Mitsubishi QJ71MB91 - Page 344

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11.4 Error Codes
11.4.3 Error code list
11
TROUBLESHOOTING
Table11.16 Error code list (Continued)
(Continued on next page)
Error code Error Name Error definition Corrective Action
Occurrence
1) 2) 3) 4) 5)
7400
H
(29696)
Framing error
• The stop bit position is incorrect.
• The stop bit setting is incorrect.
• The transmission setting is
inconsistent.
• Turning ON/OFF the equipment
produced a disturbance on the line.
• Electric noise was generated on the
line.
• There are two or more masters.
• Data transmission occurred
simultaneously.
• Match the stop bit setting on the
QJ71MB91 with that on the target
device.
• Match the transmission setting on
the QJ71MB91 with that on the
target device.
• Take preventive measures against
noise.
• Use one master in the system.
• Adjust the transmission timing to
prevent simultaneous data
transmission.
7401
H
(29697)
Parity error
• The parity bit check ended in error.
• The parity bit setting is incorrect.
• The transmission setting is
inconsistent.
• There is fluctuation on the line
caused by a device turning on and
off.
• Electric noise was generated on the
line.
• There are two or more masters.
• Data transmission occurred
simultaneously.
• Match the parity bit setting on the
QJ71MB91 with that on the target
device.
• Match the transmission setting on
the QJ71MB91 with that on the
target device.
• Take preventive measures against
noise.
• Use one master in the system.
• Adjust the transmission timing to
prevent simultaneous data
transmission.
7402
H
(29698)
Overrun error
• The next data was received before
completion of the current reception
processing.
• The transmission speed exceeds the
limit of the QJ71MB91.
• An instantaneous power failure
occurred.
• Check if the transmission speed is
within the limit of the QJ71MB91.
• Check if no instantaneous power
failure is occurring on the station.
(This can be checked with special
register SD1005 of the
programmable controller CPU.)
Remove the cause of the
instantaneous power failure if it is
occurring.
• Reduce the transmission speed.
7403
H
(29699)
CS signal OFF
• The CS signal was OFF at the time
of request or response message
transmission, resulting in failure of
the transmission.
• A cable is disconnected.
• A cable is faulty.
• Confirm that the cables are not
disconnected.
• Check the cable connection and
correct the wiring so that the CS
signal on the CH1 (RS-232) side will
be always ON.
7404
H
(29700)
Buffer full error
The OS buffer (the buffer provided
inside the module) is full.
• If the programmable controller CPU
has any problem, remove it.
• Check if the transmission speed is
within the limit of the QJ71MB91.
• Check if no instantaneous power
failure is occurring on the station.
(This can be checked with special
register SD1005 of the
programmable controller CPU.)
Remove the cause of the
instantaneous power failure if it is
occurring.
• Reduce the transmission speed.
• Reduce the frequency of requests
from the target device.