CoDeSys on CCP XS for Bromma Conquip - Research

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Student Joel Ek Supervisor at CC-Systems Fredrik Löwenhielm Dok Nr 1.0 Date 2006-08-08 Rev PA1 Säk klass F Filname Thesis.doc CODESYS ON CCP XS FOR BROMMA CONQUIP 4.1.3 Selecting language for component board application The goal with the component board application in <strong>CoDeSys</strong> is that it should function in a similar way as ABE. That you can build up component-scheme by choosing the components you wish and connect them to each other. There are four graphical languages in <strong>CoDeSys</strong>: - Ladder diagram, the ladder diagram is most suitable for creating program describing electric circuits. - Sequential function chart, Sequential Function Chart is most suitable if the program can be divided into steps and run in chronological order. - Continues function chart, it is very similar to FBD but has some additional features like feedback paths back directly to the POU and the possibility to decide the order of execution for the different components (fig. 14). - Function block diagram is used to connect different Functions and Function Blocks, both standard and user defined. The signal flow always go from left to right in the diagram it is also divided in several networks to make it more perspicuous (fig.13). The obvious reason for using the Function Block Diagram is that we are representing the components with Function Block POUs. ABE also use networks 16 when designing the component board. Furthermore, there is no interest in changing the order of execution for the different components, making the use of CFC unnecessary and in some case makes the system more prone to mistakes. Figure 13: An example of a FBD with two networks. There is nevertheless one big problem with FBD, it is not possible to decide in full how to place and connect the components in the different networks. If we look at the example in figure 13 we have already two networks and it is not possible to perform this connection using one network. 16 In ABE the networks are known as rungs 26 (55)
Student Joel Ek Supervisor at CC-Systems Fredrik Löwenhielm Dok Nr 1.0 Date 2006-08-08 Rev PA1 Säk klass F Filname Thesis.doc CODESYS ON CCP XS FOR BROMMA CONQUIP This is due to the fact that we can not continue connecting components in the same network unless we use the most upper output, in this case the sigOutCounterValueM output. Even if we use it, we still need a new network for every lower output you connect to. Some of the components that are in use on a spreader system from Bromma today have over 20 outputs. To use FBD with one of these components fully connected would lead to over 20 networks and the outline of the Component board would be difficult to grasp. This rule for connections is just a fact and the recommendation from 3S regarding more complex systems is instead to use CFC. The same scheme as in figure 13 would in use of CFC instead look as figure 14. Figure 14: An example of a CFC With CFC it is also possible to position the components in any way we want, with FBD the components is place automatically. One possibility if you don’t wish the scheme to grow to far to the right is to use connection markers so that you can start from the left side again (fig.15). Figure 15: Showing the use of connection markers in CFC 4.1.4 The setting of component parameters When designing the component board in ABE it is possible to alter specific information for the components. The general way to do it in <strong>CoDeSys</strong> is to either set the internal variables for the Function Block when declaring it or to initiate the instances of the Function block when they are used in a program (fig. 16). 27 (55)
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CoDeSys on CCP XS for Bromma Conquip - Research

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