aliasxneo
12 hours ago
Part of my career encapsulates a period where I was a PLC programmer, installer, commissioner, and troubleshooter for massive build outs (sky scrapers, data centers, laboratories, factories). Interestingly, this was after years of teaching myself software engineering, eventually participating in large open source projects. The clash of entering the PLC world was _extremely_ harsh.
Let me give an example: I once worked with an integrator who was working on an AHU feeding an extremely critical portion of a datacenter (I was a lead by this point and mostly played babysitter). During certain points of the day you couldn't open the door to this room due to negative pressure because the logic was over-ramping the exhaust fans. As I watched this contractor work, I saw him open his laptop, with Windows on it (because Microsoft has had a death grip on this industry for decades now), and proceed to backup the PLC program into a massive folder with God knows how many other "customer projects" he was carrying around in this thing. He then proceeded to go do some physical checks in the field, came back, and prepared to upload the fixed program. As I watched, I noticed he _grabbed a backup from ANOTHER customer_ and I immediately had to intervene. Who knows what untold damage I saved from that single move.
I tell this story to demonstrate just how far into the dark ages this industry is. I vividly recall coming into the data center for a fortune 50 company, one everyone here would know, and being astonished that they had never heard of Network Attached Storage or RAID and why they might want to consider a disaster recovery plan for their multi-million dollar mechanical plant.
This industry is in _desperate_ need of strong technical help, but unfortunately the "higher ups" tend to be the same people who are "comfortable" with the way thing are and refuse to move. I literally tried for a decade before giving up and moving into software engineering proper.
So, anyways, just imagine the most archaic and barbaric set of IT software, controls, and procedures, dumb that down even further, and you've landed on the infrastructure/teams that operate probably half of critical infrastructure.
amluto
10 hours ago
Another odd observation about the industry. For better or for worse, I inherited a little system controlled by a Fanuc PLC. It had a bug and would occasionally get stuck in a bad state. By some minor miracle, I managed to track down the person who had originally programmed it (now retired and moved out of state), and he emailed me a file and introduced me to his apprentice (who lives in a third state). I found a trial version of the design software, opened the file and found the bug (despite never having seen this style of programming before). Since I had no way to upload a new file (and since it wasn’t clear that uploading it without a matching outdated and not easily available copy of the programming environment would be wise), I convinced the apprentice to come visit while we was nearby for another client. He did not see the bug even when I pointed it out, but I convinced him to make the change and upload the modified file. Now the system works. (He had a Windows laptop with a giant folder of customer files, of course.)
While he was on site, I asked him why there was nothing on the PLC or its enclosure to identify his old boss or give any contact information, and he seemed surprised and told me that no one ever does that. I asked how a new owner is supposed to get support, and he shrugged.
If this thing ever fails, I’ll probably replace it with an Arduino or an ESP32 or something along those lines. Or I’ll just find something off the shelf to replace the entire system.
spauldo
6 hours ago
A microcontroller based solution is rarely a good replacement for a PLC. You can find integrators willing to come out and troubleshoot your device in the field a lot more easily than embedded progammers and vendor support is usually excellent. When your plant is down, that sort of thing matters. PLCs handle harsh environments for decades, whereas with a microcontroller all the thermal issues and power conditioning are all on you. When something fails, it's usually just a matter of pulling a spare module off the shelf and plugging it in.
If that's an old GE 90-30 (a common FANUC system), it's time to replace it. You're currently in that period when the CPU has reached end of life but the modules are still supported and the vendor has an easy upgrade path. Emerson owns the brand now, and can sell you a new unit that'll run your old program with minimal changes. You can call them and get a list of integrators in your area. It'll be pricey, but you won't need to do it again for another quarter century.
polishdude20
10 hours ago
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.
ssl-3
9 hours ago
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.
palmotea
5 hours ago
> 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.
thyristan
8 minutes ago
The PLC is usually in a control cabinet that can be opened by a control cabinet key:
https://www.knipex.de/schaltschrankschluessel?v=2921
Real locks in such systems are rare, sometimes even disallowed. Usually, a lock with a real key is only used to temporarily prevent switching on a machine during maintenance or such.
procarch2019
9 hours ago
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.
ssl-3
8 hours ago
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.
skinfaxi
9 hours ago
> 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?
kotaKat
13 minutes ago
Hospital IT got a call asking where the little binder with the DVDs for the CT scanner were from someone in Radiology 'cause the Siemens tech showed up.
