Mitsubishi QJ71C24N User Manual page 176

6 DATA COMMUNICATION USING THE NON PROCEDURE PROTOCOL
MELSEC-Q
(4) Retry processing for data reception errors
The data when reception error occurred is discarded and only the data for the
normal reception is taken into the Q series C24. For this reason, the reception
message may be missing data when an error occurs. To assure the correct
transmission and reception of data it is recommended that a normal/error
response message is received and a response message reception timeout check
is conducted for data transmitted between the programmable controller CPU and
the external equipment and that measures be taken when an error message is
received or when an error timeout occurs, such as retransmitting the data
(transmission retry).
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