Mitsubishi Electric MELSEC iQ-R Series User Manual page 448

Data communication status (transmission sequence status) reading method
The following shows how to read the current data communication status using the MC protocol stored in the buffer memory.
This read processing is for checking the data communication status using the MC protocol when a transmission problem
occurs.
■Transmission sequence status (Un\G597/613)
The status of data communication using the MC protocol is stored as a numeric value as shown below.
Buffer memory address
The following shows the correspondence between the numerical values in the transmission sequence status storage area and
the data communication status.
Request from a target device
E
N
Q
Target device
HL
C24
Stored
0 1
value
• Remarks
When the target interface is not set to use the MC protocol, '0' is stored in the 'Transmission sequence status' (Un\G597/613).
27 TROUBLESHOOTING
446
27.1 Checking Module Status
b15
to
Un\G597
0 to
0
to
Un\G613
Message wait
Request
to CPU
Response
from
CPU
3 4
2
Values 7 to 9 are stored when "mode
switching" or "initialization
of transmission sequence" is performed.
b6
(Information on the CH1 side)
9
9
(Information on the CH2 side)
ACK
or
NAK
"6" "1"..."6" is repeated afterward.
5 6