No, we didn't have them, and they told us they last saw them in the back of a cabinet in their own work era.
Turns out those were the unit-specific reload DVDs for half the reconstruction computers and some serial-specific license stuff.
Whoopsie...
ssl-3
8 hours ago
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.
skinfaxi
8 hours ago
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?
lostlogin
6 hours ago
> 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.
ssl-3
8 hours ago
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. :)
coryrc
9 hours ago
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.
aliasxneo
9 hours ago
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.
rurban
3 hours ago
More probably worst use of NixOS. In embedded we care for every single kb, and don't have tolerance for this kind of space waste management system
voakbasda
3 hours ago
Embedded means different things. Personally I have a hard time calling anything that runs Linux as embedded, having cut my teeth on microcontrollers.
hiAndrewQuinn
32 minutes ago
If it's a custom Yocto thing or it involved buildroot at any state of provisioning it gets the moniker "quasi-embedded" to me. Doubly so if it never actually connects to the internet, unlike these water controllers, apparently.
Kim_Bruning
9 hours ago
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.
xtajv
9 hours ago
Same. (Flash drive + busybox edition).
hommelix
5 hours ago
> 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.
KaiserPro
2 hours ago
Nooooope nope nope.
An entire class of controller with really shit security now (as in scanning a network with PLC controllers has a non-trivial chance of rebooting or freezing any number of devices on the network) trained to just plug USB sticks in?
I understand the idea, and its laudable. But the entire model of PLC security needs root and branches overhaul.
steve_adams_86
11 hours ago
Everything you're describing mirrors my experience with remote scientific deployments and lab equipment (wet labs in particular). I support a team which manages dozens of these, and while it's shocking how inefficient and unsafe their practices are, it's similarly shocking how poorly the industry has kept up with or even tried to establish better practices. We get brand new equipment that costs in the realm of $10k for a tiny logger, and the thing is barely capable of remotely managed deployment of version controlled firmware. There are no tools in place to allow proper testing of the firmware unless you have the cash to buy extras and build test harnesses from them. The firmware itself is often in languages that don't have proper testing frameworks, type systems, IDEs, etc.
It's HARD to do the right thing. Dragging and dropping files into proprietary hardware management programs is the de facto standard.
Then you layer on top the unfortunate reality that sometimes electricity does weird stuff, people design weird circuits or wire the wrong components in, and firmware tends to have to deal with non-deterministic inputs a lot more often than, say, an API on the web. It's rough.
The pay is also so much worse in my experience.
analog31
10 hours ago
>>> The pay is also so much worse in my experience.
The result is that anybody who can program well enough to develop software is doing so. Those with any programming skills who remain behind are smart-but-undisciplined programmers, people who have a reason to be in a particular geographic area, too old to think about changing careers, or just plain nuts.
This is what "lack of investment in manufacturing, research, and infrastructure" looks like. Sow what you reap.
Disclosure: I might be one of those people. I came out of grad school in physics research, and programmed an entire plant. Thankfully, that was before it was economical to put every controller on the Internet.
hiAndrewQuinn
35 minutes ago
To me that speaks to a fundamentally incorrect economic structure. I bet PLC programmers could command much higher salaries - at much higher levels of risk - if they held more liability for things going wrong. That, in turn, would spur a lot of economic development around unfucking the field.
On the other hand, markets are generally smarter than I am. Much like how US citizens living in the EU are basically barred from investing in index funds due to two fundamentally incompatible regulatory regimes, there are almost certainly factors here I'm not seeing and wouldn't see without a couple weeks of research and talking to people who have tried and failed as this.
