World Amateur Radio Day 2018

World Amateur Radio Day 18th April 2018

Celebrating world amateur radio day 2018 we look at the way pre internet, radio shrunk the world.
Using a variety of frequencies to transmit locally, or over long distances, radio ‘hams’ passed messages round the world long before there was Twitter, SMS or even phone calls. Relays passed on messages acting as go-betweens in the same way our major backbone carriers pass our messages today. However, it was all a little more civilised and ‘human’ rather than a hub of computers and machine readable protocol.

An sd representing an intial ham contact
Ham Sequence Diagram

So “CQ from 3SL, calling CQ three sierra lima and listening”

“Hello all on World Amateur Radio Day 2018! ”

To find out more about your local radio society,  head over to your countries associations.

International Amateur Radio Union

Radio Society of Great Britain

and local to us here in Cumbria Furness Amateur Radio Society 


Can I control duplicates on my hierarchy diagram?

Duplicates In a Hierarchy?

In the case of a standard hierarchy in a book, it is unlikely you’d see duplicates. Chapter 1 may contain paragraph 1 and sub paragraph 1.1. (A complete reference of 1.1.1).  Paragraph 1 in chapter 2 would be 2.1 and therefore, even though paragraph 1 is a duplicate number the full identity is unique. However, in an engineering context, it is much more likely that information will be referenced in more than one place. Hierarchy duplicates are not unusual for referenced information. After all, it is much better to store the information once and use it many times. This is one of the major benefits of a Requirements Management tool. Imagine each component that has to meet a certain design standard. It makes complete sense to relate each part to the  standard, rather than copying the standard numerous times. In this regard the hierarchy contains duplicates. For each part that is drilled down many  components will end up with the same standard at a lower level of the hierarchy.

Linked Hierarchical Information

The following example shows the expansion of a component (Pump) into the sub components (we’ve followed a link type of SUB-PART). The diagram shows that two of the components have to comply with specific flammability requirements. Both Pump Housing and Pump Electrical Control are linked to REF-13 for Flammability. In turn this has lower elements of Smoke  generation for plastics and flammability of Cables.

The diagram illustrates that REF-1.3 is a duplicate by the small square in it’s NE corner.

How to control expansion of hierarchy duplicates on a HID
HID Expansions

Controlling Expansion of Hierarchy Duplicates

The Hierarchy Diagram Properties dialog has an option to control whether items seen as duplicates are expanded to further levels. Here the Expand Duplicates option is unticked which is why the user does not see REF-12 and REF-14 expanded below it.


Related Articles

Make a Hierarchy Diagram (HID)

Can I control the shape of a HID?

April 2018 Newsletter

Happy New Year!?

Yes, I know it’s the April 2018 Newsletter. The Gregorian calendar was introduced in 1582. The switch by countries was gradual, with the UK changing in 1752. During the switch the UK lost 11 days in September, and the start of the year was moved to January the 1st. We covered some of the strange naming conventions in our October newsletter. Originally the first day of a ‘new year’ was 25th March, this sudden jump would have messed up financial institutions accounts. So they kept the start of the fiscal year more or less where it was, shifting by those same 11 days to 5th April. Or it could have been that the accountants were so drunk at Christmas they just couldn’t face doing the accounts when they returned to work. Take your pick. 

finance image from

So if you are lucky enough to be dealing with a new budget for the “new year” now’s the time to check you are getting value for money across all your projects. Are you still dealing with several different tools to manage your Requirements and model your Systems?
Could you consolidate these tools and methods by adding extra licences to your Cradle installation and then  on-boarding (yuck -Sorry read that one in a trendy blog post somewhere) the less enlightened?
On the other hand if you’ve been Spring cleaning and found your project a little out of kilter, you may realise that the management view you have over it,  is not as clear as it ought to be. Then maybe adding a Dash or Metric licence to Cradle could help with getting to grips on the health of your project. However we can help, don’t hesitate to call  us here in the UK or your local distributor.


Measurements and collation of the results are an important management tool.

metrics in Cradle

It is obviously important to manage and track the right thing. Using the ludicrous  quote “The majority of people involved in accidents were wearing white underwear….”, you may jump to the conclusion that brightly coloured pants will keep you safe. Of course this statement is completely meaningless without context because if white pants are the most popular colour you could make that statement apply to any topic.

Provided you are measuring sensible information, percentage of  Requirements that are Accepted, or Underway gives a really useful view about the maturity of your project.

