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Simple Clock Modeling with SysML

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It has been a while since I posted my previous article on this blog, because I was busy in making MagicDraw SysML supports for the new OMG SysML v1.3 Specification [1]. Couple weeks ago, I was asked by a customer about how to model a clock which counts every second with SysML. I created the simple clock model for answering. I also posted it to the SysMLForum and found that some people are interested in my clock model. So, I wrote this article to explain about the clock model and show how to model the system operating by a time trigger. Start from defining the clock with a SysML block. The clock block contains only a value property t . This value property represents time in second. Thus, a value type Second must be defined for typing the value property as in Figure 1. Figure 1 - SysML Block Definition Diagram of Clock Model Next, SysML State Machine will be created to describe the behavior of the clock block. Here, the clock state-machine was designed to have only one state
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Decomposing Ports and Connectors with Association Blocks

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This article was written when SysML v1.3 specification is in releasing process. If you are a big fan of SysML and keep in touch with SysML RTF, you may have seen some documents or books about SysML v1.3 such as [1] and [2]. One of many things that I am impressed in those books and documents, is the way they use SysML to describe nested ports and specify compatibility between connected ports using association blocks.  When two ports connected by a connector, they may have nested ports which themselves can be connected. An association block has been suggested for defining the internal structure of the connector. It could contain a set of connectors that define the connectors between nested ports of association ends. When a connector is typed by an association block, the interaction between roles at both ends of connector will be handled by the internal structure of the association block [1].  This approach give us not only the ability to decompose ports and connectors but also the a
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A Common Misunderstanding in Using Connectors

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I have been asked many times by customers, that why they cannot use a connector to connect between ports on the boundaries of blocks in SysML Block Definition Diagram (BDD). Is that a tool's problem? After I have answered this question many times, I think it would be helpful for SysML users if there is an article to answer such question. For easy to explain, please see Figure 1. My customers try to use a connector to connect port p1  of SubSystem1 to the port p2  of SubSystem2  but they cannot. So, they have asked me with above question. Figure 1 -- SysML Block Definition Diagram To answer it, we should start by asking ourselves that does it make sense if a connector can connect both ports together? What should be the meaning of that connection? especially when we have multiple instances of SubSystem1 and SubSystem2 . Should the ports p1 of all  SubSystem1  instances be connected to the ports p2 of all  SubSystem2  instances?  I don't think so. BDD is used to
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