Mitsubishi Electric MELSEC iQ-R Series User Manual page 85

Master function own node area
This area is used to store the communication status and error information of the master function.
■Master function communication status (Un\G432)
The communication status of the master function is stored.
• Upper byte
The I/O communication status of the master function is stored.
The following table lists the values to be stored depending on the communication status.
Value Name
00H OFFLINE
40H STOP
C0H OPERATE
When 'Auto communication start setting' (Un\G1585) is set to "No Start", the status automatically switches to STOP (40H)
from OFFLINE (00H) at power-on. Turning on 'I/O communication request' (Y11) switches the status to OPERATE (C0H).
When 'Auto communication start setting' (Un\G1585) is set to "Start", the status automatically switches to OPERATE (C0H)
from OFFLINE (00H) at power-on.
When a reset message is received from the network, the status automatically returns to OFFLINE (00H) and switches to
OPERATE (C0H).
• Lower byte
The network communication status is stored.
Each bit turns on and off as follows depending on the communication status.
• b0: There is a node with a communication error.
• b1: This bit is always off.
• b2: A parameter error occurs.
• b3: The communication cannot be performed due to a serious problem in the network.
• b4 to b7: This bit is always off.
■Master function error information (Un\G433)
The communication error code compatible with the QJ71DN91 occurred in the master function is stored.
As the communication error codes are the same as those of the QJ71DN91, refer to the following.
 DeviceNet Master-Slave Module User's Manual
■Bus error counter (Un\G434)
The number of CAN chip (DeviceNet communication chip) illegal frame counts exceeding 96 times is stored.
If this value becomes lager, it indicates that the communication is unstable.
■Bus off counter (Un\G435)
The number of the RJ71DN91 transitions to the bus off status is stored.
If this value becomes lager, it indicates that the communication is unstable.
■Master function communication error information (Un\G1152)
The communication error code which occurs on the own node in the master function mode is stored. ( Page 59 Error code
for module diagnostics (own node error))
The node address (MAC ID) of the node where an error has occurred is stored in the lower byte of the communication error
code.
• FEH, FFH (254, 255): Own node (RJ71DN91 master node)
• 00H to 3FH (0 to 63): Node address (MAC ID) of the node where an error has occurred
If an error occurs in multiple nodes, the error occurred in the node with the smallest node address (MAC ID) is
stored.
For how to notify error occurrence and how to clear this area, refer to the following.
Page 67 For master function error (X03), (Y13)
Operation
Initializing, bus off, network power-off
I/O communication stop
I/O communicating
Appendix 3 Buffer Memory
A
APPX
83