Siemens 6GK7242-7KX30-0XE0 ユーザーズマニュアル

Notes on operation and configuration

4.2 Connection modes and connection establishment

CP 1242-7

Operating Instructions, 03/2012, C79000-G8976-C247-03

● GPRS direct

This mode of the CP is used for direct communication between remote stations via the

GSM network. No telecontrol server is necessary.
To allow network nodes in public wireless networks to be directly accessible, these need

to be addressed using a fixed address. Here, SIM cards with a fixed IP address are used

that allow the stations to address each other directly.
The possible communications services and security functions (for example VPN) depend

on what is offered by the network provider.
Possible communications partners of the GPRS station with a CP 1242-7 in "GPRS

direct" mode are:
– A subscriber that can be reached by the CP via an IP address (for example S7-1200

with CP 1242-7)

– An engineering station (for TeleService)

4.2

Connection modes and connection establishment

Note
Connection interrupted by GSM network provider
When using the GPRS service, remember that existing connections can be interrupted by

GSM network providers for maintenance purposes.

Connection modes

● "GPRS direct" mode

There are no different connection modes in the "GPRS direct" mode.

● "Telecontrol" mode

The CP can be configured for the following connection modes.
– "Permanent" connection mode

There is a permanent TCP connection to the telecontrol server. Following connection

establishment, there is a permanent TCP connection to the telecontrol server even if

data is not transferred permanently.

– "Temporary" connection mode

A connection is only established to the telecontrol server when required.

If a TCP connection is established, process data is sent as soon as the telecontrol

instructions are called on the CPU.