In conjunction with the TeleControl Server Basic software, the CP 1242-7 forms a telecontrol system on the basis of mobile wireless communication.

The external stations can be connected to the control center either continuously or as required. A higher-level control center system can exchange data with all stations via OPC. A service PC with STEP 7 can connect to any station via the control center for maintenance purposes.

GSM/GPRS communication with CP 1242-7 / Alerting by means of SMS

Operating modes

The CP 1242-7 can be used in two different operating modes:

TeleControl server

In this mode, communication with the control center and other telecontrol stations is handled via a central TeleControl server. The CP 1242-7 is connected to the TeleControl server. The TeleControl Server Basic software both forwards the data to the control station or other telecontrol stations and monitors it.

GPRS Direct

In this mode, the CP 1242-7 communicates direct with a control center or other telecontrol stations. In contrast to TeleControl mode, this requires no TeleControl server or additional software. This mode can be selected if there is a guarantee that the communication partners of the station can be reached using a unique address. To ensure this, special network operator services, frequently referred to as machine-to-machine (M2M), have to be used in normal cases.

Configuration

All the necessary information (provider data, access rights, operating modes) is configured with STEP 7. STEP 7 Basic V11 or higher is required for configuring the CP 1242-7.

The data can also be reconfigured during runtime. A special library function is available for this purpose.

Data buffering

Brief connection failures in the mobile wireless network are bridged by data buffering. When the connection has been restored, the buffered data is time-stamped and sent.

Time synchronization

The mechanism for time-of-day synchronization of the CP 1242-7 can be set dependent on the operating mode.

If a TeleControl server is used in the control center, the control center forwards the time of day to all substations. If TeleControl Server Basic is not used, synchronization can take place via an NTP server.

The CPU program can use this time to set the internal time-of-day for the station.

Function library

A function library for the following functions is available for the CP 1242-7:

• Data exchange: Send and receive functions enable data exchange with other stations or with the control center.
• Sending/receiving text messages
• Configuration: Reconfiguring can take place during operation with the help of a function block

Diagnostics/remote maintenance

An online connection to a remote S7-1200 station with CP 1242-7 can be established from STEP 7 via GPRS/Internet. After the connection has been established, all the familiar online functions for remote maintenance (download, diagnostics) are available.