A guy can dream, though.
b40d-48b2-979e
11 hours ago
Not only is the pay worse (like literally half of what you make doing webdev for a corp), but they mandate you be on site at a factory working first shift like you're on the production floor or something, clocking in and out when you're a salary worker. It's an awful culture.
technion
11 hours ago
Im supposed to be doing endpoint work with people working in this field amd basically have to convince compliance they'll need to be local administrators to do their job. They get onsite and dont know what app they'll need until they look at a plc model. They'll download something from a .tw ftp server and its an unsigned executable that absolutely must run as admin to program these things.
It is amazing how much of the sysadmin community just doesnt believe this is a thing you need to work with, everyone insisting its just security people being lazy and so on.
tedd4u
9 hours ago
Oof, that's bad. Iran got burned real bad by Stuxnet, you know they would love to score big with PLC sabotage.
hackernud3s
7 hours ago
I feel like this is, worst case scenario, people drinking bottled water for a week. It's no stuxnet.
tzs
3 hours ago
If a municipal water system was down wouldn't it affect all water to residences, not just drinking water?
Would it be feasible for people to flush their toilets with bottled water for a week?
Kim_Bruning
12 hours ago
Oh I can tell stories too! Meanwhile these guys often have huge amounts of practical experience as electricians or control technicians/engineers to go with their PLC skills, so you can't just say we should get rid of them either.
Breaking into the industrial market is tricky if you don't have connections too. And if you're hired as the PLC programmer, it's sometimes an afterthought AFTER the plant is already built. "What do you mean it'll take another month? The plant is finished, isn't it?".
Oh, and some projects ban "PC"s to begin with. Which sort of excludes any kind of PC programmer. And it sort of even makes sense. A lot of default PC behaviors (especially commercial software), are no longer user-unfriendly but potentially very expensive or even user-lethal when attached to a physical plant.
Sounds like I could learn some things from you (and maybe vice versa). Poke me on the email in my HN profile!
aliasxneo
11 hours ago
Yes, I don't mean to poke fun solely on the integrators. I've seen the "software first" type land in the same role and flail just as hard, if not harder. I recall one individual, who was quite proud of his "beautiful" ladder logic code, after about 3 months of being at the company ended up destroying a $100k+ chiller plant by cavitating all of the pumps because they didn't understand head pressure.
I think that's one of the core difficulties with PLC programming. You have to have strong knowledge on traditional science fields like thermal dynamics, material sciences, fluid mechanics, etc., while also understanding the limitations of a 16 bit floating point integer and why overflowing that can be catastrophic.
amluto
10 hours ago
Sometimes I wonder whether one could design PLC-style software by first expressing the system’s constraints and then writing the actual code and having either (preferably) formal verification that the code will not violate the constraints or (less preferably) enforced assertions that will send the machine into a safe state if the constraints do not hold.
The system I mentioned in my other post controlled some VFDs, and one would occasionally get stuck running at minimum speed forever instead of turning all the off when it should have. Fortunately the only harm done was a stupid waste of power and and nothing was physically damaged. If it had gotten stuck at maximum speed it might have been a different story.
aliasxneo
9 hours ago
A lot of PLC controllers can certainly be unforgiving. I mentioned overflowing a 16 bit float point because that's exactly what happened at a waste water treatment plant I was called out to and the resulting regulatory fiasco that ensued probably cost the company tens if not hundreds of thousands of dollars.
I'd love to see more formal methods come to the field. Part of me says I'll return one day, maybe if AI kicks me out of my software field, but I'd really want to come back at a position I could healthily influence towards safety and correctness.
tedd4u
9 hours ago
Seems like, here in the 21st century, one could reasonably have a model of the plant that tests could be executed against. Anything like that exist?
duckmysick
4 minutes ago
The industry/consulting term is "digital twin". Nothing off the shelf, since every plant is different. Even for a single process it gets complicated really fast. You probably want to track the environment itself too like temperature, humidity, leaks, etc. All the machinery and if they don't have necessary sensors, gotta retrofit them. Oh and human workers too. Stuff like "John Doe pressed a manual override button at 9:25 AM" or "it takes 12 minutes for a forklift operator to move a pallet from zone A to C".
