OPERATION MANUAL CompoBus/S

Checking Operations of CS-series and CJ-series Master Units Section 6-3
Error Probable cause Possible remedy
The Master Unit’s
ERH indicator is
ON
A Slave Unit’s
COMM indicator
is OFF or its ERR
indicator is ON
The I/O table is not registered. Recreate the I/O tables.
The same unit number has been set
on another Special I/O Unit.
The unit number has been set outside
the specified range.
The CPU Unit is faulty. Replace the CPU Unit.
An error has occurred at the Master
Unit.
The Slave cannot participate in communications
because its power supply
is OFF. (The Slave’s PWR indicator is
OFF.)
The Slave cannot participate in communications
because there is a problem
with the Slaves’ power supply.
The Slave cannot participate in communications
because its power supply
is inadequate.
The Slave cannot participate in communications
because there is a problem
with the communication cable
connection or the cable itself.
The same node number is used on
another Slave between inputs Slaves
or between output Slaves.
A Slave’s number has been set to 8 to
15 even though the usable node number
setting is IN0 to IN7 and OUT0 to
OUT7.
Communications modes of Master
Unit and Slave do not match.
A common system mistake has been
made. (Refer to the table on page 376
for a list of common mistakes.)
Check that the same unit number is not used by more than
one Special I/O Unit and turn the PLC OFF and ON again. 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.
Check that the unit number is set within the range specified
for Special I/O Units and turn the PLC OFF and ON again.
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).
Check the Master Unit’s indicators and follow the procedures
listed above.
Turn ON the Slave’s power supply.
The Slave Unit is faulty. Replace the Slave Unit.
The area used by the Analog Terminal
or 32-point Connector Terminal
exceeds the range of the Master Unit
I/O Area.
Check the power supply cable connections and connect the
cables to the Slaves correctly.
Check the power supply capacity. If it is inadequate, either
change the system configuration or change the power supply
so that sufficient power is provided.
Check the connections and cable. Replace the communications
cable if it is faulty.
Change one of the Slave’s node number settings to eliminate
the duplication and then turn the Slaves ON again. Either
reset the Master Unit with the PLC’s Restart Bit or turn the
PLC OFF and then ON again.
Either change the Input and Output Slave’s node number settings
so that they are 0 to 7 or change the usable node number
setting to IN0 to IN15 and OUT0 to OUT15.
Set the communications mode so that it is the same as that of
the Master Unit.
Refer to the table on page 376 for common mistakes and
their remedies.
Change to node numbers that do not exceed the I/O Area
range, then turn ON the PLC again.
375