Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
PtP coupling and configuration of CP 340
40
Manual, 04/2011, A5E00369892-03
Receiving with the 3964(R) procedure
The figure below illustrates receiving with the 3964(R) procedure.
Receiving with procedure 3964(R) (part 1)
Character not equal to STX or faulty
character
Send request
NAK or BREAK
Waiting for character
time delay
Send NAK
Initialization conflict, own
priority low
STX received after
expected repeat
Yes
Add waiting time to free
receiving buffer
No
Has waiting time of 400
ms expired ?
No
Send NAK
Send DLE
Is receiving buffer
free ?
Waiting 50 ms
G
1
S T X
G
2
3
4
W = 0
W + 1
Figure 2-9
Flow diagram of receiving with the 3964(R) procedure (part 1)
R: Counter for retries
D: Default state
Summary of Contents for SIMATIC CP 340
Page 6: ...Preface PtP coupling and configuration of CP 340 6 Manual 04 2011 A5E00369892 03 ...
Page 10: ...Table of contents PtP coupling and configuration of CP 340 10 Manual 04 2011 A5E00369892 03 ...
Page 200: ...Index PtP coupling and configuration of CP 340 200 Manual 04 2011 A5E00369892 03 ...