The best thing they could do to new PLC's would be to have the src code live alongside the firmware inside. So any new person would be able to open it and reason about it.
The best thing they could do to new PLC's would be to have the src code live alongside the firmware inside. So any new person would be able to open it and reason about it.
You mean like, just hang a thumb drive on a lanyard inside of the cabinet -- with source code and such?
That will probably just disappear. Maybe with good intention or maybe with bad, but it's probably gone either way.
If it doesn't disappear, then it's hanging right there for any of the competitors to use. That's a problem for the original installer's ongoing employment.
And if it includes the programming software, then that lets Joe (from over in shipping) have a go at rejiggering the packaging machine. That's a problem for whoever has to pay someone with a clue to show up and fix it.
> You mean like, just hang a thumb drive on a lanyard inside of the cabinet -- with source code and such?
This guy is very happy when someone literally does that: https://www.youtube.com/@Cursed_Controls (great channel btw), because usually he has to deal with worse.
> And if it includes the programming software, then that lets Joe (from over in shipping) have a go at rejiggering the packaging machine. That's a problem for whoever has to pay someone with a clue to show up and fix it.
You'd think Joe from shipping wouldn't be given a key to the cabinet with the PLC.
Even more so, if it’s just there you’re making it easy for the customer to find someone bidding less to execute new projects. Guess who they’re calling if they don’t have the plc project (or don’t understand they need it). Job security.
Plus, yea, someone could really make a mess even if they have the best intention. A guy from my company almost uploaded the wrong program to a large bioreactor. At best it would have made the bioreactor just unusable until corrected. At worst it could have broken the equipment or caused a safety issue. This guy had been around the block a few times too. Luckily someone noticed before it was too late.
I don't get into PLCs, per se, but I've done some stuff with other building-scale gear.
Like: We took care of the centralized controls for the inmate portion of a jail that was built in the 1980s. We rejiggered the controls for that whole jail back around 2010 or so with new kit and had been taking care of it since then.
All the wiring for all of the individual doors and intercoms was documented in one old 3-ring binder. (There were probably 3 copies originally -- for the architect, the maintenance room, and the equipment room, but just 1 remained and it had hand-written notes.)
One day, around 2020-ish, they called us because the book was missing. I didn't have it (I never once left the equipment room with it), and the co-workers who had been there insisted that they didn't have it either.
As time passed, we'd get occasional phone calls of "Hey, we really could use the book for our building back if you guys ever find it." They weren't angry calls, but sheesh: That book had real value and getting stuff done without it was difficult. So every time when they'd call again, I'd ask around our shop -- again -- if it had turned up anywhere.
And then, finally: One of our guys cleaned out his truck and found it. He must have taken the book out to look at and have a smoke about some problem or other, and then it just stayed in his truck. For years.
This shit happens. People are imperfect and sometimes we screw stuff up.
> If it doesn't disappear, then it's hanging right there for any of the competitors to use. That's a problem for the original installer's ongoing employment.
Is that really an issue? Do PLC vendors have concerns about other vendors turning up and yanking USB drives out of critical infrastructure with reckless abandon? Do the facilities themselves see no issue with potential vendors yanking operational utilities out of their systems while they are running?
Eh?
It's just a thumb drive, on a lanyard, hanging in a cabinet. It's not like it has guards posted. :)
Maybe Joe (from shipping) took it back to his desk to have a squiz at it and try to passively learn something new during some otherwise-downtime and never returned it -- years ago. That cabinet is in his area, so he has the key.
Maybe Tim (the plant electrician) borrowed it to get something else done, and it unintentionally disappeared somewhere along the way. Tim has all of the keys for all of the things.
Maybe Emily (the ubergeek who prides herself on being able to code her way out of a mess on any system) had it in her office before she got hit by a car and lost the ability to communicate with polysyllabic words. She borrowed Joe's cabinet key after he mentioned an issue.
Either way, it was just a thumb drive that had been inside of the cabinet, and now it is gone.
Things like thumb drives physically connected to cabinets can just disappear in your environment with no followup whatsoever? And that's regular, expected, and desired?
> Things like thumb drives physically connected to cabinets can just disappear in your environment with no followup whatsoever?
Yes. I follow up. No one ever knows.
> And that's regular,
Yes
> expected
Yes
> and desired?
No.
So they conduct a formal investigation. Top Men descend upon the facility to figure out whether we blame Joe, or Tim, or Emily. Heads roll.
And the thumb drive is still gone, isn't it?
---
No, it's not regular. It's not desired.
Does shit never go wrong in your world? If not, then: Perhaps you should start expecting it to. :)
> The best thing they could do to new PLC's would be to have the src code live alongside the firmware inside. So any new person would be able to open it and reason about it.
This is already the case. Some PLC allows you to store and retrieve the source code of the programmed directly in the flash of the PLC. Sometimes this feature is behind a higher access level or password.
Relatedly, I made an embedded product. I built a live CD (yes this was a while ago) for my employer with the entire development environment. As long as you can find an x86 machine with CD-ROM you could build, compile, test, and program using the exact environment I did twenty years ago.
Maybe today I'd do micropython on ESP32. Download text file from device, edit, upload back on.
There's at least one customer out there who has an RPi with NixOS on it from me. Probably still works to this day. It was the best use of NixOS I think I've ever found.
I've switched up to NUC-ish hardware which WAS cheap until recently. All the components just a bit higher quality than the lowest-bidder you get on the Pi. Run nixos on that and you've got a really solid platform.
Same. (Flash drive + busybox edition).