Communication Event Log Timing And Storage Format - Mitsubishi FX3U Series User Manual

FX Series Programmable Controllers
3U
User's Manual - MODBUS Serial Communication Edition
9.5.2

Communication event log timing and storage format

1) When receiving a request message:
The slave (FX-Series MODBUS Communication ADP) stores this kind of event to the communications
event log before executing the processing of the request message.
For the relevant communications event, "1" is stored.
b7 b6 b5 b4 b3 b2 b1 b0
1/0 1/0 1/0 0
1
2) When sending a response message:
The slave (FX-Series MODBUS Communication ADP) stores this kind of event to the communications
event log after sending the response message.
For the relevant communications event, "1" is stored.
b7 b6 b5 b4 b3 b2 b1 b0
0 1 1/0 0
Note
As the FX-Series MODBUS Communication ADP will never be in a state that details exception code 05H to
07H. Therefore the bits 2, 3 & 4 will always read "0" when using a FX-Series MODBUS Communication ADP.
3) When switching to the listen only mode:
The slave (FX-Series MODBUS Communication ADP) stores this kind of event to the communications
event log when switching to the listen only mode.
04H is stored to the communications event log.
0 1/0 0
Unused (Fixed to 0)
Communication error
Unused (Fixed to 0)
Bus character overrun error
In listen only mode
Broadcast message reception
Fixed to 1
1/0
0 0 1/0
Read exception sent - exception code 01H to 03H
Slave abort exception sent - exception code 04H
Slave busy exception send - exception code 05H or
06H, (when using FX
Slave NAK (Negative acknowledge) exception sent -
exception code 07H, (when using FX
fixed to 0)
Write timeout error occur (when using FX
unsupported - fixed to 0)
Currently in listen only mode
Slave send event - fixed to 1
Slave send event - fixed to 0
b7 b6 b5 b4 b3 b2 b1 b0
0 0 0
0
slave unsupported - fixed to 0)
3U
3U
0 1 0 0
9 Slave Specification
9.5 Communication Event log
slave unsupported -
slave
3U
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