Mitsubishi QJ71MB91, User Manual

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- 49 4.13 Get Communications Event Log (FC: 12)
4
MODBUS(R) STANDARD FUNCTIONS
2) When sending a response message
The slave (QJ71MB91) stores the communications event log after sending the
response message.
For the relevant communications event, "1" is stored.
* 1 While the occurrence of busy status (exception code 05
H
to 07
H
) is stored for the MODBUS
protocol, "0" is stored for the QJ71MB01 because this kind of events does not occur in it.
3) When switching to the listen only mode
The slave (QJ71MB91) stores the communications event log when switching
to the listen only mode.
04
H
is stored to the communications event log.
4) When processing restart communications option
The slave (QJ71MB91) stores the communications event log when processing
the restart communications option.
00
H
is stored to the communications event log.
(b) Clearing the communications event log
The communications event can be cleared by either of the following:
Clear setting of the communications event log with the restart communications
option ( Section 4.11.2)
Power OFF ON, or programmable controller CPU reset
Figure 4.79 Communications event at response message transmission
Figure 4.80 Communications event when switching to listen only mode
Figure 4.81 Communications event when processing restart communications option
b0 b1 b2 b3 b4 b5 b6 b7
0 0 0 1 0 0 1/0 1/0
Message error (Exception code 01
H
to 03
H
)
Processing interruption (Exception code 04
H
)
Unused (Fixed to 0) * 1
Fixed to 1
Unused(Fixed to "0")
b0 b1 b2 b3 b4 b5 b6 b7
0 0 1 0 0 0 0 0
b0 b1 b2 b3 b4 b5 b6 b7
0 0 0 0 0 0 0 0