Notes on operation
4.1 Connection modes and connection establishment
CP 1242-7
34
Operating Instructions, 09/2011, C79000-G8976-C247-02
A connection is always established by the CP. If a connection established by the CP is
interrupted, the CP automatically attempts to re-establish the connection.
Triggering connection establishment for permanent stations ("Telecontrol" mode)
In the "Telecontrol" mode, the permanent connection to the telecontrol server is established
when the station starts up. If the connection is interrupted, the CP attempts to re-establish
the connection at 15 minute intervals. Connection establishment to the main or substitute
server can, however, also be initiated by a wake-up SMS (see below).
Note
Cyclic data exchange with the telecontrol server
The special settings for cyclic data exchange initiated by a telecontrol server are described in
the section Data management and cyclic data exchange (Page 38).
Triggering connection establishment for temporary stations ("Telecontrol" mode)
With "temporary" stations, connection establishment can be triggered by the following
events:
●
Event on the local CPU that needs to be evaluated by the program.
In terms of the program, two situations need to be distinguished:
–
Events that lead to a single connection establishment (for example alarms or
commands from the operator).
–
Expiry of an interval that leads to cyclic connection establishment (for example once
daily for data transmission)
●
Request by a communications partner (OPC client or S7 station)
The request from the communications partner leads to the connection being established.
●
Request for TeleService by an engineering station
The request switched by the telecontrol server or TeleService gateway does not need to
be evaluated in the program.
●
Wake-up SMS of the telecontrol server
The wake-up SMS can be triggered spontaneously on the telecontrol server. It is also
possible to configure cyclic sending on the telecontrol server.
●
Telephone wake-up call
The wake-up call can be sent from a telephone that has a phone number authorized in
the STEP 7 project. The telephone must support the CLIP function (transfer of its own call
number).
The connection establishment with the (main) telecontrol server is triggered.
