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Chapter 7 Communication function
7-37
2) Sequence of command frame
A) Sequence of command request frame
ENQ
Station
No.
Command
Formatted
data
EOT
BCC
(PLC ACK response)
ACK
Station
No.
Command
Data
or null
ETX
BCC
(PLC NAK response)
NAK
Station
No.
Command
Error
code
ETX
BCC
B) Sequence of download/upload frame
ENQ
Station
No.
Start
command
data
EOT
BCC
(Down/upload start command)
ACK
Station
No.
Command
Data
or null
ETX
BCC
ENQ
Station
No.
Command
Formatted
data
EOT
BCC
(Down/upload command frame number H0001)
ACK
Station
No.
Command
Data
or null
ETX
BCC
ENQ
Station
No.
Command
Formatted
data
EOT
BCC
(Down/upload end command
Frame number H’FFFF)
ACK
Station
No.
Command
Data
or null
ETX
BCC