after the one set on
the Master Unit is not set on another Special I/O Unit.
The unit number has been set outside
the specified range, causing an area
overlap error in the PLC.
Check that the unit number is set within the range specified
for Special I/O Units and restart the PLC.
CS-series and CJ-series PLCs
Unit numbers 0 to 95 can be set when the Master Unit is
using 10 words as a single Special I/O Unit and the usable
node number setting is IN0 to IN7 and OUT0 to OUT7 (DIP
switch pin 1 OFF).
Unit numbers 0 to 94 can be set when the Master Unit is
using 20 words as two Special I/O Units and the usable node
number setting is IN0 to IN15 and OUT0 to OUT15 (DIP
switch pin 1 ON).
The usable node number setting was
changed with the PLC power ON, and
the Master Unit was restarted only.
Turn the PLC OFF and then ON again, and recreate the I/O
tables.
A Special I/O Unit error occurred in
the PLC because the Master Unit is
not connected securely.
Turn the PLC OFF, make sure that the Master Unit is
mounted correctly, and then turn the PLC ON again. Replace
the Master Unit if the error recurs.
The Master Unit is faulty.
Replace the Master Unit.
Communications stop mode is set.
Communications stop when a communications error occurs
in communications stop mode. Remove the cause of the
error, and then reset the Master Unit using the PLC’s Restart
Bit or turn the PLC OFF and then ON again.