Pratica di Shadowing: What is a PLC and how does it work? - Impara a parlare inglese con i video
Creazione lezione...
1
You may never have thought about it, because it's one of those easy things to take for granted, but something told that traffic light on your drive to work today when to change from red to green.
2
Similarly, every time you jump in an elevator, something is monitoring those buttons to see what floor you select,
3
and then controlling a motor's ramp and acceleration to get you safely to your destination.
4
The machines responsible for all of these calculations
5
and controls going on in the background
6
and making everyday life possible are called PLCs
7
or programmable logic controllers like this one
8
and in today's video I'm gonna explain to you what they are
9
and how they work basically the entire world of controls
10
and automation and robotics and hobby electronics boil down to inputs and outputs.
11
Inputs are things about your environment like the state of an actuator being extended or retracted or volume, temperature, pressure, flow.
12
Outputs are things that you can control to affect your environment like a motor or a pump or a valve.
13
There's a big need in industry to monitor inputs, make decisions or calculations based on that as well as track things over time like counters,
14
variables, and statuses and then use those decisions to control those outputs.
15
If you've ever tinkered with an Arduino or a Raspberry Pi, you're probably pretty familiar with the basic concepts we just talked about.
16
But in industry you need something that is going to scan those inputs, make decisions about them in the exact same time, in a defined set amount of time,
17
every time, and control outputs very repeatedly and reliably.
18
This is where the PLC or Programmable Logic Controller comes in.
19
If you take one thing away from this video, it's keep this word in mind: determinism.
20
The biggest difference between an industrial PLC or industrial PC
21
and a standard Windows laptop or MacBook is the repeatability and determinism of the code that's running on those machines.
22
Your Windows PC could stop to do something like garbage collection that could create inconsistencies in how it's processing logic.
23
Your PLC will never do that.
24
The way the code is written and compiled
25
and the way the hardware is built is basically a promise that the inputs will be taken
26
of at the very beginning it will process
27
and execute the code in a known and repeatable way
28
and then it will make decisions about the states to control outputs to repeatable in a way
29
that is exactly defined with this comes a bit of syntactic nuance
30
and different programming languages even than conventional computer programming is done in
31
because the entire field
32
and the need for plc's started as a need to replace these complicated intricate relay circuits the most common way you
33
diagram which actually looks more like an electrical circuit than a common programming language.
34
And these PLCs are used absolutely everywhere.
35
Oil and gas, pharmaceutical, food and beverage, paper and wood products.
36
It literally does not matter the industry.
37
You pick one, PLCs are driving it.
38
Theme parks and roller coasters, PLCs are driving them.
39
Elevators and stoplights, PLCs are driving them.
40
The need for a highly repeatable deterministic machine is why the PLC industry manufacturers in this space are Siemens,
41
Allen Bradley, ABB, Modicon, Schneider Electric, as well as some other manufacturers that make them for more focused,
42
specialized purposes, often like Keyence, Mitsubishi, Panasonic, and Bekoff.
43
But that's enough of a high level.
44
Let's go ahead and take a look at some practical examples of how these PLCs work.
45
Okay, for the practical side of today's video, we're going to use a Siemens setup.
46
So I have a basic affordable Siemens PLC and their programming software open.
47
That doesn't matter.
48
What we're talking about is how PLCs work.
49
So regardless of what platform your job or your industry or your career takes you to, the stuff we're about to talk about is platform agnostic.
50
Okay, so I have a brand new PLC program open, there's no code running on my PLC.
51
The only thing I've done in advance is I have two push buttons and an output light.
52
So I have two digital inputs on off inputs, and one on off output we can make reference to while we talk through some of these concepts.
53
And then this main organization block is generated by Siemens and most PLC providers when you create a new PLC program.
54
You can think of this as your main loop.
55
So by default, every PLC has some master thing that it references while it's doing code and logic execution,
56
and that's your main function.
57
So typically, especially in larger PLC programs, you don't put any code inside main.
58
All you do is you want to have execute code.
59
And I'm going to add a new block, call it a function, and I'll just say example function.
60
So this will be very simple.
61
The way main typically works is you would have it execute the function example by calling it here.
62
And then inside example, we can put that code back in there, which is start push button, light turns on, and we'll actually say when the start button is pressed to turn on the light.
63
And when the stop button is pressed, you got it turn off the light.
64
And I'm not going to spend a bunch of time teaching with the ladder logic that I'm writing here, because I have tutorials on ladder programming on the channel already,
65
I really want to focus So to speak briefly about scan time, which is the most important concept in PLC programming,
66
the way a PLC is going to execute is it's going to go to its main organization block
67
and it's going to execute all code from top to bottom, left to right, just like you're reading a book.
68
does anything in example 2 and it processes code in a deterministic way like we said in the intro.
69
It starts by taking a snapshot view of what all the inputs are currently showing
70
and then it executes all of the logic that lives on the PLC
71
and then it makes a decision about whether or not to change the state of outputs based on that.
