Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 09/2008, A5E02191071-01
59
2.5.3
Quasi-Full-Duplex Operation
Quasi-full-duplex mode
Quasi full-duplex mode means: The partners can send command and response message
frames at any time as long as the other partner is not sending. The maximum nesting depth
for command and response message frames is "1". The next command message frame,
therefore, cannot be processed until the previous one has been answered with a response
message frame.
It is possible under certain circumstances - if both partners want to send - to transmit a
SEND message frame from the partner before the response message frame. For example, if
a SEND message frame from the partner was entered in the output buffer of the CP 341
before the response message frame.
In the following figure the continuation response message frame to the first SEND message
frame is not sent until after the partner's SEND message frame.
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Figure 2-17 Quasi-full-duplex mode
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