Siemens SIMATIC S7-400 CP 440 - Sending Data with 3964(R); Figure 2-13 Data Traffic When Sending with the 3964(R) Procedure

Basic Principles of Serial Data Transmission
2.5 Data Transmission with the 3964(R) Procedure
Point-to-point connection CP 440 Installation and Parameter Assignment
Manual, 09/2007, A5E00057742-03
45
2.5.3 Sending Data with 3964(R)
Transmission Sequence
The figure below illustrates the transmission sequence when data is sent with the 3964(R)
procedure.
&3
67;
'/(
'/(
(7;
%&&
'/(
Ⴠ
Ⴠ
Ⴠ
Ⴠ
&RPPXQLFDWLRQ
SDUWQHU
VWE\WH
QGE\WH
VWGDWDE\WH
QGGDWDE\WH
QWKE\WHQWKGDWDE\WH
6WDUWFRGH+
3RVDFNQRZOHGJPHQW+
(QGFRGH+
(QGFRGH+
5RQO\
3RVDFNQRZOHGJPHQW+
&RQQHFWLRQ
VHWXS
8VHU
GDWD
&RQQHFWLRQ
FOHDUGRZQ
Figure 2-13 Data traffic when sending with the 3964(R) procedure
Establishing a Send Connection
To establish the connection, the 3964(R) procedure sends the control code STX. If the
communication partner responds with the DLE code before the acknowledgment delay time
expires, the procedure switches to send mode.
If the communication partner answers with NAK or with any other control code (except for
DLE or STX), or the acknowledgment delay time expires without a response, the procedure
repeats the connection setup. After the defined number of unsuccessful setup attempts, the
procedure aborts the connection setup and sends the NAK code to the communication
partner. The CP 440 reports the error to the SEND_440 function block (STATUS output
parameter).
该文档是极速PDF编辑器生成，
如果想去掉该提示,请访问并下载：
http://www.jisupdfeditor.com/
长沙工控帮教育科技有限公司
www.gkbpx.com