SIEMENS Basic software STEP 7 Lite


  • Programming software for creating stand-alone systems with SIMATIC S7-300, SIMATIC C7, ET 200S and ET 200X
  • Operation is simple and intuitive
  • Projects created with STEP 7/STEP 7 Professional can still be used


STEP 7 Lite is the new, extremely simple and intuitive programming software for implementing non-networked solutions with SIMATIC S7-300, SIMATIC C7, ET 200S (IM 151/CPU and IM 151/CPU FO) and ET 200X (BM 147/CPU). STEP 7 Lite has been structured such that it is extremely easy to learn within a short time and provides users with optimum support in every phase of a project. Projects produced using STEP 7 Lite can be used further with STEP 7/STEP 7 Professional.

STEP 7 Lite includes user-friendly functions for all phases of an automation project:

  • Hardware configuration and parameterization.
  • Programming.
  • Testing, commissioning and service.
  • Documentation.
  • Operating/diagnostics functions.

All functions are supported by a powerful, multi-stage online help system at all times.

Communication between automation systems and the use of CP and FM modules are not supported by STEP 7 Lite. It is necessary to use STEP 7 or STEP 7 Professional in such cases.

Optional packages are available for STEP 7 Lite:

  • S7-PLCSIM:
    The S7-PLCSIM simulation software permits functional testing of the created SIMATIC S7 user blocks on a PG/PC, without the target hardware having to be available. Thus the detection and elimination of programming errors are transferred to an early phase of the development. This means:

    • Faster initial commissioning at lower cost.
    • Increase in program quality.
  • TeleService:
    TeleService allows remote maintenance of SIMATIC S7/C7 automation systems using a PG/PC over a hardwired or radio network. Users can apply the known functionalities of STEP 7 and the engineering tools, comparable with a local MPI connection. TeleService increases the effective availability of plants and machines. Access with TeleService means that technical services (e.g. maintenance, updating or fault analysis) can be carried out cost-effectively from a central service point.

Other SIMATIC software packages, e.g. engineering tools, cannot be used with STEP 7 Lite.

STEP 7 Lite is available as a software package for PC installation. A PC adapter, CP 5511, CP 5512 or CP 5611 is required for use with a PC.

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STEP 7 LITE blocks

In the case of STEP 7 LITE, all the user programs as well as the data that they use are stored in blocks. The possibility of calling other blocks within one block, as though they were subroutines, enables the structuring of the user program. This increases considerably the organizational clarity, the comprehensibility and the ease of maintenance of PLC programs. The following types of blocks are available:

  • Data handling blocks (DHBs) control program execution.
    • OBs are divided into classes (e.g., time-driven, alarm-driven), independently of the triggering event. These classes have levels of priority. Depending on their respective priority levels, one can interrupt another.
    • When an OB is started, detailed information about the event initiating the start is provided. This information can be evaluated in the user-written program.
  • Function blocks (FBs) contain the actual user program.
    • Function blocks can be supplied with different data each time they are called (the so-called instance). These data, as well as internal variables (e.g., for intermediate values) and results are stored in the assigned instance-data block and are automatically managed by the system.
  • When an FB/SFB is called, instance data blocks (instance DBs) are assigned to the block. They are automatically generated when these blocks are compiled.
    • The user can access these instance data (symbolically as well, of course) from any point in his user program or from an HMI system.
  • Functions (FCs) contain program routines for frequently used functions.
    • Each function has a fixed function value (as an expansion to the IEC standard, several output parameters are possible). The output parameters must be processed immediately after the call. Thus functions do not require any instance-data blocks.
  • Data blocks (DBs) are data areas for storing user data.
    • In addition to the data that is assigned in each case to a function block (instance data), global data can be defined and can be used by any of the software modules (e.g., for recipes).
    • An elementary or structured data type can be assigned to the components of a data block. Elementary data types are, for example, BOOL, REAL or INTEGER. Structured data types (fields and structures) are built up from elementary data types (e.g., a recipe). The data of a dat block can be symbolically addressed. This facilitates the programming and the readability of the program.
  • System function blocks (SFBs); function blocks (see above) that are integrated in the CPU’s operating system, e.g., SEND, RECEIVE, controller. The variables of the SFBs are also filed in IDBs.
  • System functions (SFCs); functions (see above) that are integrated in the CPU’s operating system, e.g., time functions, block transfer.
  • System data blocks (SDBs) are data for the CPU’s operating system containing the system settings, e.g., module parameters.

Project overview

The project overview manages all the data belonging to an automation project – regardless of the target system (SIMATIC S7, SIMATIC C7 or ET 200S/X) on which they are located.

Symbol Editor

With the tool Symbol Editor all global variables (in contrast to the local formal parameters that are declared when the blocks are programmed) are managed. The following functions are available:

  • Definition of symbolic designations and comments for the process signals (inputs/outputs), flags and blocks
  • Sorting functions
  • Data exchange with other Windows programs.