72
It's actually doing these steps in that defined order
73
It's just doing it at a cycle time that's typically one to two milliseconds for a well -structured small program.
74
So it doesn't even feel like it takes any time at all to the human.
75
And so to show this, I'm going to go ahead and activate this program.
76
We're going to load this onto the PLC really quick.
77
And then I'll show you that the PLC actually tells you how long it's taking to cycle the code.
78
So if I go to example and I go live monitor, I can press the start push button and the light turns on
79
and I can push the stop push button and the light turns off.
80
And to me, it looks instantaneous.
81
It looks like I pushed the button, the light turned on immediately.
82
But that's because if we go to online and diagnostics and go to cycle time, the PLC is telling me, hey, I am running at one millisecond.
83
Okay.
84
I'm doing an entire cycle processing everything I have on my PLC in one second.
85
The longest cycle time it's This is very,
86
very fast for larger projects and complicated projects doing advanced math.
87
It is normal to see these get up there to eight, nine, 10 milliseconds.
88
You actually want to try to keep this number down by writing efficient code.
89
Okay.
90
So every major PLC manufacturer gives you some way like this to see your cycle time.
91
And that's a good indicator of how your code is running, how burdened, how overloaded your PLC is.
92
do all your evaluation logic, and then make decisions about what to do with your outputs,
93
makes sense as an overall structure how PLCs execute code to you.
94
So let's take a little bit more of a look at what the reading top to bottom
95
and left to right actually means practically.
96
Let's go ahead back into example and let's put a few rungs of code in here that sort of conflict
97
light to turn on.
98
And if either push button is not pressed, then I want the light to turn off.
99
And you can maybe see already where the conflict could come in.
100
What about the case where one button is pressed and one button is released?
101
Okay.
102
And so again, the way this code reads, even if you're not familiar with ladder is if start push button, or if stop push button,
103
so my two buttons, if either of those are pressed, turn on the light, but the next rung of code is If not start push button or not stop push button,
104
turn off the light.
105
I'm going to go ahead and put this on my PLC here
106
and we're going to take a look at what that means.
107
Okay, and you can see just when I go online to monitor it, neither of the push buttons are being pressed right now, so the light is off.
108
Now I'm going to push one of the push buttons.
109
What do you think is going to happen to the light?
110
It doesn't turn on, okay?
111
I can verify the light is off in the field, even though the coil right here is lit up green saying, hey, I'm trying to turn the light on.
112
What's also happening is the other button's still not pressed,
113
and so the light is still not turning on because this rung of code is getting executed after this piece of code, which means it's saying, alright,
114
check network 1, oh, I should turn the light on.
115
and not stop and not start. So...
116
If I release both of them, the light goes back off.
117
What's super interesting about this and a really good explanation of what's going on here is
118
if I put this to not and not down here and I put this to on or on up here, flip these around.
119
Now what I've done is I've changed the order of the two rungs exact same code.
120
But now I've said if not start start push button or not stop push button, the light should be off.
121
But then I've said if start push button or stop push button, the light should be off.
122
So now when I hold just one light down and it doesn't matter which push button, excuse me, push button, not light.
123
It doesn't matter which button I hold down, the light turns on in the field.
124
I don't have to hold both of them down.
125
What happened here is we changed the order that those rungs execute in.
126
So we're saying even though these rungs are often in conflict with each other where I have only one button pressed in,
127
then whichever one comes later in my program is going to win.
128
You can use this structure of left to right
129
and top to bottom to your advantage as a programmer if you know what you're doing,
130
but it can also create a lot of headaches where you'll have overwritten outputs if you don't know what you're doing. So frankly,
131
a much cleaner way of structuring your code is find a way to only control outputs from one rung of code.
132
If you want to make it to where start or stop turns the light on, don't have a different rung of code that turns the light off.
133
Find a way to put all of the code of how this code processes top to bottom and left to right.
134
Let's take a look at one more concept in the PLC and that's the idea behind a cyclic interrupt.
135
What if you want something that does not execute as fast as humanly possible that the PLC is continuously evaluating for.
136
So it's usually generally considered pretty cool and useful that the PLC can process something every millisecond.
137
Let's go ahead and delete that function and say we actually want something to be evaluated no faster.
138
than every half second.
139
I can make a new organization block and call it cyclic interrupt.
140
And this is slightly different in Alan Bradley.
141
They do timed function blocks as well, but a little bit different to set up again, not a syntax lesson.
142
And we're going to call this half second.
143
Okay.
144
Thank you.
145
I'm going to go ahead and make this
146
and now I have a new organization block that's only going to be evaluated every 500 milliseconds.
147
So now I can say, let's just simplify and say when the start button is pressed, turn my light on.
148
Alrighty.
149
And so what's pretty cool about this one we're going to see
150
when I download it is I can now click the start push button and the light won't turn on.
