Mitsubishi Electric MELSEC iQ-R Series User Manual page 487

Error code Error
(hexadecima
l)
7F68H Framing error
7F69H Parity error
7F6AH Buffer full error
7F6BH CD(DCD) signal
control error
7F6CH Transmission
error
7F9AH System error
7FABH System error
System error
7FC7H
7FC9H to System error
7FCCH
Description Signal
name
• The stop bit settings do SIO
not match.
• A malfunction occurred on
the line because the
power for the target
station was ON/OFF.
• Noise occurs on the line.
• During multidrop
connection, two or more
devices transmitted data
at the same time.
• The parity bit settings do P/S
not match.
• A malfunction occurred on
the line because the
power for the target
station was ON/OFF.
• Noise occurs on the line.
• During multidrop
connection, two or more
devices transmitted data
at the same time.
• The operating system SIO
receive buffer overflowed
and received data was
skipped.
• Data was received when CHn
the CD(DCD) signal is ERR.
OFF with the CD terminal
check enabled.
• Data cannot be sent CHn
because the line is not ERR.
connected.

• The operating system of
C24 detected some error.

• The operating system of
C24 detected some error.
• The operating system of 
C24 detected some error.

• The operating system of
C24 detected some error.
Corrective action Protocol
MC
• Match the settings of C24 with 
that of the target device.
• Clear the error information by
'Error initialization request'
(YE).
In addition, when
communicating data with the
nonprocedural protocol,
execute the INPUT
instruction, and read and
discard the unnecessary data.
• Take measures against noise.
• During multidrop connection,
provide the interlock so that
data will not be transmitted
simultaneously by multiple
devices.
• Match the settings of C24 with 
that of the target device.
• Clear the error information by
'Error initialization request'
(YE).
In addition, when
communicating data with the
nonprocedural protocol,
execute the INPUT
instruction, and read and
discard the unnecessary data.
• Take measures against noise.
• During multidrop connection,
provide the interlock so that
data will not be transmitted
simultaneously by multiple
devices.
• Use the DTR and DC controls 
and perform data
communications so that the
buffer does not become full.
(Perform RS/CS control when
the modem function is used.)
• When the reception data read
request signal turns ON,
execute read operation
immediately.

• Review the CD(DCD) signal
control of the target device.
(Data is sent when the
CD(DCD) signal is ON.)
• Perform data communications
with the CD terminal check
disabled.

• Send data after line
connection processing on the
interface side that uses the
modem function.
Page 490 Corrective actions
for system error
Page 490 Corrective actions
for system error
Page 490 Corrective actions
for system error
Page 490 Corrective actions
for system error
Nonpr Bidire Prede
ocedu ctiona fined
ral l
  
  
  
  
 
27 TROUBLESHOOTING
485
27.4 Error Code List
27