• Overview diagram:
  The complete sequential structure can be displayed.
• Single-page display:
  The sequential structure, the step enabling conditions and the step actions can be displayed together on a single page.
• Detail display:
  The actions, transitions (with the step enabling conditions) and interlocking and monitoring conditions associated with a step are displayed together.
• Flexible configuration of step sequences:
  With simultaneous and alternative branches, jumps within the sequence chains, step activation and deactivation, the user has a number of options for describing his task. In the same block, any number of parallel asynchronous step sequences can be configured.
• Scope of language:
  The scope of the language facilitates user programming of conditions and actions.
• Online functions:
  Display of active steps, status of Interlocking, monitoring and step enabling conditions, in addition to the actions executed.
• Performance:
  Good performance is achieved by selective processing of the steps. The processing time of a sequence of steps is independent of the number of steps.
• Link to a project-wide documentation system (DOCPRO)
• Memory requirements of the administration section can be adjusted as necessary;
  S7-GRAPH provides different settable compiler options for integrating the general management section of the sequencer block:
  • Option "can execute autonomously":
    The management section (approx. 5 KB) is included in every function block generated by S7-GRAPH. This is the solution for small applications with only one sequencer block.
  • Option with "standard FC”:
    The management section is swapped to a separate block that exists only once per project and is shared by all sequencer blocks. Depending on the type of this standard FC, the memory requirement can be 8 or 10 KB.
• System function "FC 73" (V5.1 or newer):
  The FC 73 supports reduced-memory solution of under 8 , which is especially interesting in smaller CPUs of the S7-300. The following restrictions are valid when using the FC 73:
  • The blocks created have no diagnostics capability.
  • The visualization of the blocks created is limited.
• Synchronization functionality:
  Operation sequences can be controlled and synchronized with the current state of the system/machine. In the event of program changes involving the download of the instance data block, the sequence is automatically reset to its initial state. The "Control sequence" function supports the setting and resetting of steps directly from the PG, so that the sequence can be reset to the plant status prior to the program change. Synchronization operations can also be performed directly from the PG. This will automatically cover all transitions and interlock conditions, and the respective steps will be flagged. The user can then simply select and activate the step(s).
• User-defined call interface:
  there are two possibilities for the call interface of the sequencer block:
  • Predefined parameter sets, optionally Mini, Standard and Maximum
  • User-defined parameters for flexible adaptation to the needs of the application
• Comprehensive diagnostic functions:
  Causes of malfunctions are found by indicating or reporting the faulty step. Moreover, incorporation into the SIMATIC diagnostics concept with SIMATIC ProTool/Pro and SIMATIC ProAgent supports the simple integration of operator panels and WinCC to display faults in plain text and show the cause signals (criteria analysis).
• Expandable printer functions (V5.1 or newer):
  • A page break always follows a "sequence step plus transition".
  • A page break is adjustable at the end of the sequencer/graph.
  • A specific comment can be entered for each graph.
• Improvement of the window structure (V5.1 or newer):
  The S7-GRAPH project window contains only the sequencer to be edited. All additional information that are needed for programming upon request can be revealed or hidden through the following windows:
  • Information on the interface of the block (block parameter and variables)
  • Addresses used (including status display for all data types)
  • Cross-references to other locations of the addresses in the program
  • Symbols used from the symbol table
• Simultaneous selection of several objects with usual Windows procedures (V5.1 or newer):
  • Lasso function (selection frame around the desired elements) with "cut, copy, paste" for simple and quick copying and deletion of sequence steps and transitions.
  • Elements that are not adjacent can be selected via the "Ctrl" key.
  • With parallel structures, individual branches or graphs can be selected with the lasso function and deleted.

Mode of operation

Sequence chains display the individual steps of a process and the transitions to the next steps as rectangles and lines (illustration). Within the steps, actions can be initiated by so-called "qualifiers" (e.g., time-delayed or conditional execution). If, for example, the operating sequence describes a drilling process, the "lowering of the drill" will be a step and the "activation of the motor" will be an action.

The transitions describe the conditions under which a transition to the next step should occur. In the example of the "drilling process", the criterion for step-enabling the operation sequence would be fulfilled if the condition "lower final position reached" is met.

In addition, interlocking and monitoring conditions can be defined for every step.
An interlock can be used to prevent the execution of actions. Monitoring conditions enable the recognition of operational faults. All conditions (transitions, interlocking or monitoring) can be programmed either in LAD or CSF.