Design principle of a telecontrol system and plants with SIMATIC

Telecontrol involves the connection of distributed process stations to one or more central control systems. A telecontrol system can be subdivided into the following components

• Control center
• Substations
• Communication network

Various different public or private networks can be used for communication for the purposes of monitoring and control. The event-driven or cyclic exchange of the process data takes place via special telecontrol protocols such as SINAUT ST7, DNP3.

Substations

With SIMATIC, Siemens offers a wide range of components for the different application areas for establishing telecontrol substations – Remote Terminal Units (RTUs).

The hardware basis is a PLC, in each case supplemented for the telecontrol function with special hardware and software components, e.g. TIM communication modules. All the local functions supported by the respective PLC for the connection of I/O via bus systems, connection of HMI or sensors, etc., are also available without restriction in the RTU configuration.

The individual solutions differ in the:

• Performance class (number of required IO signals and controller performance)
• Support for the telecontrol protocols

The following table provides an overview of the different types of substations on offer with the essential features:

Classification of the different TeleControl substations (RTU types)

TIM communications modules

The hardware component for the telecontrol wireless station of a telecontrol substation is the TIM (Telecontrol Interface Module) communication module. It is used by the S7 CPU or control center PC for data exchange via the relevant telecontrol network, optionally with the SINAUT ST7, SINAUT ST1 or DNP3 protocol.

Different protocols cannot be combined in one communication network. However, communication networks with different protocols can always be combined in one project if they are connected to the main control center via separate interfaces.