Map functions to signals

[royvanmarrewijk]

Hi,

For an industrial automation project I would like to design with which inputs and outputs soms functions are realised. For example the electrical designer designed that we communicate with an frequention inverter via analog signals 4-20mA and we use a digital signal to store the selected frequency. My functional design uses SetFrequency to describe this functionality and now I would like to use something like a sequence diagram to create a mapping.

What do you think is the best way to realize this? I allready experimenting with (SysML) flow properties to define the signals but I can't use this in sequence diagram.s

Roy

[qwerty]

SysML is the right way to go 

q.

[royvanmarrewijk]

Haha thanks! Can you maybe tell me how to use flow properties in a sequence diagram? Or how to describe behaviour using flow properties.
Roy

[PeterHeintz]

Hi,
I do not understand what you want to do!

What do you want to map?
Do you want to map your converter interfaces to your PLC interfaces (structure) or to behavior withing you PLC.

In general sequence diagrams are from my point of view not intended to do mapping.

[royvanmarrewijk]

Hi,

Ok, let's see if I can draw what I want to have

                                      ________                             ________
                                     |                |                         |                | 
                                     |    SW       |                         |     HW     |
                                     |________|                         |________|       
   SetFrequency(50)               |                                          |
----------------------------->|                                          |
                                              |       oSetFrequency(50)     |
                                              |--------------------------->|
                                              |       oStoreFrequency         |
                                              |--------------------------->|
                                              |       iAccept()                     |
                                              |<---------------------------|
                                              |                                           |

I would like to create flow properties which I can use to define the signal information (direction, upper / lower limits, engineering units etc.) And I would like to describe behaviour using this flow properties.  The goal is to design a driver (hardware / software connection) and this requires time / sequence depended behaviour.

[qwerty]

A SD can only show actual parameters in a flow. I think a block diagram is much better suited to show the connections and what actual "flows" between them. The reason for my short answer was, that the long answer is: read the SysML specs and learn how to use it. It takes a (large) bit of practice.

q.

[PeterHeintz]

Ok, let’s assume this:

You have two structure elements SW and HW. Both are connected with an interface to handle frequency somehow.

The two structures you represent in SysML with Blocks (more or less a UML Class).
The overall frequency interface you represent with a port (I do not use nested ports to keep the things simple).

To give your port more information you create another Block maybe called “FrequencyPort”.
Before filling that block with information you decide from which side you want to specify the information (let’s say from HW).

If you do not want to define the features in the “FrequencyPort” directly, maybe because your Port could also work with other features, you add a flow property and a “FrequencyFlowProperty” block (I would probably not do in your case).

The port you classify with “FrequencyPort” and the flow property with  “FrequencyFlowProperty”.
Either in the “FrequencyPort” or in the “FrequencyFlowProperty” you add the provided feature operations oSetFrequency() and oStroreFrequency() and the required feature operations iAccept (above decided to do it from HW side).

Your HW port you classify with “FrequencyPort”, yous SW port as well, but Advanced/IsConjugated set to true.

Within your SD you drag and drop the SW and HW blocks. For both make your ports (or additional your flow properties) visible by Context Menu/Structural Elements… feature.
Create your messages and select you operations.

[royvanmarrewijk]

Hi Peter,

Thanks for your reaction!
I created the example and I run into a problem when I choose the solution with the flow property. I created the "FrequencyPort" Block and within this block I created a Flow Property and typed this with the "FrequencyFlowProperty" block. I think I can't select the operations because the flow property is nested within the "FrequencyPort" Block and it isn't a structural element. So can you tell me how you created the flow property so you can select the operations in the SD.

Roy