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 common goals.
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.
Try Process Automation - A methodology A paper for automation engineers Overview 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 project.
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 Methodologies.
Steve
Plant-Wide Process Control Kelvin T. Erickson, John L. Hedrick ISBN: 0-471-17835-7
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.