In Cradle you can define any number of metrics, save and re-run them at a later date. A metric is made up of a set of elements, each element is a query to the database to retrieve item(s), and an analysis operation on these items. This could be a simple count, or a more comprehensive coverage analysis of attributes.  Available functions include:

  • Item count
  • Minimum value, Maximum value
  • Averages/spread (mean, median, mode(s), variance (population-based), range, standard deviation (population-based) and semi-interquartile range)
  • Total / Weighted total of values
  • Range of values
  • Pivot table for category values
  • Coverage statistics

The returned values can also be further manipulated with  Metric calculations, combining values with basic mathematical operations. Delve into the help section for more information or read the flyer.

Cradle Features Coming Soon….

As we mentioned in February Cradle 7.4 is on the way. Look out for; New colouring options in (HID) Hierarchy Diagrams,  Additional Regex (regular expression) matches in queries,  Unique attribute checks……..

Social Media


Yey! Our followers still steadily climbing, but will you be the one that pushes us over the 400 mark?? What happens when we get to 404, do we get Follower Not Found? (Oh dear, sorry,  bad engineering joke crept in. Ed.)

screenshot of @threesl on Twitter
Twitter Account

We read how conventionally CO is seen as bad, but there could be a route to making fuel.

We gave you a peek inside 3SL towers at some of the great staff we have.

We found ourselves hungry on St. Patrick’s day.

And took comfort that we were missed…..

Hints of the Month

Last month’s blog articles included:

We highlighted types of storage in Cradle, last month. Think of this too as a way to get tighter control over some of those files that form part of your Requirements set. Adding them to a Cradle item and then adding meta data to describe how they fit into your project.

We also looked at setting your model drawing preferences.

And to fit in with our Spring Cleaning, some housekeeping tips in Cradle.

You can read Hints & Tips in the 3SL Blog

What is a System?


[sis-tuh m]noun:  an assemblage or combination of things, parts, sub systems, members, operations or principles forming a complex or unitary whole.


To answer the question ‘What is a System?’ you first need to understand your context. When you get down to the ‘atomic’ level for your component parts you’re unlikely to model them any further. A local authority may want to model their transport system. This may include vehicles, termini, and ticketing systems. Whilst their model may include the external specifications of a bus (in terms of weight and width) to plan a terminal, they are unlikely to care whether the bus electrical operates on 24v or 48v batteries.  Unless they have to supply charging points at the depots. The tram’s external specification would again include width, height and mass, but it is very likely that the authority would need to know the electrical operation characteristics in their model if they are responsible for the track.

illustration of systems and context
System Components

The bus manufacturer is not really interested in how the local authority terminal looks or operates. However, they may have design constraints for the width or length imposed by their customer. Being able to identify these parameters in their design will help them design any modifications needed to meet the requirements. Some times there is need for shared information. The ticketing system may be supplied by a third party, both the council and the bus vendor will be interested as part of that system will fall within their responsibility. Ticket sales at the terminal, ticket machines fitted on the bus. The bus manufacturer will undoubtedly model their vehicle, there will be detail plans of what connects to what and what operational parameters are needed for each. In this way if a new component is introduced, it is easier to see the impact. The new air conditioning unit needs 48v supply, the bus currently uses 24v how do we assess the impact and know what is dependent on the current voltage line?

Should I model X?

Whether a system, or sub-system is worth modelling heavily depends on your position in the project chain. Deciding whether this is ‘atomic’ level for you is very dependent on your industry. Assessment should be made as to  the likelihood that parameters of the component may affect higher level systems. The likelihood of whether a subsystem is going to be re-used in a number of different high level systems, and whether stakeholder or external constraints need to be considered.

modelled low level components
Circuit model

If you make capacitors, you’ll have specifications for the capacitor, it’s voltage, capacitance, temperature range and so on. However, there is not much you can model at this level. If you also make wire wound inductors, then it will have similar specifications. However, as soon as they are linked together forming an LC oscillator, you have a system. There are two components who’s characteristics interact. If the LC sub-system is being supplied then the voltage at which it is safe to operate will be dictated by the components within. In this case specifying the inductor and capacitor as blocks with characteristics that form the internals of the oscillator will have a benefit in future design or specifying the operation of the sub-assembly supplied to onward customers. As the vehicle parts designer wanting to make a turning indicator unit, whether the oscillator is LC, RC and Transistor or Op-Amp is of little concern as long as the voltage, current and timing are correct. The oscillator would therefore be the atomic level here. The bus designer is not worried about the indicator unit design as long as the brightness and timing meet regulations and the longevity and power consumption are within performance parameters. They would have no interest in modelling the oscillator.

Model Benefits

Query showing relationships
Linked Specification

The fact that your model contains detailed information of the interconnections, parameters and ranges of your atomic components makes querying your model to analyse change much easier. Being able to identify all components that are expecting the same power will aid a designer in assessing the impact or running a different voltage.

Can you model anything?

