Mitsubishi Melsec-L Series User Manual page 186

10 DATA COMMUNICATION USING THE NONPROCEDURAL PROTOCOL
(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 C24.
For this reason, the reception message may be missing data if 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 the data transmitted between the CPU module
and the external device 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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