381
Checking Operations of CQM1 Master Units
Section 6-4
The Master Unit’s ERC
indicator is ON
Power is not being supplied to the Slaves.
Turn ON the Slave’s power supply.
There is a problem with the Slaves’ power
supply.
Check the power supply cable connections and
connect the cables to the Slaves correctly.
The Slaves’ power supply is inadequate.
Check the power supply capacity. If it is inade-
quate, either change the system configuration or
change the power supply so that sufficient power
is provided.
There is a problem with the communication
cable connection or the cable itself.
Check the connections and cable. Replace the
communications cable if it is faulty.
There is a non-existent node number
because a Slave’s node number was
changed after communications were estab-
lished.
Either reset the Master Unit with the PLC’s Restart
Bit or turn the PLC OFF and then ON again.
The same node number is set on two or
more Input Slaves or Output Slaves.
After changing the Slaves’ node number settings
to eliminate the duplication, turn the Slaves ON
again and then turn the PLC ON again.
A common system mistake has been made.
(Refer to the table on page 382 for a list of
common mistakes.)
Refer to the table on page 382 for common mis-
takes and their remedies.
A Slave Unit is faulty.
Replace the faulty Slave Unit.
A Slave Unit’s COMM
indicator is OFF or its
ERR indicator is ON
An error has occurred at the Master Unit.
Check the Master Unit’s indicators and follow the
procedures listed above.
The Slave cannot participate in communica-
tions because its power supply is OFF. (The
Slave’s PWR indicator is OFF.)
Turn ON the Slave’s power supply.
The Slave cannot participate in communica-
tions because there is a problem with the
Slaves’ power supply.
Check the power supply cable connections and
connect the cables to the Slaves correctly.
The Slave cannot participate in communica-
tions because its power supply is inade-
quate.
Check the power supply capacity. If it is inade-
quate, either change the system configuration or
change the power supply so that sufficient power
is provided.
The Slave cannot participate in communica-
tions because there is a problem with the
communication cable connection or the
cable itself.
Check the connections and cable. Replace the
communications cable if it is faulty.
The node address set for the Slave is out-
side the setting range.
When outside the setting range with the
node addresses 0 to 7: ERS indicator of the
Master Unit flashes
When outside the setting range with the
node address 8 to 15: ERS indicator of the
Master Unit goes OFF
Change the node address of the Slave that
caused the address over or change the Master
Unit’s PLC word allocation setting (pins 1 and 2)
and max. number of Slaves setting (pin 3) so that
the Slave’s node number is acceptable.
Refer to
for a table showing
all of the possible DIP switch settings.
The same node number is set on two or
more Input Slaves or Output Slaves.
Change one of the Slave’s node number settings
to eliminate the duplication, turn the Slave ON
again, and then turn the PLC ON again.
Communications modes of Master Unit and
Slave do not match.
Set the communications mode so that it is the
same as that of the Master Unit.
A common system mistake has been made.
(Refer to the table on page 382 for a list of
common mistakes.)
Refer to the table on page 382 for common mis-
takes and their remedies.
The Slave Unit is faulty.
Replace the Slave Unit.
Error
Probable cause
Possible remedy