Mitsubishi Electric QJ71DN91 User Manual page 52

3 SPECIFICATIONS
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(2) Error Information for Master Function (address: 01B1
A code for a communication error occurred in the master function is stored.
For error notification and a clearing method of this area, refer to Section 3.3.2 (4).
(a) High byte
An error code is stored. (Refer to Section 9.2.1.)
(b) Low byte
The number of the node (MAC ID), where an error occurred, is stored.
FE , FF (254, 255): Own node (QJ71DN91)
H H
0 to 3F (0 to 63): Node No. (MAC ID) of the slave node where an error
H H
occurred.
POINT
If errors occur at multiple nodes, the error information of the node with the smallest
node No. (MAC ID) is stored.
(3) Bus Error Counter (address: 01B2
The number of times that the illegal frame count of the CAN chip (DeviceNet's
communication chip) exceeded 96 is stored.
An increase of this value means that communications are unreliable.
(4) Bus Off Counter (address: 01B3
The number of times that the QJ71DN91 was placed in the bus off status is
stored.
An increase of this value means that communications are unreliable.
(5) Operation Setting Area for Bus Off Error (address: 0632
Set whether or not to reset the QJ71DN91's CAN chip (communication chip) to
resume the communication in the event of a bus off error,
Setting "1" in this area enables communication resumption without resetting the
CPU module.
This setting must be done before I/O communication (before setting I/O
Communication Request (Y11) to ON).
Even if "1" is set in this area after occurrence of a bus off error, the CAN chip is
not reset.
0: Stop communication without resetting the CAN chip (Default)
1: Resume communication by resetting the CAN chip
*: When any value other than 0 and 1 is set, the CAN chip is not reset.
(a) Confirming a bus off error
A bus off error can be confirmed by a LED and relevant values in the buffer
memory.
1) LED
The NS LED on the QJ71DN91 turns ON red.
2) Buffer memory
How many times the error occurred is stored in Bus Error Counter
(address: 01B2
/434)
H
/435)
H
) and Bus Off Counter (address: 01B3
H
MELSEC-Q
/433)
H
/1586)
H
).
H
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