Message transfer with nak on reply, The reply is sent again and is successful – Rockwell Automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command User Manual
Page 69
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4–15
Using Full-duplex Protocol to Send and Receive Messages
Publication 1770Ć6.5.16 - October 1996
Message Transfer with NAK on Reply
In this transfer:
•
the message is successfully transmitted on the network
•
the reply is corrupted and the transmitter responds with a DLE
NAK
•
the reply is sent again and is successful
xxxx
not full
OK
OK
xxxx
xxxx
DLE STX xxxx DLE ETX BCC/CRC
DLE STX x??x DLE ETX BCC/CRC
DLE ACK
Source
Transmitter
Link
Receiver
Sink
command
reply
(sometime later ...)
DLE ACK
not full
DLE NAK
DLE STX xxxx DLE ETX BCC/CRC
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