Home automation: PLC vs Arduino Mega + RasPi - current capabilities and costs

Hello.
There used to be a topic https://www.elektroda.pl/rtvforum/topic1452850.html

A lot has changed since then.

Arduino Mega + RasPi give us a lot of possibilities, a lot of inputs/outputs.
Arduino Mega and RasPi themselves are not expensive, modules and sensors for them are not expensive either.

How does PLC vs Arduino and RasPi look like now?

All in all, not much has changed.
Apart from the fact that the prices of Arduino clones have come down, the range of cheap accessories for them has grown.
A lot of ready-made projects have been created on which you can follow, or even take as a ready-made.
It's the same with RPi. The database of software and ready-made projects is already huge. On top of this, several sensible more powerful RPi replacements have been created (BannanaPi, CubieBoard, Odroid).

Nothing has really changed in the PLC. They are more for PRO applications. So prices and availability different.

Depends on what you are betting on.
Huge creative possibilities, cheaply - Arduino.
Certainty of operation - PLC.
Although a well designed and programmed Arduino and RPi will not be inferior to a PLC. And this is where the problem lies

Would you please recommend in your opinion the best site with RPi readymades? There's not much of it on YT, mostly final effects :/

Question for practitioners :

Is it possible to personalise the software to customer requirements in the PLC?
I am thinking of customising e.g. the control panel - buttons, controls, IP monitoring view, connecting this to the LAN and remote control via TCP/IP, cooperation with an alarm system e.g. Satel, etc.

If you use an Arduino/RasPi uC, there's not much of a problem creating a graphical interface for the user, programming is relatively simple (in my opinion) and you can generally make a customised system.

The other issue is, of course, the stability of operation. From previous posts it seems that PLCs are very stable solutions. Does anyone have experience of how this issue is with microprocessors? After all, there is a microprocessor in the PLC too, so what is this stability?

Has anyone done such installations on an Arduino/RasPi?
Please share your experiences in this area.

best regards,
Marcin

Hi

Quote:

Is it possible to personalise the software to customer requirements in the PLC?
I am thinking of customising e.g. the control panel - buttons, controls, IP monitoring view, connecting this to the LAN and remote control via TCP/IP, cooperation with an alarm system e.g. Satel, etc.

You have mixed up some different topics:
A classic PLC does not have an operator panel you have to use dedicated HMI panels, PC software called SCADA, or write your visualisation.
Everything you described can be achieved either on SCADA software or by writing your own application.
When it comes to SCADA you need to pay attention to whether it supports your IP monitoring and alarm systems. Most SCADA allows remote viewing via a web browser.

Quote:

The second issue is, of course, the stability of operation. From previous posts it seems that PLCs are very stable solutions. Does anyone have experience of how this issue is with microprocessors? After all, there is a microprocessor in the PLC too, so what is this stability?

In a PLC there are far fewer places where mistakes can be made due to the fact that the user only enters the algorithm for the part that is important to him without having to deal with interrupt handling, communication, etc.

PLC (Programmable Logic Controller) is a system for which a programme is written from scratch for the customer. It is more commonly used in industry. The controller itself (called a controller in Poland if I am not mistaken) has a microprocessor (yes, and it is based on Ms-Dos!) which is basically a scanner. The programs are considered to be the most stable. Exceptions are government regulations in many countries which require two PLCs to control nuclear power plants, the second PLC as a "backbone" if the first one fails. In home automation it is unlikely to be used due to the cost of the controller itself, to which modules, interfaces and HMI panels must be added. SCADA "supervisory control and data acquisition" is in other words an HMI panel plus the possibility of operating the data stored in memory, which allows us to graphically show how the recordings looked like, e.g. temperature over time or something similar. But SCADA systems for individual controllers themselves are very expensive, unless you use a PC for that, but then there is the problem of the interface between PLC and PC etc. Arduino and RasPi I don't know very well, it seems like a DIY hobby to me but a few panels exist to buy and you can play around with. RasPi is an exception, and I should add that there is a very popular irrigation (sprinkler) system in the world called Open Sprinkler, based on RasPi code. It's probably the most popular irrigation system at the moment, with amazing features and full internet control at a price of $150, and it's based on RasPi. To operate, automate your home, you will need not only a controller but also receivers such as valves, switches, automatic locks, etc. These devices should all work together. These devices should all work with your controller. At the moment I think Z-Wave is one of the most popular systems (wireless interfaces) where the two types of controllers are probably the most popular are: Smartthings and Vera. I am not writing that these are the best but they are certainly the most popular, smartthings is about $99 in the states and vera edge is about $140. I hope these messages will help you.
Sorry without Polish characters but I am writing from my work PC.

Hi,

I myself am thinking about automating my cottage and Z-Wave based solutions are tempting. There is one (or rather the same every time) drawback: the simplest detector, module costs about 250 PLN.
Wireless communication is a definite advantage, although, for example, precise closing of an external roller shutter is difficult - a delay of approx. 0.4sec from pressing the button to stopping the motor.

It is true that z-waves are not cheap. It doesn't look like they're going cheap any time soon because they're introducing new and improved versions which keeps pushing the price up. (Apparently they are the most expensive in Australia). This delay you write about exists, so the controllers only give the command to execute and the individual receivers should control the rest. Remember that each Z-wave module is a receiver, a transmitter and a processor. The system works in such a way that the controller gives the command to perform a function and each receiver should perform it to the end, e.g. if you give the command to close a door lock, the lock performs it by itself from the beginning to the end when the latch in the lock is extended to the end, at the moment when it cannot close it gives information to the controller that the lock is locked and cannot be closed. I don't know how roller shutters work, but if they are only supposed to close at, say, 70%, then the appropriate device should control this. So far the smart home market is in a race to see who will win.

Correction to my post. In the world of Z-Wave controllers worth mentioning is the HomeSeer controller for two reasons, the first because it is very good at programming, has many features, can communicate with Z-Wave devices as well as X10 and Insteon and the fact that it works (at least its hardware) on Arduino if you are interested in that. The disadvantage of this controller is unfortunately the price, where for the most demanding controller you have to pay over $1000 in the states.