Mitsubishi Melsec-L Series User Manual page 297

Error code
Error
(Hexa-
decimal)
7F67 Overrun error
H
7F68 Framing error
H
7F69 Parity error
H
7F6A Buffer full error
H
CD(DCD) signal
7F6B
H
control error
7F6C Transmission error
H
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Description
• The C24 received the next data before
it completed receive processing of the
previous data.
• Data does not match the stop bit
setting.
• A malfunction occurred in the network
because the power source of the
partner station was on or off.
• Noise occurs in the network.
• When the multidrop was connected,
data was transmitted simultaneously by
multiple devices.
• Data does not match the parity bit
setting.
• A malfunction occurred in the network
because the power source of the
partner station was on or off.
• Noise occurs in the network.
• When the multidrop was connected,
data was transmitted simultaneously by
multiple devices.
• OS receive buffer overflowed and
receive data was skipped.
• Data was received when CD(DCD)
signal is OFF when "CD terminal check
designation" set to "Check".
• Data cannot be sent because the line is
not connected.
Signal
Corrective action
name
• Decrease the data transmission rate
and restart data communications.
• Check whether a temporary stop has
occurred in the station to which the C24
is installed. (It can be checked at special
SIO
register SD1005.) If a temporary stop has
occurred, remove its cause.
• Perform the registration, read, and
delete to the flash ROM while the data
communication is not performed.
• Match the C24 and external device
settings.
• Clear the error information according to
the ERR. clear request (YE/YF).
In addition, when communicating data
with the nonprocedural protocol,
SIO execute the INPUT instruction, and
read and discard the unnecessary data.
• Measure the noise.
• When connecting the multidrop, remove
the interlock so that data will not be
transmitted simultaneously by multiple
devices.
• Match the C24 and external device
settings.
• Clear the error information according to
the ERR. clear request (YE/YF).
In addition, when communicating data
with the nonprocedural protocol,
P/S
execute the INPUT instruction, and
read and discard the unnecessary data.
• Measure the noise.
• When connecting the multidrop, remove
the interlock so that data will not be
transmitted simultaneously by multiple
devices.
• Use DTR and DC control and perform
data communications so that the buffer
does not become full. (Perform RS ⋅ CS
control when the modem function is
SIO
used.)
• If the Reception data read request
signal was turned ON, execute reading
immediately.
• Recheck the CD(DCD) signal control of
the external device.
CHn
(Send while the CD(DCD) signal is ON.)
ERR.
• Set "Not check" and perform
communication.
• Transmit data after line connection
CHn
processing on the interface side that
ERR.
uses the modem function.
15 TROUBLESHOOTING
Protocol
Non- Bi-
Pre-
proce- direc-
MC
defined
dural tional
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