Mitsubishi Electric MELSEC-L Series - Page 191

189
CHAPTER 14 OTHER FUNCTIONS
14
14.4 Remote Password 14.4.5 Precautions
(7) When the unlock process or lock process fails
If the remote password unlock/lock process fails, check the remote password of the CPU module then perform
the unlock/lock process again.
(a) E71 operation in case of a process failure
If the number of process failures exceeds the notification accumulated count
*1
set in the buffer memory area,
the E71 performs the following operations.
• The E71 turns on the COM.ERR. LED.
• The E71 stores C200
H
in the error code and end code storage area in the buffer memory area, Error log
area (address: E3
H
to 174
H
).
*1 This is the number of times stored in Remote password mismatch notification accumulated count designation (address:
5070
H
and 5071
H
) by the CPU module (using an instruction such as the TO instruction) when the E71 starts up.
In the above case, identify the connection where the unlock/lock process has failed using the following buffer
memory areas.
• Accumulated count of unlock process abnormal end (address of Connection No.1: 5073
H
)
• Accumulated count of lock process abnormal end (address of Connection No.1: 5075
H
)
(b) Corrective action against a process failure
Take the following actions if required.
• Close the connection with the connected device.
• Write "0" in the buffer memory areas, Accumulated count of unlock process abnormal end (address: 20595
(5073
H
) and Accumulated count of lock process abnormal end (address: 20597 (5075
H
)). If this action is
not taken, the process (a) above will be performed each time a process failure occurs exceeding the
notification accumulated count.
• If the number of unlock/lock process failures for the connection to the connected device is greater than the
above accumulated notification count, the possible cause is unauthorized access from the connected
device. Disable the connection using the buffer memory area, System port use prohibited designation area
(address: 5008
H
) (After this, the unlock process cannot be performed for the connection until "Use
allowed" is set.)
• Inform the system manager that the number of unlock/lock process failures is greater than the
accumulated notification count, and take corrective actions.
● For the method to turn off the COM.ERR. LED, refer to the method using the Ethernet diagnostics. ( Page 303,
Section 16.10)
● The accumulated counts of unlock/lock process abnormal end for Connection Nos.1 to 16 stored in the buffer memory
can be cleared.
• Accumulated count of unlock process abnormal end (address of Connection No.1: 5073
H
)
• Accumulated count of lock process abnormal end (address of Connection No.1: 5075
H
)