IEC-EN 60204-1-And-81346-September-2010

Systems A shortcut to manage complex designs

FREE SAMPLE by compliments of Balslev & Jacobsen ApS Vestergade 6 - 2nd. floor. DK-1456 Copenhagen K. Denmark www.balslev-jacobsen.dk & www.81346.com

Henrik Balslev 2013-02-08

Executive summary Do you struggle with messy designs and have lost the overview? Or has your design just got more and more complicated over time, so only a few key-people can handle it? Well, this brief introduces the system approach as the strong and long-lasting reliable tool to sort that problem out once and for all. I have provided some examples as well, just so you can see how easy and effective it is. However, you need to adapt the principle for yourself, and make an approach which fits your own design to make it work properly. I can guarantee you will benefit from making the effort, as I have helped a lot of various disciplines to do so already: From concrete factories, district heating companies, building industries to oil platforms etc. which is transformed from unclear and esoteric to clear and easy-to-understand design approach by the use of system engineering principles. It is very easy and straightforward, once you are familiar with the technique. If you need assistance, would like to give feedback or have questions, you can find my contact details on www.balslev-jacobsen.dk Kind regards Henrik Balslev Partner, Specialist

Table of content Introduction ....................................................................................................................................... 2  What is a system? ............................................................................................................................. 3  Basic .............................................................................................................................................. 3  What systems are about ................................................................................................................ 3  Some of the benefits of systems ................................................................................................... 4  How to handle large designs ............................................................................................................. 4  Basic .............................................................................................................................................. 4  Identification of systems and their parts ........................................................................................ 5  How to start ....................................................................................................................................... 6  General.......................................................................................................................................... 6  Tools for structuring....................................................................................................................... 7  More than one structure? .............................................................................................................. 7  The key to interfaces ......................................................................................................................... 8  Example 1 - Aircraft main systems ................................................................................................. 10  Example 2 - Human systems .......................................................................................................... 11  Example 3 - Building main systems ................................................................................................ 12  Bibliography .................................................................................................................................... 13 



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Systems - a shortcut to manage complex design by Henrik Balslev

Introduction This is a short introduction to the application of systems and the use of this approach to handle complex designs within all kinds of engineering designs such as the industry processes, building construction, machinery, aircrafts, ships etc. However, you do not need to be an aeronautic spacecraft engineer to get full benefit of the system approach, as it almost fits all. To view the world as many different ‘systems’ is not a new idea, and is widely recognised. Especially within engineering designs which increase in degree of complexity and interrelations, the system approach will be the strongest tool for you to handle it.. However, to my knowledge, there are still many engineering designs which do not know or recognises the power of this mechanism, and therefore I took this opportunity to make a short introduction to the scope with some examples from projects I have made recently.

Figure 1- A schematic representation of a closed system and its boundary (Wikipedia)

The main trick about systems is to collate components which work together and call that specific collection for a ‘system’, for example ‘electrical system’. By doing so, you can monitor the systems of interest and the relation to all other systems. It is just as easy and smart as it sounds! From an engineering perspective, the system approach is known as systems engineering, which covers much more than just chop complex designs into systems, but also items as change requests, interfaces etc. INCOSE is an international organisation of interest in this matter.



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Systems - a shortcut to manage complex design by Henrik Balslev As I am an engineer which has specialised in structuring of complex design information, I have decided to use the term ‘systems engineering’ in this introduction, however with the limit of introducing the basic nature of systems and their relations only.

What is a system? Basic Depending on who you ask and the purpose of the systems, you can find more than 30 definitions of the term system. I prefer the ISO/IEC 15288 (2008) definition of a system:

interacting objects organized to achieve one or more stated purposes

In general, we often talk about objects, which is just about everything you perceive or think of. From an engineering point of view, the term object is often a technical object. It is then a fact, that all technical objects can be seen as systems.

Systems are seen as levels of abstraction:   

The higher level - the higher abstraction. Each level can be explored individually and with individual sets of details. Systems composition allows you to hide or expose sub-content as appropriate.

