Point-to-point connection CP 440 Installation and Parameter Assignment
Manual, 09/2007, A5E00057742-03
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Startup Characteristics and Operating Mode
Transitions of the CP 440
7
7.1
Operating Modes of the CP 440
The CP 440 has the operating modes STOP, parameter reassignment and RUN.
STOP
When the CP 440 is in STOP mode, no protocol driver is active and all send and receive
requests from the CPU are given a negative acknowledgment.
The CP 341 remains in STOP mode until the cause of the stop is removed (e.g. break,
invalid parameter).
Parameter reassignment
For parameter reassignment, the protocol driver is initialized.
Sending and receiving are not possible, and send and receive message frames stored in the
CP 440 are lost when the driver is restarted. Communication between the CP and the CPU
is started afresh (active message frames are aborted).
At the end of the parameter reassignment, the CP 440 is ready to send and receive.
RUN
The CP 440 processes the requests from the CPU. It provides the message frames received
by the communications partner to be fetched by the CPU.
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