Troubleshooting Using The Buffer Memory - Mitsubishi Electric MELSEC iQ-R Series User Manual

5.3

Troubleshooting Using the Buffer Memory

Check 'Error status' (Un\G29) to confirm the error status of the RJ71CN91.
Bit Error description
b0 System area
b1 Hardware error
b2 System area
b3 Bus off state, or the value of 'CAN
transmission error counter'
(Un\G35) becomes 256 or more.
b4 Flash ROM error
b5 Invalid save/restore configuration
request in Layer 2 message mode
b6 Buffer memory setting error
b7 System area
b8 Send/receive buffer overflow
b9 System area
b10 NMT error control failure
b11 to b13 System area
b14 CAN error active state/passive
state
b15 Layer 2 message slot specific error
Action

If this bit is not cleared when 'Module restart request' (Y2) is turned on or the RJ71CN91 is powered off
and on or reset, the RJ71CN91 hardware may be in failure.
Please consult your local Mitsubishi representative.

Check the following, and then power off and on or reset the RJ71CN91.
• Are terminating resistors connected to the both ends of the network?
• Is the baud rate the same at all nodes?
• Are all node IDs not duplicated?
• Are the CAN_H, CAN_L, and CAN_GND wires not disconnected?
• Is CAN_SHLD of the CAN bus cable grounded?
• Is CAN_SHLD of the CAN bus cable connected to all nodes?
• Is the CAN bus cable not short-circuited?
• Check that other nodes are running normally.
There is invalid data in the flash ROM.
If this bit is not cleared when 'Module restart request' (Y2) is turned on or the RJ71CN91 is powered off
and on or reset, the RJ71CN91 hardware may be in failure.
Please consult your local Mitsubishi representative.
Configuration save/factory default configuration restore operation was executed when the online mode
of Layer 2 message mode is active. Check the program and execute the configuration save/factory
default configuration restore operation when the RJ71CN91 was in the offline mode. For details on the
offline mode, refer to the following.
( Page 150 Layer 2 online mode status (X3), Layer 2 online mode request (Y3))
This bit turns on when a value out of the setting range is written to the buffer memory.
The buffer memory address where this error occurred is stored in 'Buffer memory setting error display'
(Un\G39). ( Page 162 Buffer memory setting error display (Un\G39))
Check 'Buffer memory setting error display' (Un\G39), and set the value in the setting range.

Extreme bus load caused the send buffer or receive buffer to overflow.
Decrease the bus load. Send buffer overflow may occur if data exchange is swiftly performed when the
baud rate is low.
When a large number of slaves are registered in "NMT slave assignment" for the master and then the
master and slaves are powered on, a receive buffer overflow may occur in a slave.

Check 'NMT error control status' (Un\G401 to Un\G527) and check the status of the node in which an
NMT error control error occurred. ( Page 168 NMT error control status (Un\G401 to Un\G527))

This bit turns on if the RJ71CN91 switches to the error passive state.
Check the following details.
• Are terminating resistors connected to the both ends of the network?
• Do all nodes have the same baud rate setting?
• Is any node ID duplicated?
• Is any CAN-ID duplicated?
• Is any communication cable disconnected?
• Are communication cables grounded properly?
• Is any communication cable short-circuited?
This error will be cleared when the value of 'CAN transmission error counter' (Un\G35) or 'CAN reception
error counter' (Un\G36) becomes 128 or less. ( Page 161 CAN transmission error counter (Un\G35),
Page 161 CAN reception error counter (Un\G36))
Refer to 'Message slot specific error code list' (Un\G5001 to Un\G5042) to check the error code of each
message slot. ( Page 176 Message slot specific error code list (Un\G5001 to Un\G5042))
5 TROUBLESHOOTING
5.3 Troubleshooting Using the Buffer Memory
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