Industrial Control System, or ICS, is a general catch all term we use for the control system and associated 1
instrumentation used in industrial production technology. 2
That's quite a mouthful. 3
What it really is, it's a way for us to automate and monitor productions or plants, 4
(and when I say plants, I mean production plants, not flowers) or any other industry component 5
we would have that can work on itself with some autonomy but also need some monitoring. It is often used 6
in power plants, water or water treatment plants, 7
and many parts of the transport industry, even in windmills. Many of the controls there has a low level 8
set of commands or guidelines on how to do their job, 9
and then on the back end, they have a system, that can log into those, and change the parameters. The back end is the 10
SCADA, or Supervisory Control and Data Acquisition. 11
It's a control system architecture, 12
where we use computers, networked data, communication, and graphical user interfaces to, at a high level, supervise and manage 13
the subcomponents. 14
It's basically the control and command center. We can control our devices that are in the field. 15
The Distributed Control Systems and the Programmable Logic Controllers are similar, but have different 16
applications, and which type we choose depends on our need. 17
The Distributed Control System is a computerized control system for a processor or a plant which has autonomous 18
controllers distributed throughout the system. And we'd normally use it 19
if we have more than a few thousand I/O points. The Programmable Logic Controllers are for smaller set ups. 20
If we have less than a couple of thousand I/O points, then we would use the PLC. And it's just an industrial 21
computer that's been ruggedized to handle more abuse, harsher weather, and built specialized for that control 22
or that manufacturing process. 23
Normally we would use one or the other, but there can be a few cases where we'd have PLCs underneath the Distributed 24
Control Systems. 25
Let's look at a practical example. 26
If we we've implementing a SCADA system, we would most likely use the DNP3 protocol, or the third 27
version of the Distributed 28
Network Protocol. For these systems we don't really need a massive amount of data to move back and 29
forth. 30
We just need them to send us the intended data, and the ability for us to change parameters. So many of 31
these systems can run on radio waves or dial up connections, and many of them are not up constantly. 32
They just check in every so often, and if everything is well, they hang up again, and call back later. 33
So regardless of which way the communication is going, either the SCADA master, or other remote terminal 34
unit, RTU, connects to the other. Behind the RTU, 35
we have our intelligent electronic devices. 36
This would be where a PLC or DCS would be. 37
If we look at the example of a windmill, the windmill might be programmed to run if there's enough 38
wind, and shut down if there's not, then it would have a couple of wind sensors to see when it's profitable to 39
start up again. 40
For most intents and purposes, it's a self-contained unit, but you have an either incremental or permanent 41
connection to the RTU, just sending back the information it was programmed to: the wind speeds, 42
how many hours a day it's operational, components checks, things like that, which then can be pushed to 43
the SCADA system, or the SCADA system can pull it whenever it needs the information. 44
And that pretty much is, at a high level, how the SCADA system works. 45
The closer you get to the SCADA system, the smarter it is, but to a large extent the end devices are autonomous.