Rockwell Automation 1775-KA PLC-3 Communication Adapter Module User Manual - Manual (Page 212)

Detailed Flowcharts
Appendix D
DĆ2
Figure D.2
Transmitter Routine for Full=-Duplex Protocol
XMIT
GETMSG
Get Message
from Network
Layer
Reset NAK
and Timeout
Counters
SENDM
Send Message
WTAK
Wait for ACK,
NAK or Timeout
SENDCTL
Send
DLE
ENQ
Received
DLE NAK
?
Received
DLE ACK
?
3*
NAKs
Received for this
Message
?
3*
Timeouts
for this
Message
?
SIGFAIL SIGOK SIGFAIL
Tell Net-
work
Layer of
Failure Tell Network
Layer Mesage
Was Sent Tell Net-
work
Layer of
Failure
10072–I
Yes
No
No
Yes
No
Yes
Yes
No
Internal Storage:
•
NAK Counter
•
Timeout Counter
Legend:
•
Default value
used by the mod-
ule