What systems are about I have seen many designs (generally spoken) which is a result of development from something originally very simple to something very complex and sophisticated technique. It is the time and general development which causes this, which is quite natural. However, what also happens is that the design gets more and more esoteric and requires a long training period to get new employees or sub-contractors to get introduced to. The risk of mismanagement and unsuccessful operation of any complex device is imminent. Don’t you think it would be nice to have the same ‘technical language’ within your company, so all departments knew exactly what one another was talking about, and in addition get the easy tool to handle the complexity of your design? Well, ‘systems’ does this trick for engineers! No matter how you slice it, systems engineering is all about applying discipline to the full life cycle of any design. That discipline comes in two distinct flavours:



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Systems - a shortcut to manage complex design by Henrik Balslev 

Technical discipline ensures that you rigorously execute a sensible development process, from concept to production to operation.



Management discipline organizes the technical effort throughout the system lifecycle, including facilitating collaboration, defining workflows, and deploying development tools.

This brief is about the technical discipline only.

Some of the benefits of systems Perhaps most importantly, the system discipline provides a synchronization point across multiple engineering disciplines, offering a solution the most significant problems in the development of smart systems:



how to identify interfaces (who is depending on what in the design) - see N2 diagrams.



how to coordinate hardware and software (how to make it work together)



how to increase effectiveness (for example by re-use designs)

How to handle large designs Basic A system often consists of sub-systems in different compositional levels. By subdividing, or structuring, a system in sub-systems, using part-of relations, even very large sets of information in a complex design can be handled efficiently. Compositional structuring provides an excellent overview of a system because composite structures based on partitive relations are simple to understand, establish and modify. So compositional structuring is the key to handle complexity for you:



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Systems - a shortcut to manage complex design by Henrik Balslev

Figure 2 - Illustration of sub-division of a main system

In Figure 2 any sub-system may be equivalent with a component. The trick is, that you just subdivide any system to the point of interest for you, and never goes for a fixed division (for example ’always three levels’), as this will limit your design. The depth of the structure, i.e. what is included and what is not included, is diverted from very different needs depending on discipline and point in life cycle. NOTE: Composition is also recognised as ‘Part-of relation’, ’partitive relation’, ’part-whole relation’ or ’whole-part relation’.

A part-of relation is smart, because it allows a designer to handle wholes (as distinct from parts).

Identification of systems and their parts Parts of a system may be identified using different aspects, e.g. functional parts, material content parts, and work process parts. The structuring principles recognize the stage within the life-cycle as important for the application of different structures based on different aspects of the system.

ISO/IEC 81346 standard series, known as the RDS standard (Reference Designation System) is an international standard which provides rules and guidelines for preparation of identifiers of systems and their sub-systems and/or parts. This is smart, as you can establish easy recognisable and human understandable identifiers to support your design. The ISO/IEC 81346 standard is widely supported by various IT software, typical with an origin in electrical and mechanical diagramming, but now a days in a more wide approach.



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Systems - a shortcut to manage complex design by Henrik Balslev An identifier based on RDS is called a reference designation. Examples may look like this: Reference designation -GG1-E2-F1-EM6

Means Kiln System no. 1 (GG1) Kiln Burner no. 2 (E2) Fuel control system no. 1 (F1) Pre-mix unit no. 6 (EM6)

-C1-Q1-QM2

Pump station ‘Steinbruddet’ (C1) Valve system no. 1 (Q1) Main valve no. 2 (QM2)

+KLE+2

Location Klemetsrud (KLE - a place in Oslo, Norway) Level 2

=J1=HE01

Ventilation system no. 1 (J1) Ventilation plant no. 1

RDS supports system engineering and the basic philosophy of structuring. It will create identifiers (TAG’s) for you, which never runs out of range, as it is based on part-of relations. Please visit www.81346.com for more information.

How to start General The good news is, that any designs you may have today already are systems - you just need to identify them! There are various ways to do this, but you can try this recipe out:





The structure is created “bottom-up”, i.e. the structure is formed as “part-of”. This means that any component always will be a-part-of a systems.



So first, you collect components that usually work together, and call this new collection “system 1” - you can later decide a more appropriate name for it.



And so on, until you don’t find any more components.



Then, you need to see if these (low-level) systems comprises a system on a higher level. If so, then give the high-level system(s) a practical name.



And so on, until you don’t find any more systems.



That’s it!

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Systems - a shortcut to manage complex design by Henrik Balslev Hint: You will typical need what is called ‘infrastructure systems’ which are system that are there to help other systems work. Such examples are electrical power supply systems, drainage systems, water supply systems, control systems. They are systems just like any other systems you can identify.

When you have created a structure, you have in fact created a model of your system!