I was involved in a project that made such a twin for a warehouse. It was simpler in theory because there was no manufacturing process. Just moving objects from one place to another. It was still expensive and took a long time. We tracked traffic heatmap but also collected data on and modelled luminosity for safety. On top of that there was a standard warehouse space optimization.
You're going to run into similar problems as with testing and documenting code. Eventually something will change - a process, a machine, a sensor. You have to stay on top of things and update your model too. Otherwise they will drift apart and not be as useful.
aliasxneo
9 hours ago
It can become really complex. As an example, try to predict resonant frequencies on an entire plant full of rotating equipment. It can be done, but it often requires very expensive equipment and skilled technicians capable of using it to profile a plant. And that's just one potential problem you can run into.
Kim_Bruning
9 hours ago
We're often talking about custom plants here, or plants made in very low volume. Making a simulator for that can be prohibitively expensive, since you can't amortize the cost. For particularly important/expensive plants it still sometimes gets done. Though note the simulator might not be able to capture all the nuances of the real world deployment, so it might not be sufficient.
Meanwhile having a separate copy of the plant is also not often viable, once the plants get to any kind of size.
edit: After having 'someone' fact check and remind me: there are quite a number of simulation tools available that can sometimes partially do the work.
elevation
12 hours ago
A colleague of mine transitioned from a senior IC role to manager of a PLC group in the same company. Their methods were just as unsophisticated as you describe, and now he is attempting to evangelize/impose the finer parts of software engineering discipline, such as source control and integration tests (which can be trickier when it requires a hardware test bed.) Bringing some new tools to bear can be a fun job, as long as the team trusts you.
aliasxneo
11 hours ago
Yes, the fortune 50 company I spoke of was running some of the most advanced data centers in the world. There was literally a team of world class IT specialists walking the same corridors as the industrial automation team but they might as well have spoken different languages.
I remember a time where I was beating the drums on security and ended up in a meeting with a senior red team member in the company. This person was absolutely convinced we were not running Windows Server 2008 anywhere in the company (the year was 2019 at the time of that meeting). Needless to say, he was very concerned when I showed him the 50+ servers running it globally, all covering critical infrastructure.
I think eventually Ragnarok will happen and things will improve. I just hope it's not as detrimental as it seems setup to be.
AlotOfReading
11 hours ago
integration tests (which can be trickier when it requires a hardware test bed.)
I use this as a fizzbuzz-type test when I'm interviewing at hardware companies: do they have development hardware in a rack with programmable power supplies and mini-PCs (or similar)? It's a low, low bar for testing, and rules surprisingly many companies.They'll often just have The Guy running manual tests instead.
voakbasda
2 hours ago
Wow. I’d kill for even a guy running my hardware tests. Most of my jobs barely seem to leave time to write the code, before it needs to be scraped off my monitor and poured into the customer’s systems. The ones like you describe with actual hardware labs are a dream when contrasted to those nightmares.
Karrot_Kream
2 hours ago
Does management sell unrealistic deadlines to the vendors that buy your solutions? Are you bound by impossible support contracts? Did the firm just let go of a lot of people and expect everyone to finish work quickly? Curious how the economic/management pressures here work as I abandoned hardware very early in my career (from an internship) for similar reasons.
procarch2019
9 hours ago
Sounds like we have a similar development path. People fail to understand how complex some of these systems can be, especially since you have to have the project to understand what registers/variables are what. Some when Joe the contractor does a job and walks away, you better make sure they give you the project and you store it in a nice safe place.
A good system integrator is worth their weight in gold. Sure they cost more, but getting a whole package turned over to you is worth a million more than 5 years into the lifecycle of a factory when someone wants to make mods/fix a bug/etc and has to reinvent the whole car, not just the wheel.