Pretty much any system can be modelled. Software was maybe the original stable from which many modelling techniques originated, there is a need to define at what point each module interacts with the other modules. The depth to which the functions are modelled will again depend on the context. There would be no point modelling the printer driver in the system beyond the interface, if that driver is purchased along with the printer hardware. Library functions may be modelled in their own right, but the higher level designer will reference them as white or black boxes.

No one model has to contain everything. The passenger movements, purchases modelled as use cases. The hardware components forming the bus. The sub components forming the indicators. The software controlling the ticket system are all separate systems working as a whole.


Near Miss Day

Near Miss Day – Celebrating on 23rd March 2018

Odd to celebrate something that didn’t happen. However, a large asteroid missing the Earth by 500,000 miles in 1989 is probably something to be thankful for!

We celebrate every time we are able to deflect word processors and spreadsheets away from engineers and businesses trying to achieve requirements management.

Near miss a spreadsheet and word processor nearly got use for requiremetns management onearth
Near Miss

Protect Yourself

Ensure you use the right tools for the job and don’t get tangled up in a bunch of uncontrolled, inadequately linked statements against which your project will be developed. Use the protection of a Requirements Management tool with a proven history, that can control, configure and provide full traceability. We’d obviously recommend Cradle!  So take heed and ensure you don’t have a near miss day at work.


Keeping Cradle in Tip Top Condition

This article will highlight a set of housekeeping tips to keep Cradle running smoothly and provide a good user environment.


Whilst alerts are a very useful feature telling users  that an aspect or item of their project has changed, users sometimes forget to clear their alerts from their accounts. You could ask each user to select old read/unread alerts and delete them. However, an administrative user with both PROJECT and ACCESS_BYPASS privileges can tidy alerts for ALL users

how to tidy up alerts
Housekeeping Alerts

Selecting the Project tab, then Delete Alerts will show a dialog that lets the administrator choose a range of ALL users’ alerts to delete. This will remove read and unread alerts from the database.

Automatic housekeeping for alerts
Project Setup – Alert Management

Additionally Alerts can be tidied up by each user automatically each time they log out. This setting can be found in the Project Setup under Alerts.


These can include Queries, Views, Forms, Matrices, Metrics, Reports, Graphs, Dashboards, Navigations, Start Pages, Graphics Print Settings, Hierarchy Diagram Properties, Capture Setups, Report Styles, Graph Styles, Export / Import Formats.

They are stored in different groupings, Personal, Project, User, Team, User Type, System and Automatic. These groups allow the definitions to be shared according to their intended use. Project for example is available to everyone working on that project, whereas User Type definitions match someone’s role on that project and are available to users holding that role. Personal definitions however, will be available to that person, across projects.

Sometimes duplicates or old definitions can accumulate and need tidying up. The definitions manager allows users to manipulate.

From the Project toolbar selecting the Definitions Manager will show the following dialog.

showing the definitions manager
Definitions Manager

Using the side buttons, definitions can be moved, copied and deleted. This would allow, say a team leader with creation privileges, to develop a number of queries or views and then move them into User Types for use by users who are not allowed to modify or create the definitions, themselves.

Depending on the location of the definition users may need one or more privileges from CREATE_DEFS, PROJECT, TEAM_LEADER or indeed ACCESS_BYPASS.


The DISAM database file system used by Cradle consists of file pairs of data and index files. After time, it is possible, that a number of blank areas will appear in the data file, as a result of large numbers of records having been deleted. Whilst this is perfectly normal operation, it can mean the data file is larger than it needs to be.

running dpack on DISAM files
dpack Utility

The DPack utility can be used to re-write these files more compactly and rebuild the indexes. This is not considered an everyday operation and would normally only be performed by and IT administrator. This should only be performed when the CDS (Cradle Database Sever) is not running.

  1. Make sure you have a backup of the entire project directory – incase a power-cut or machine failure occurs during crucial operations
  2. Move to the directory to be compacted
  3. Run the following command (c_dpack on Linux, dpack.exe on Windows®)
    "%CRADLEHOME%\bin\exe\windows\dpack.exe" tlb1alrt Where tlb1 is the project code and alrt is the particular database file to re-pack.
  4. To complete this for all files in the directory running a batch-file or script
    e.g. on Windows®
    @echo OFF
    for /F %%f in ('dir /B "C:\Data\cradle_projects\TLB1\*.dat"') do (
       echo Processing file %%~nf
       "%CRADLEHOME%\bin\exe\windows\dpack.exe" %%~nf

    Where C:\Data\cradle_projects\TLB1\TLB1 is the directory for the project.

Cradle History

Keeping track of what you’ve been doing is really useful, the history sidebar shows the queries you have run and the items you have opened.