The symbol charts that are generated when this tool is used are available to all applications. Changes to a symbol parameter are therefore automatically recognized by all tools.


STEP 7 Lite provides various tools for implementing the user’s automation task:

  • Project overview:
    For clear and rapid access to all tools and data for SIMATIC S7 and SIMATIC C7.
  • Symbol editor:
    For defining symbolic designations, data types, and comments of global tags.
  • Hardware configuring with pixel graphics:
    For configuration of the automation system and for parameterization of all settable modules.
  • Information functions:
    For a fast overview of CPU data and the causes of trouble during execution of a user program.

For developing the user program, STEP 7 Lite offers the following well-proven and standardized PLC programming languages:

  • Statement List (STL)
  • Ladder diagram (LAD)
  • Function Block Diagram (FBD)

But no other programming languages or technology-oriented configuration tools can be used.

Components for connection of the PC to MPI and PROFIBUS

The components described below, used together with STEP 7 support the connection of programming devices and PCs or notebooks to PROFIBUS and the multipoint interface (MPI) of SIMATIC S7.

PC adapter USB

  • For connecting a PC to the SIMATIC S7 automation system via the USB interface
  • Can be connected to USB 1.1 and 2.0 interfaces
  • Can be used with SIMATIC S7-200, S7-300, S7-400 and C7
  • Supports routing
  • Automatic transmission rate and profile search
  • Significantly enhanced performance (up to 3 times faster than the PC adapter via RS 232)
  • With firmware that can be upgraded in the future, e.g., for function expansion or error rectification
  • Can be used with Windows 2000, Windows XP Home and Windows XP Professional
  • Scope of supply:
    • PC adapter USB
    • CD “SIMATIC Software PC Adapter USB” with software and documentation
    • USB cable, 5 m
    • MPI cable, 0.3 m

CP 5511

  • For PGs/PCs/notebooks with PCMCIA slot
  • PCMCIA card type II (16-bit)
  • Incl. adapter with 9-pin Sub-D socket for connection to PROFIBUS

CP 5512

  • For PGs/PCs/notebooks with PCMCIA slot
  • PCMCIA card type II (Cardbus 32-bit)
  • Incl. adapter with 9-pin Sub-D socket for connection to PROFIBUS

CP 5611 or CP 5611-MPI

  • For PGs/PCs with a PCI slot
  • Short PCI card (32-bit)
  • CP 5611 MPI including MPI cable
Components for connecting the PC to Industrial Ethernet

The PC modules described below support, in combination with the software STEP 7 and SOFTNET-PG (V6.0 and higher) for Industrial Ethernet, the connection of programming devices and AT-compatible PCs or notebooks to Industrial Ethernet.

CP 1512

  • For PGs/PCs/notebooks with PCMCIA slot
  • PCMCIA card type II (Cardbus 32-bit); 10/100 Mbps
  • Incl. adapter with RJ45 socket for connection to Industrial Ethernet.

CP 1612

  • For PGs/PCs with a PCI slot
  • Short PCI card (32-bit); 10/100 Mbps
  • With RJ45 socket for connection to Industrial Ethernet

For technical details concerning versions and supported operating systems, please refer to the catalog data for the respective products.

Technical specifications

Article number


Product type designation

PC adapter USB A2

Transmission rate

Transfer rate

  • ● at the 1st interface acc. to PROFIBUS

9.6 kbit/s … 12 Mbit/s


Number of electrical connections

  • ● at the 1st interface acc. to PROFIBUS


Number of interfaces acc. to USB


Type of electrical connection

  • ● at the 1st interface acc. to PROFIBUS

9-pin Sub-D socket (RS 485)

  • ● of the USB interface

Standard-B socket

Standard for interfaces USB 2.0


Supply voltage, current consumption, power loss

Type of voltage of the supply voltage


Type of voltage supply optional external supply


Supply voltage

  • ● from USB

5 V

  • ● Note

Supply direct from USB

Relative symmetrical tolerance at DC

  • ● at 5 V

5 %

Consumed current

  • ● from USB

0.2 A

Power loss [W]

1 W

Permitted ambient conditions

Ambient temperature

  • ● during operation

0 … 60 °C

  • ● during storage

-40 … +70 °C

  • ● during transport

-40 … +70 °C

Relative humidity at 30 °C during operation maximum

95 %

Protection class IP


Design, dimensions and weight

Module format

USB V2.0 adapter


58 mm


26 mm


105 mm

Net weight

365 g

Mounting type 35 mm DIN rail mounting


Number of plug-in cards of same design plug-in per PC station


Number of units Note

Performance data

Product functions Diagnosis

Product function

  • ● Port diagnostics


Standards, specifications, approvals


  • ● for EMC


  • ● for safety from CSA and UL

cULus, UL 60950-1, CSA22.2

  • ● for emitted interference

EN 61000-6-3, EN 61000-6-4

  • ● for interference immunity

EN 61000-6-1, EN 61000-6-2

Certificate of suitability

  • ● CE marking


  • ● C-Tick