I have been designing small to medium sized Process Control systems for
several years without using any formal design methodology. However, as
my projects are starting to get larger and more complex I am finding
that I am needing a more formal strategy.
I'd like to hear your feedback and experiences with design
methodologies out there that are most suitable for Process Control
applications. I'm interested in ideas on everything from generating
specifications to program design to testing and documentation.
What Industries are you in? (Process Control is a wide enough field that
knowing your specific field might help us to point you at your industries
codes of practice on this).
Fortunately, all industries have some commonality for development processes
that some general tips can be given that would be useful.
Let us start with a couple of standards. ISO9001 is a quality control
standard for developers. IEC61508 is a generic standard that relates to the
functional safety of your process control system (specific industry sectors
are developing their own based on this). Within this document you will find
reccommendations for key aspects of development processes (the stages and
considerations to be included) and implementing those will stand you in
reasonably good stead.
If the development processes indicated in IEC16508 seem a bit complicated
for you to get your head around you are welcome to adopt my simpler
approach. This is based on knowing what documents you must deal with
throughout the development. This will range from the customer requirements
that are handed to you and the standards and legislation that apply to your
products; task analysis reports; through hazard identification and risk
assessment; technical specifications and test plans; functional and
non-functional specifications; Schematics, Software listings and Bills of
Materials; Inspection and Test Reports; and Customer Acceptance sign-off.
Next, you have to accept that change is innevitable and deal with it
properly. The flowchart on my HIDECS page is a simply remembered plan for
dealing with the development of documents and components that assists in
the management of the changes that you will make to your product or
documentation. It can be manually managed with the aid of just four forms
and a register (review form, problem report form, change proposal form and
a work instruction form). The register is used to keep a record of the
existence and the issue status.of each entity.
Once you have those elements in place (and documented as the process you
apply) then you should have little trouble in passing an ISO9001 audit. In
time you could also probably go for the ISO9003-1 audit and get TickIT
certification too. As you build up experience in using these development
processes and they become ingrained as something that you do without having
to think about it too much you should see your CMM level rising.
Of course, things get easier with a slight increase in number of employees.
Sadly, it may get more difficult to ensure consistant application of the
process when your organisation gets considerably larger. That, though, is
down to how good your management are at getting everyone working towards
The above has been nothing more than a brief general overview of
development processes. Much of it is common sense applied consistantly,
properly documented as your process and adhered to (as proven by audit).
I know that there are plenty of people in here and other newsgroups who
have experience of setting up and operating decent development procedures
that will also be able to assist with guidance.
Paul E. Bennett ....................<email:// email@example.com>
I just picked up the following book on the subject and it looks to be
exactly the information I'd been looking for. I'd recommend it to
anyone looking for a good introduction to Process Control
Plant-Wide Process Control
Kelvin T. Erickson, John L. Hedrick
Paul E. Bennett wrote:
Process Automation - A methodology
A paper for automation engineers
This paper describes an approach to the development of highly automated
process systems. The methodology covers all aspects of the life cycle from
requirements definition through implementation to validation, and can be
applied concurrently with the project design engineering on a fast-track
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