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IEC languages support in Cscape
Find out how Cscape supports the full IEC languages family.
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IEC article contents: |
What is IEC?
By IEC languages support we usually refer to IEC 61131-3, which is the third part of the open international standard. IEC 61131 was first published in December 1993 with its main purpose to standardize, simplify and support PLC programming.
Part 3 of IEC 61131 deals with programming languages and defines two graphical and two textual PLC programming language standards together with a system organisation tool:
- LD - Ladder diagram (graphical)
- FBD - Function block diagram (graphical)
- ST - Structured text (textual)
- IL - Instruction list (textual)
- SFC - Sequential function chart (has elements to organize programs for sequential and parallel control processing)
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Benefits of using IEC IEC standard gives us four clearly defined programming languages. SFC can be treated as a system organisation tool, which controls blocks written in other IEC languages. |
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Main benefits of IEC as a programming tool:
- reduced waste of human resources, in training, debugging, maintenance and consultancy
- focusing on problem solving via a high level of software reusability
- reduced misunderstanding and errors
- suitability for top down and bottom up development
- programming techniques can be implemented in a broad environment including general industrial control
- combining different components from different programs, projects, locations, companies and/or countries
Cscape Setup
Cscape has supported IEC languages for several years but since the version 9 was released, the level of integration of the tools was greatly increased providing a comprehensive environment to create, edit and debug all IEC programs. Everything is embedded within the core Cscape environment and fits perfectly within Cscape main window.
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A new configuration option ' Supported Program Types' has been added under menu Tools -> Application Settings. This option allows users to create new programs in Advanced Ladder or IEC Editor or both (dialog window will be displayed every time a new program is started). |
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If only 'Support IEC Editor Programs' option is checked any new program created will automatically be an IEC program. If both 'Support Advanced Ladder Programs' and 'Support IEC Editor Programs' options are checked the type of any new program created will be selectable (IEC or Advanced Ladder). In each case, opening an existing program will open it in its original mode with the appropriate editors enabled. |
There are two quick ways to add a new IEC module. Either go to menu Program -> New Logic Block or simply right click on the 'Main Loop Modules' item in the Project Navigator window and select the same option.
Sample Application in ST, IL, FBD, LD and SFC
To illustrate how easy is to start an application in any of the IEC languages let's take a look at this simple example. The goal is to write a code which will turn the first digital output ON, when F1 key is pressed (and stays ON when the key is released). And also turn the output OFF when F2 is pressed.
In our Advanced Ladder Editor the solution could look like this:
Now let's see how the same solution would look in each of the IEC languages. Each code sample is available for download (single file; Cscape 9.20 or higher needed). This application will work on any Horner controller equipped with at least one digital output. Here we'll use the XLe model 112 (HEXE220C112).
1. Structure Text (ST)
2. Instruction List (IL)
3. Function Block Diagram (FBD)
4. Ladder Diagram (LD)
5. Sequential Function Chart (SFC)
Now, bear in mind that in this case, the SFC will show its true potential when approaching complex and parallel processes. This example is too simple to show of all the benefits of this organization tool.
The biggest advantage of using the IEC languages is the possibility to use them all in a single application. That single fact allows you to create much more advanced programs which simply could not be accommodated using individual languages.
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