Does anybody stamp PLC code?

[BillRobinson]

All,

In your country/state/province/etc, does anybody legally have to stamp/sign-off PLC code? Where I'm from, (Nova Scotia, Canada) anybody can legally write PLC code with no "official" seal of approval. If I were to design a relay logic system that mimicked a PLC routine, a Professional Engineer would have to stamp a drawing and take responsibility for the design.

I think that PLC's have gotten to the point where their complexity and power, can be dangerous and costly and should required a certified, trained, professional to take responsibility of its design. I think this might be a solution to SNK's RANT!

I'm not sure if this is just an Atlantic Canadian thing, so what is the procedure in your area?

Cheers!

 

[PeterW]

Another pinky ring do you mean?

I'm new to Canada and didn't realise about the 'professional engineer' status until I got here.

I can understand the desire, but cannot help to feel it acts as a barrier for decent engineers who have worked their way up through the ranks by being good at what they do.

(Like me, that's why I go against that :nodi.

It blocks the door to honest hard working engineers who have the skill, only allowing University educated engineers to progress.

As I said I can understand the desire to ensure a level of quality, but having that degree does not always guarantee success and by doing so block others who may have the skill.

Really I don't know the answer, I wish I had gone to University when I had the chance many years ago. I gave up my place as a mature student as we had a small child and couldn't find cheap enough place for us all to live, so returned to work.... IF I HAD KNOWN SHE WAS TO DIVORCE ME 5 YEARS LATER!!!

 

[cjd1965]

I would agree that the 'degree' should not be used a barrier. Most of the good guys I know dont have one, and conversley plenty of degee'd guys are not good...

I would say a 'chartered' style thing would work where you have to submit evidence of projects and work you have done to get some recognised qualification, but unless it was world wide it would probably be useless.

I nearly have my degree after many hours of part time study on top of my full time job and family life, but i still favour experience every time.

Cheers

 

[SteinCollector]

Here in the US, this type of sign-off is required in the Pharmaceutical Industry, where a Validation department member must sign-off and a machine when it's commissioned and then anytime code changes are made.

But even then, they are more concerned about the machine operation and making sure there's no way to make bad product without someone's knowledge, rather than making sure code is written properly and documented properly

 

[MASEngr]

Do you require a stamp? That depends on what it's for.

The system I'm working on will be used by the general public. The code requires a P.Eng. stamp, but that's part of the overall electrical system. You can't practice Engineering in Canada unless you're a P.Eng. or you're supervised by one. To do otherwise is unlawful. It's a restricted trade. The End.

Some provinces are starting to regulate Software Engineering, and my Alma Mater offers a B.Eng. in Software. APEG-BC has special guidelines for Professional Software Engineers. I'm certain that PLC code would fall under that SE umbrella.

Now, here's where they split the hairs - most of the time, when software fails, it's merely inconvenient; it's neither dangerous nor deadly. If I can't check my friend requests on Facebook today because there's a vunerability in Flash, who cares? If I have to wait until 3pm to check my bank balance (or go to the branch) is that a public protection issue? No. If my embedded code running a VHF transmitter for tracking down people who have wandered off into the woods fails, is that a problem? Yes, because there's a very real chance that someone will die if that code fails. You bet your ring fingers that a P.Eng. supervised that code.

If you're building something in a plant for trained workers, then you may not require a stamp. Especially if - and if you've designed your system correctly, this is true - the PLC can do whatever the heck it wants to and the safeties will keep the workers and equipment safe. The system I've got here only lets the PLC play in its little sandbox. If the code goes to nowhere, then the completely separate systems will keep the end users safe. This system is a little special, though. It requires stamps from a Structural, Mechanical, and Electrical P.Eng. PLUS an inspection from a Federal Elevator inspector. (Even though it's not an elevator, it's still a chair lift on Federal Land.)

Don't forget that your system doesn't end when the PLC does. All that wiring has to be approved, and those safety mechanisms have to follow the lastest versions of the code you're under. Most of them are quite specific about how to keep the computer / PLC / software control safe even when it fails.

As for requiring a degree, that's not always the case. Depending on your experience, you may not require it. You would require a significant amount of experience to compensate. Check with your local Association.

 

[PeterW]

I've worked a few times in the Nuclear industry which I was told is run along similar lines to Pharmaceutical.

There we had to have any changes checked and signed and checked and counter-signed etc etc... usually by peers and management.

 

[curlyandshemp]

All,

In your country/state/province/etc, does anybody legally have to stamp/sign-off PLC code? Where I'm from, (Nova Scotia, Canada) anybody can legally write PLC code with no "official" seal of approval. If I were to design a relay logic system that mimicked a PLC routine, a Professional Engineer would have to stamp a drawing and take responsibility for the design.

I think that PLC's have gotten to the point where their complexity and power, can be dangerous and costly and should required a certified, trained, professional to take responsibility of its design. I think this might be a solution to SNK's RANT!

I'm not sure if this is just an Atlantic Canadian thing, so what is the procedure in your area?

Cheers!

In the dairy industry, if PLC controls the 'legal valves', then the PLC operations are certified by a CFIA inspector. The operations of the valves are compared to a standard Flow Logic diagram as to how the vlaves should operate.

The legal PLC must be in an enclosure that can have a government seal attached to prove that the controls enclosure has not been opened since approval

 

[Oakley]

The legal PLC must be in an enclosure that can have a government seal attached to prove that the controls enclosure has not been opened since approval

Hmmm. What do you do if you have maintenance required? Like say a battery replacement? Or cabinet cleaning? Or code backup?

Do you have connectors on the outside of the cabinet for communications? What about Arc-Flash requirements?

Gosh, so many questions, such little time. Just curious.

 

[curlyandshemp]

Hmmm. What do you do if you have maintenance required? Like say a battery replacement? Or cabinet cleaning? Or code backup?

Do you have connectors on the outside of the cabinet for communications? What about Arc-Flash requirements?

Gosh, so many questions, such little time. Just curious.

same situation as if a gas pump @ a gas station fails. Inspector must come in to reseal after repairs.
Also, no means of any external communications are allowed, that also means no HMIs. The legal PLC is supposed to be a 'black box'.