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Comment by burpingtree | Hacker News Reader

Is it really more expensive to not connect a water treatment plant to the internet? I can imagine the vendor selling that idea but I struggle to come up with how that could make a water treatment plant cheaper to operate.

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Yes. Without a remote system you must have a real person check levels, pumps, pressures, and many other devices thus be present. This person must be trained and you will likely need a backup as well.

If not a person you need more redundancies built in. Bigger tanks, multiple backup systems. When items start failing you need them to be shutoff in a timely manner. Water pumps at these facilities are in the 50-100k range. When it starts failing you want to know.

Think of it like driving a car and it starts making funny noises. The longer you wait to fix it the more it costs.

Why that drastic, checking system state (telemetry) can be done using 'data diode' style networking - one network just broadcasting sensor data, other network allows changing parameters and 3rd one allows allows software upgrades and so on.

You can be very defensive and design any remote sensing controller to act as two systems - one management cpu only does data routing (no other connection than administrative tasks), sensor cpu works only with sensors. As bonus you can have management cpu act as active firewall.

Main problem it is necessary to have in house expertise (hw, fw and process knowing) which in making company lean are optimized first and outsourcing custom solutions suddenly too expensive.

Or you can just slap a lot of Windows XP boxes with closed source control software and remote access software and let the central team do it. Which will be a bit cheaper

Surely it isn't impossible to devise one-way data flows that provably work for remote sensing? And yeah then you have to send somebody to fix stuff if something is off..

Like something that would work but not not scale would be one computer writing data to an updating qr code and another reading it. Surely something like that can be made (and probably already exists?) on the cable level?

Just go dumber

Set up a monitor with the data values you need to monitor

Point a camera at that monitor.

Camera feed is remote accessible. Control software is not.

Want alarming? There's systems designed specifically to send texts or make phone calls when signaled electronically.

This smells wrong to me. You already have people working at the water treatment plant. You don’t need it connected to the internet?

Most water treatment works are unmanned most of the time. You don't need 24/7 staffing or even close.

But more to the point, a modern water network has a huge number of nodes. If you can't centrally aggregate and control in a control room the costs and complexity explode, probably also the error rate.

Even if you demand a full air gap, the solution here can't be to get rid of computers or networks. They are much, much too valuable. Luckily industrial control is full of very low hanging fruits.

There is lots of infrastructure related to water that doesn't have someone physically there 24/7 as it would not be feasible to do so as 99.9% of the time there is nothing to do. So you need some sort of remote alarm system that can be monitored.

at least disconnect the poison valve

The expense usually comes in operations. By connecting the water treatment plant to the Internet and making it remotely operable, you can have one guy who sits in an office and is responsible for overseeing the water quality at many different treatment plants. If everything is local, you need one guy on site at each different plant. People are expensive, software is cheap.

Of course, by making it remotely operable, that one guy could be replaced with a guy in Russia who's job is to poison everyone.

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