This industry is always 10-20 years in the past. My company’s preferred vendor only just started supporting virtualization (this is for a DCS) in the past 10 years. I still have to tell my sales people to provide A/V and minimalistic backup and recovery on every project (they essentially cost nothing compared to the rest of any project).
closeparen
8 hours ago
I enjoy watching Cursed Controls on YouTube. For him, the gold standard is a flash drive with the program on it physically hanging out in the control cabinet.
jdw64
2 hours ago
I agree. The problem is this: most companies using PLCs work in isolated networks with internet disconnected, based on confidentiality. There are many difficulties even with using git, because the structure forces you to implement features in a way that makes it hard to separate them. Branching, in particular, doesn't work well with PLC ladder logic—PLC uses proprietary binary formats that make diff tracking impossible, so you're forced into a unified development approach
TacticalCoder
12 hours ago
> So, anyways, just imagine the most archaic and barbaric set of IT software, controls, and procedures, dumb that down even further, and you've landed on the infrastructure/teams that operate probably half of critical infrastructure.
Same with SCADA: just as bad as what you describe.
aliasxneo
11 hours ago
We once reversed engineered Schneider Electric's ION protocol because they wanted to charge us $10k per "seat" to get software that could interact with it directly. We took home a controller and developed a Python program that could intercept and understand the RS-232 comms. We then developed our own system to interact with it. It was all unencrypted. I just did a quick search and it looks like "Secure ION" is now a thing, introduced in the year 2023. Which just proves my point.
voakbasda
2 hours ago
Some of Schneider Electric’s software is a house of cards. Source: I maintained some systems for them a few years back.
Never will they ever get my money again for anything. To wit, I miss the days when APC was a brand that I could trust.
xtajv
8 hours ago
Storytime: Once upon a time, I was a young grasshopper at a small consulting firm at which every employee was issued a Windows machine, our source control system was "\Customers" on C: drive, and our deployment strategy was "putty + copy-paste + hot-reload".
One morning, I heard something terrible while my boss's boss's machine was booting. Something akin to grinding. The thing was angry.
I gave boss^2 a heads-up that his hard drive might be failing, and that he might want to run a S.M.A.R.T. check on the poor thing. I also asked where the backup hard drives were, because I was brand-new and assumed that I just hadn't been issued one yet.
I checked the supply closet, found no hard drives, popped over to the office admin person, and recommended a deal I'd seen on some WD black drives before I realized that the place had gone quiet.
Everyone looked at me like I was from Mars.
Exactly 7 days later, boss^2's hard drive failed. We lost a week of work and had to zero out a 5 days x 3 employees worth of billable hours. We also ended up delivering late.
The client was pissed.
Based on the nasty looks that I got afterwards, it appeared that the standard assumption was that I had tampered with the drive to prove a point. (Um, nope).
I have since learned to ask prospective employers about their backup strategy.
MajorTakeaway
5 hours ago
Nasty looks seems to be the sign of them realizing how you proved them to be incompetent.
Incompetence will cost them their job.
If I had fuck you money I'd just call them incompetent fucks and laugh at them.
tamimio
11 hours ago
The worst part -as I mentioned in another comment few days earlier- is most of the network is ancient, dialup, poor architecture designed by people who barely touched a computer, very old OSes, one utility had windows 3.1 a couple years ago! For them as long as it’s working, don’t touch it, because a downtime is far more costly and it will bring many eyes and attention to them than just sit and hope nothing will happen. Physical security is a major gap too, I have been to many locations where the field server panels are just behind the door, the RTUs are just closed with panel keys, even the whole facility are using some old HID cards that you can unlock in few seconds, this is even in R&D that beyond automation but also in robotic ones.
bitwize
5 hours ago
> This industry is in _desperate_ need of strong technical help, but unfortunately the "higher ups" tend to be the same people who are "comfortable" with the way thing are and refuse to move. I literally tried for a decade before giving up and moving into software engineering proper.
As soon as AI can automate the development and deployment of physical infrastructure and the firmware that drives it, watch how willing to embrace the "cutting edge" those same higher-ups become.
PunchyHamster
an hour ago
I mean it worked fine for 50 years, surely it will work fine for another 50