Siemens Simatic S7-300 CP 341 - Figure 2-21 Flow Diagram for Receiving with End Criterion Expiration of Character Delay Time

Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 09/2008, A5E02191071-01 65
End criterion "Expiration of character delay time"
When data is received, the end of the message frame is recognized when the character
delay time expires. The received data is accepted by the CPU.
In this case the character delay time must be set such that it is certain to expire between two
consecutive message frames. But it should be so long that the end of the message frame is
falsely identified in the case of a send pause of the link within a message frame.
The figure below illustrates a receive operation with the end criterion "Expiration of character
delay time".
:DLWLQJIRU
FKDUDFWHU
&KDUDFWHU
DUULYHG

&KDUDFWHUUHFHLYHG
ZLWKFKDUDFWHU
GHOD\WLPH
PRQLWRULQJ
(QWHUPHVVDJHIUDPH
LQUHFHLYHEXIIHU
PD[0)VRU
E\WHV
(QWHUHUURULQ
67$786RXWSXWRI
WKH)%
:DLWLQJIRUFKDUDFWHU
GHOD\WLPH5HFHLYHG
FKDUDFWHUVGLVFDUGHG
(UURUZKHQUHFHLYLQJQRWD
FKDUDFWHUGHOD\WLPHHUURU
0HVVDJHIUDPHEXIIHUHG
(QGFULWHULRQIRUPHVVDJHIUDPHLGHQWLILHGHUURUHQWU\IROORZV
0HVVDJHIUDPH
FRPSOHWHFKDUDFWHU
GHOD\WLPHH[SLUHG
Figure 2-21 Flow diagram for receiving with end criterion "Expiration of character delay time"
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