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Checking Slave Operations
Section 6-5
Indicator Meanings The following table shows the meaning of the common indicators.
Indicator Status for Errors The following table shows the status of the common indicators when an error
occurs. Check the Master’s indicators to determine the node number of the
Slave in which the error occurred. The Slave’s node number will also be indi-
cated in the status area (not provided in CQM1 Master Units) allocated in the
Special I/O Unit Area of the Master Unit.
Errors Limited to Analog Terminals
Indicator Color Status Meaning
PWR
(POWER OUT)
Green ON The communications power supply is ON.
OFF The communications power supply is OFF.
COMM Yellow ON Normal communications
OFF A communications error has occurred or the Unit
is in standby status.
ERR
(BUS/S ERR)
Red ON A communications error has occurred.
OFF Normal communications or the Unit is in standby
status.
Situation Indicator status Probable cause Possible remedy
PWR COMM ERR
Slave’s power OFF OFF OFF OFF The Slave’s power is OFF. Turn the Slave’s power supply ON.
Data area overlap ON OFF ON With a CQM1 Master that’s “num-
ber of points/node number” set-
ting is set to 4, the same area may
be allocated to more than one
Slave. Communications will be
stopped.
Check the area allocated to the 8-
point Slave where the error
occurred, eliminate the area over-
lap, and then restart the PLC.
Address over error ON ON OFF With a CQM1 Master that’s “PLC
word allocation” setting is 2 or 4
words, an out-of-range node num-
ber from 0 to 7 may have been set.
Check the Master’s indicators to
determine the node number and set
the node number within the speci-
fied range.
Node number out-of-
range error
ON OFF OFF With a CQM1 Master, an out-of-
range node number from 8 to 15
may have been set.
When a CS-series, C200HX/
C200HG/C200HE-(Z)E, and
C200HS Master Unit, CS-series
Master Unit, or CJ-series Master
Unit is used and the range of
usable node numbers is from 0 to
7, there are Slaves whose node
numbers are set between 8 and
15.
Check the Master’s indicators to
determine the node number and set
the node number within the speci-
fied range.
Communications
mode conflict
ON OFF OFF The communications mode set-
ting of the Master Unit does not
match that of the Slave.
Make the communications mode of
the Master Unit and Slave agree,
then power-up the Master Unit
again.
Communications error ON OFF ON An error has occurred with a Slave
during communications and it is
withdrawn from the system.
Check the Master’s indicators and
clear the cause of the communica-
tions error.
Master’s power OFF ON OFF --- The Master’s power is OFF. Turn ON the Master’s power supply.
Situation Indicator status Probable cause Possible remedy
RUN COMM ERR U.ERR
Analog Terminal Error ON OFF OFF ON An error has occurred in inter-
nal circuits of the CPU, ana-
log-digital converter or digital-
analog converter, etc.
Power-up the Slave again. If
the Slave does not return to
normal, replace it.
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