Tools for structuring I am often asked for a recommendation of software which can help you to sort out your system design. I often recommend ‘mind maps’ as it is very easy to re-arrange the part-of relations as you go. Most humans grasp mindmaps and the way they works very quickly and love to work with them. You can google ‘free mind maps’ or alternative buy a professional one. My personal tool is MindMap from MindJet, but there are others as good as them. When set with the structure, you can export it to another format and start making documentation based on your brand new system view.

More than one structure? Yes, you will probably realise, that you need more than one structure to monitor and control your design. The typical needs are functional structuring, product (assembly) structuring and location structuring (but not limited to this). ISO/IEC 81346 supports this point of view as well by using different aspects recognised as prefix signs (=, + and - sometimes ==, ++ and --) to identify which structure you are talking about. From a pragmatic point of view, it is relevant to make just one structure as a start, derived for the different requirements, as this will result in an overall structure which is clear and relevant to all disciplines. Later, when realising that you need to make compromises in you structuring, you can apply different aspects (based on RDS) to sort this out. The use of aspects is an ‘add on’ to your structure, which makes your system design very clear and unambiguous. Many IT systems (e.g. diagramming tools) support this too.



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Systems - a shortcut to manage complex design by Henrik Balslev

The key to interfaces “The devil is in the … interface!” Once you have identified your systems, you can gain the benefit of identifying all interfaces among these in a very systematic and straight forward way. There are lots of practical and economic benefits to gain, if you become the master of interfaces. Here is the trick: You can use the N2 chart to do so. The N2 chart was invented back in the 1970’s but is still a strong and easy way to get an excellent overview of all interfaces in a few steps.

External input to S1 – S2 – S3 – S4

System 1 (S1)

S1->S2

S1->S3

S1->S4

S2->S1

System 2 (S2)

S2->S3

S2->S4

S3-S1

S3->S2

System 3 (S3)

S3->S4

S4->S1

S4->S2

S4->S3

System 4 (S4)

Figure 3 - The N2 chart Interface Control

The N2 chart is a matrix with all systems (on the same ‘level’ e.g. main systems and not their constituents) represented on the diagonal. Outputs to inputs go clockwise: For example Output from S1 to Input S2 is above the diagonal, and Output from S2 to Input S1 is below the diagonal (see Figure 3).



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Systems - a shortcut to manage complex design by Henrik Balslev Example.

Discharge

Public power net

Fresh air

Below you can see an example of how systems in a building have various interfaces.

Cooling & Heating system

Cooling Heating

(none)

Status

Heat Exchange

Ventilation system

(none)

Status

Power supply

Power supply

Electrical system

Power  supply Status & Error

Control

Control

(none)

Automation

system

Figure 4 - Examples of interfaces among systems of a building

Here is how to read the example: 1.) The “Cooling and Heating system” provides cooling and heating to “Ventilation system”. 2.) The “Electrical system” provides power supply to all other systems. 3.) The “Automation system” controls the “Ventilation system” and the “Cooling and Heating system”. 4.) And so on…

Please see chapter “Example 3 - Building” for further building systems.



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Systems - a shortcut to manage complex design by Henrik Balslev

Example 1 - Aircraft main systems

NOTE: An aircraft consists of many main systems. Only a selected range is displayed. Each main system is to be divided into sub-systems, sub-sub systems and so on.



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Systems - a shortcut to manage complex design by Henrik Balslev

Example 2 - Human systems

See www.innerbody.com for more information. Did you know, that you comprises 11 main systems (see above)? You are built of approximate 60 basic components of which some are single (your heart for example) and some are multiple (for example your teeth). An adult comprises of approximate 300 components in total.



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Systems - a shortcut to manage complex design by Henrik Balslev

Example 3 - Building main systems



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Systems - a shortcut to manage complex design by Henrik Balslev

Bibliography You may explore more details about systems and how to manage them by study the following:

1.) Wikipedia Search for ‘systems’ and ‘N2 diagram’ 2.) SE for dummies by IBM Download PDF version for free. 3.) NASA Systems Engineering Handbook From 1995, but still worth a view. Free stuff. 4.) INCOSE SE handbook version 3.2.1 You need to become an member of INCOSE to download it, and it is worth the fee. 5.) ISO/IEC 81346 standard series (part 1 & 2) You need to purchase it or buy the guide handbook on www.81346.com.

‘SE’ means Systems Engineering



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