383
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withdrawn from the system.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.