Configuration of function block diagrams
The function block diagram (FBD) is a graphical programming language for performing open-loop and closed-loop control functions.
An FBD program is an arrangement of elements of the function block diagram, in which functions, function modules, and program inputs and outputs are logically combined via signal flow lines. The signal processing needed for controlling a process is obtained by means of the FBD programs. The CAD functional capabilities permit easy positioning and connection of functions and function modules in the plan.
Corresponding to the signal flow, inputs are always displayed on the left and outputs always on the right. Users can have either read or write access to the variables. The layout of the terminals and the color of signal flow lines provide information about the data type.
The parameters of the function blocks are also defined in the FBD program. As a result, parameter dialogs, in which all block-specific entries can be made, are available. Once completed, the FBD program can be verified using a plausibility check for errors or syntactic accuracy. Any errors or warnings are displayed in a list, and it is possible to go directly to the source of the error by simply clicking on the relevant line in that list.
The cross references in a program can also be displayed for the whole system. Here, too, the corresponding displays or programs with plausibility error messages can be called up directly in order to gain easy access to the variables or process points referred to.
An FBD program is configured as follows:
- Define name for FBD program
- Open editor for FBD program
- Select function blocks
- Position in the graphic area
- Connect functions with the signal flow lines
- Enter input and output variables
- Define parameters for the functions
- Check FBD program for plausibility
- Correct any syntax errors
Configuration of sequential function charts
The sequential function chart (SFC) readily allows transparent, graphical creation of sequential control programs. To create an SFC program, steps are configured with assigned actions (commands) and transitions with step-enabling conditions. Programs (function block diagram, ladder diagram, structured text, or instruction list) can be assigned to the steps and transitions. A further feature of the sequential function chart is the facility for creating alternative and parallel branches as well as the synchronization of these sequential structures. At the same time as the sequential function chart is configured, the SFC display for operation and observation on the operator station is generated automatically.
Configuration of structured text
Structured text is one of the text-oriented programming languages of IEC 61131-3 , in which program processing is determined by instructions. All functions and function blocks in Control Builder F can also be called in ST programs. The scope of the functions is partly covered by the ST operands. Function blocks can be used in the ST program following declaration.
Parameter definition of the function blocks also takes place in the same way as in the ladder diagram or function block diagram. In contrast to that of the function block diagram (FBD), the scope of functions of the structured text also includes conditional commands and loop commands, which are called using appropriate key words. The processing sequence is determined from the order of the commands in the ST editor. The only way to specifically change the order is to insert loop commands.
Configuration of instruction lists
All Freelance 800F processing functions can be defined by the instruction list (IL). The scope of the instruction list exceeds that of the function block diagram and sequential flow chart, as jump commands and program loops can also be programmed. The operands can be displayed and entered with a selection list according to IEC 61131-3. The functions and function modules in the function block diagram can also be called and integrated into the instruction list.
Parameter definition of the function blocks also uses the same parameter definition screens as those used in the function block diagram.
Configuration of ladder diagrams
Along with the function block diagram (FBD) and sequential function chart (SFC), the ladder diagram (LD) is also one of the graphical languages of the IEC 61131-3. The ladder diagram language originates from the area of electromagnetic relay systems and describes the flow of current through individual rungs. The boundaries of a rung are defined on the right and left side by devices known as power rails, which have the logical state 1 (current is flowing). A rung is created with the elements of the ladder diagram (links, contacts and coils).
Functions and function blocks in the ladder diagram can be called up and used in the same way as in the function block diagram. Parameters are also defined for function blocks using the same parameter screens.
More about Control Builder F see:
Freelance 800F System Description (pdf, 6.19 MB)
CBF viewer
For commissioning purposes CBF viewer is a tool to consider. It enhances CBF’s capability by providing independent work places for parameterization and loop checks. It has a similar view on the project like Control Builder F and some nice enhanced features like embedded face plates, extended SFC display, project tree filter, online variable list, parameter list for Tags, ...etc.