Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 76)

Asynchronous Link Protocols
Chapter 4
4-33
Figure 4.19
Message Transfer with ACK Destroyed
Not Full
OK
xxxx
xxxx
SINK MASTER LINK SLAVE SINK
11569
DLE ACK
SOURCE/ SOURCE/
DLE STX xxxx DLE ETX BCC DLE SOH STN
(Timeout)
DL ??? CK
DLE STX xxxx DLE ETX BCC DLE SOH STN
Figure 4.20
Poll with No Message Available
No Message
Not Full
SINK MASTER LINK SLAVE SINK
11570
DLE EOT
SOURCE/ SOURCE/
BCC DLE ENQ STN
Figure 4.21
Poll with Message Returned
xxxx
xxxx
OK
Not Full
SINK MASTER LINK SLAVE SINK
11571
DLE ACK
SOURCE/ SOURCE/
BCC DLE ENQ STN
DLE STX xx???xx DLE ETX BCC
BCC DLE ENQ STN
DLE STX xxxx DLE EXT BCC Same Message