However, sometimes you may have a long list of entries from a particular day, you may then want to work on a different part of the project. In this instance it is sometimes useful to clear your history and start afresh. In the History Sidebar you can choose what to clear by selecting and right clicking items in the menu.

Options for clearing Cradle history entries
Clearing History

Larger amounts can be cleared through the Clear Browsing History option on the Project tab

Related Articles


10 Steps in Cradle Performance Tuning

Cradle History

Diagram Preferences

Drawing Just the Way You Like It

We all have our preferred way of doing things. Whether that’s a corporate or a personal view. 3SL don’t enforce a particular layout style, colour or size. These diagram preferences can be set by the user. As with any preferences, they can be set at an installation level in the cradle.ini file on Windows® or .cradlerc file on Linux® file as a default or overridden by the user.

Grid Preferences

In the diagram below  it can be seen that the drawing grid is quite small (32). Which is great for finer detail. However, if you are mainly concerned with large blocks in your diagrams and want plenty of space, a layout guide of 128 may be more appropriate. Users have two options, firstly to set the size each time they use Cradle from the Grid section on the Diagram  tool-bar or to set their drawing preferences.

setting the grid preferences for diagram drawing in Cradle
Diagram Preferences

Preference Dialog

The dialog can be opened from the Preferences option on the Home tool-bar. Once the dialog is displayed, the diagram preferences are set using the the Diagrams section. There are a number of defaults that can now be set ranging from the initial grid size to whether specifications are automatically created when the diagram is saved.  You can change the palette too, so a mute background rather than bright white can be chosen to be easier on the eye.

Related Articles


Symbol Colours and Defaults


March 2018 Newsletter

Heading to Spring

As we head into Spring, most of us are keen to leave behind the horrible weather that came with the Beast from the East. Some of the worst UK snow seen in years. We’re happy to say that Barrow-in-Furness saw

snowy road by
Snow Problem

little impact and the support team were able to maintain full levels of service. We hope your businesses were not too badly affected and that you are all heading back to normality.

The question this raises is why are we so bad at coping with a bit of snow here in the UK?

The main problem seems to be that we’re not used to it. It is not a ‘steady state‘ in parts of the world where winter = snow and ice for a set period, the infrastructure is set up to cope. Cars have winter tyres or snow chains,  heated highways or rails keep cars and trains running, or there is value return on investing in ploughs and gritters. The changing requirements of British weather conditions would need you to put the snow chains on and take them off on a daily or even town by town basis. These changing requirements make managing the situation really difficult.  The same logic applies to projects, stable requirements make for a simpler solution. If your requirements are more like British weather, there is even more need to have a formalised approach to managing them. Making sure you can track the changes and your reactions to them becomes imperative.
Don’t end up wearing wellies in the summer and flip-flops in the snow, get you requirements under control in Cradle and encourage your suppliers to do the same.


padlock over computer based on images from on

We can assure you that we don’t randomly buy email addresses and send spam adverts. We collate our communication list from curated information from you, our customers and prospects. People and companies who have contacted us about RM / MBSE / Cradle or 3SL. We maintain these dialogues as a legitimate business interest. We have made, and will continue to make, it easy for individuals to ask for their contact details preferences to be changed. We look forward to staying in touch with you all.

If you have any GDPR comments you’d like to feature contact us at

Social Media


study shows 47% or projects can fail because of inaccurate requirements management
Project Failure Statistic

We were a little disappointed at the  #SuperBlueBloodMoon over Barrow.

We were amazed at the accuracy of NASA’s clocks

..But appalled at the failure rate of projects.

Hints of the Month

Last month’s blog articles included:

We answered a question about producing a Hierarchy Diagram (HID) for viewing in Web Access.

The different ways you can store data in Cradle’s frames a how and why guide.

We also looked at how to control access to data parts in an item.

You can read Hints & Tips in the 3SL Blog

Fun Facts About Names Day 5th March 2018

Fun Facts About Names Day

A bit of #MondayMotivation, this light heated day is celebrated on the first Monday of March. Have a ponder to think where you came from, what lineage came before you. Despite #FunFactsAboutNamesDay sounding like something Sheldon Cooper (Nerd Alert: Big Bang reference) may present it is a real ‘day’. So while you’re having your first cuppa (Good British drink of the day) or at the ‘water cooler’ (Is that really a thing??). Challenge a colleague to a Fun Facts About Names!


Some are fairly obvious “Smith” and “Cartwright” working in a smithy or making carts. Some a little more tricky “Chalker” one who applies white wash. Then there are the more obscure, lost meanings in time, “Lister”,  a dyer of cloth. (Maybe someone should tell Dave Nerd Alert: Red Dwarf reference)



So where did we come from? Structured Software Systems Limited ⇒  SSSL3SL that simple really!