Startup Characteristics and Operating Mode Transitions of the CP 440
7.3 Behavior of the CP 440 on Operating Mode Transitions of the CPU
Point-to-point connection CP 440 Installation and Parameter Assignment
Manual, 09/2007, A5E00057742-03
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7.3
Behavior of the CP 440 on Operating Mode Transitions of the CPU
Once the CP 440 has been started up, all the data is exchanged between the CPU and the
CP 440 via the function blocks.
CPU STOP
In CPU STOP mode, communication via the S7 backplane bus is not possible. Any active
CP CPU data transmission, including both send and receive message frames, is aborted and
the connection is reestablished.
Data traffic at the interface of the CP 440 is continued with the ASCII driver in the case of
parameter assignment without flow control. In other words, the current send request is
completed. Receiving the data depends on the setting of the basic parameter "Reaction to
CPU Stop".
CPU STARTUP
On start-up, the CP sends the parameters created with the CP 440: Point-to-Point
Communication, Parameter Assignment programming interface. The CP 440 only parameter
reassignment if the parameters have changed.
CPU RUN
When the CPU is in RUN mode, sending and receiving are unrestricted. In the first FB cycles
following the CPU restart, the CP 440 and the corresponding FBs are synchronized. No new
FB is executed until this is finished.
Points to Note when Sending Message Frames
Message frames can be sent only when the CPU status is RUN.
If the CPU goes into STOP during data transmission from the CPU " CP, the SEND_440 FB
reports after restart that the current program has been interrupted and the job has been
terminated due to BREAK/restart/reset.
Note
The CP 440 does not send data to the communications partner until it has received all data
from the CPU.
See also
Basic Parameters of the CP 440 (Page 68)
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