Mitsubishi QJ71MB91 User Manual page 344

11
TROUBLESHOOTING
Error code Error Name
7400
H
Framing error
(29696)
7401
H
Parity error
(29697)
7402
H
Overrun error
(29698)
7403
H
CS signal OFF
(29699)
7404
H
Buffer full error
(29700)
11
- 39 11.4 Error Codes
11.4.3 Error code list
Table11.16 Error code list (Continued)
Error definition
• 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.
• 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.
• 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.
• 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.
The OS buffer (the buffer provided
inside the module) is full.
Corrective Action
• 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.
• 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.
• 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.
• 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.
• 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.
Occurrence
1) 2) 3) 4) 5)
(Continued on next page)