Mitsubishi Electric MELSEC iQ-RJ71C24-R4 - Page 487

27 TROUBLESHOOTING
27.4 Error Code List
485
27
7F68H Framing error • The stop bit settings do
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.
SIO • 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.

7F69H Parity error • The parity bit settings do
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.
P/S • 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.

7F6AH Buffer full error • The operating system
receive buffer overflowed
and received data was
skipped.
SIO • 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.

7F6BH CD(DCD) signal
control error
• Data was received when
the CD(DCD) signal is
OFF with the CD terminal
check enabled.
CHn
ERR.
• 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.

7F6CH Transmission
error
• Data cannot be sent
because the line is not
connected.
CHn
ERR.
• Send data after line
connection processing on the
interface side that uses the
modem function.

7F9AH System error • The operating system of
C24 detected some error.
Page 490 Corrective actions
for system error
7FABH System error • The operating system of
C24 detected some error.
Page 490 Corrective actions
for system error
7FC7H
System error • The operating system of
C24 detected some error.
Page 490 Corrective actions
for system error
7FC9H to
7FCCH
System error • The operating system of
C24 detected some error.
Page 490 Corrective actions
for system error
Error code
(hexadecima
l)
Error Description Signal
name
Corrective action Protocol
MC Nonpr
ocedu
ral
Bidire
ctiona
l
Prede
fined