Startup Characteristics And Operating Mode Transitions Of The Cp 440; Operating Modes Of The Cp 440; Startup Characteristics Of The Cp 440 - Siemens SIMATIC S7-400 Equipment Manual

Startup Characteristics and Operating Mode
Transitions of the CP 440
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.
7.2

Startup Characteristics of the CP 440

Startup Phases of the CP 440
The CP 440 start-up is divided into two phases:
• Initialization (CP 440 in POWER ON mode)
• Parameter assignment
Initialization
As soon as the CP 440 is energized, all module components are initialized.
Point-to-point connection CP 440 Installation and Parameter Assignment
Equipment Manual, 03/2022, A5E00057742-AE
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