151
I'm able to click it fast enough that the light won't always turn on.
152
I let go of the button and there's a time delay before the light turns back off.
153
So I go ahead and click the button.
154
The light does not turn on because I'm clicking it in much less than 500 milliseconds.
155
And it's only evaluating this rung once every 500 milliseconds.
156
But if I hold it down for a half second and the light does turn on, and if I release it,
157
there's a little period of time where the light stays on because it only detects at its next 500 millisecond cliff
158
One important note about these is it doesn't mean
159
that there will always be a half second delay between me pressing the button
160
and the light turning on or always be a half second delay between me releasing the button and the light turning off.
161
Because I could be triggering that button anywhere in that 500 millisecond window.
162
Likewise, I could be releasing the button anywhere in the 500 millisecond window.
163
still look pretty much simultaneous when it turns on, but it could take up to a half a second.
164
Again, there are actual PLC programming tutorials on my channel.
165
You can check those out if you're interested in learning more.
166
The most important thing to retain from this video, so I'm repeating it at the end, is PLCs are deterministic.
167
They give you an exact way to know how your logic is going to behave and behave every time, repeatedly and reliably.
168
They're deterministic, they're They take a snapshot of the inputs, they move it into an image table,
169
they then compute all of their internal logic based on those inputs and variables,
170
and then they make decisions about what outputs to change accordingly based on those inputs in a scan.
171
Hopefully this didn't get too in the weeds and you found it useful
172
and you found it interesting and you want to go to LeMaster Tech, like the video, subscribe to the channel, and learn more about the world of controls and automation.
173
if you have any questions in the comments below, or what you want to see next on the channel.
174
Thanks for watching, and see you next time.
175
Bye.
📺 Stesso Canale
C11
Types of Proximity Sensors! #automation #engineering #science #robotics #electronics
Business EnglishUniversity StudentsWorking Adults
C11
PLC Programming #4: Functions, Function Blocks & Organization Blocks Explained
Business EnglishUniversity StudentsWorking Adults
C11
Going Online with a PLC, Uploading and Downloading Code!
Business EnglishUniversity StudentsWorking Adults
C11
PLC Programming Tutorial - Ladder Logic #3: Math and Calculations
Business EnglishUniversity StudentsWorking Adults
C18
How to Scale Analog Values in PLC Programming!
Business EnglishUniversity StudentsWorking Adults
C16
PLC Programming Tutorial - Ladder Logic #1: Binary & Boolean Operations
Business EnglishUniversity StudentsWorking Adults
C11
PLC Programming #5: User-Defined Data Types (UDTs) Explained
Business EnglishUniversity StudentsWorking Adults
C11
PLC Programming Tutorial - Ladder Logic #2: Timers and Counters
Business EnglishUniversity StudentsWorking Adults
B13
How to Get Started with C# in Visual Studio Code! Full Tutorial for Beginners
Business EnglishUniversity StudentsWorking Adults
C11
PLC State Machines Explained
Business EnglishUniversity StudentsWorking Adults
C1Adding an E-Stop to our Conveyor Build! #plc #automation #engineering #robotics #mechatronics
Business EnglishUniversity StudentsWorking Adults
✨ Video consigliato
C11
162 frasi
Introduction to PLC | Siemens PLC Training Course
Business EnglishUniversity StudentsWorking Adults
C11
40 frasi
The Engineering that Runs the Digital World 🛠️⚙️💻 How do CPUs Work?
Business EnglishUniversity StudentsWorking Adults
C11
149 frasi
Inside a warehouse run by AI robots
Business EnglishUniversity StudentsWorking Adults
C12
48 frasi
Motor Control Methods Explained
Business EnglishUniversity StudentsWorking Adults
C12
64 frasi
P2 什么是机器学习【2024公认最好的 | 吴恩达机器学习 | 教程 | Machine Learning Specialization(超爽中英!)】
Business EnglishUniversity StudentsWorking Adults
C11
7 frasi
Diodes Explained - The basics how diodes work working principle pn junction
Business EnglishUniversity StudentsWorking Adults
C12
12 frasi
Plastic Injection Molding
Business EnglishUniversity StudentsWorking Adults
C11
132 frasi
Video
Business EnglishUniversity StudentsWorking Adults
C11
54 frasi
What is a server? Types of Servers? Virtual server vs Physical server 🖥️🌐
Business EnglishUniversity StudentsWorking Adults
C15
107 frasi
What is NLP? Neuro Linguistic Programming
Business EnglishUniversity StudentsWorking Adults
Contesto & Sfondo
Nel video "What is a PLC and how does it work?", l'oratore introduce il concetto di PLC (Programmable Logic Controller), spiegando come questi dispositivi siano fondamentali nel controllo e automazione industriale. Ogni giorno, elementi come semafori e ascensori utilizzano PLC per monitorare e controllare funzioni cruciali. L'oratore sottolinea l'importanza del "determinismo" nel funzionamento dei PLC rispetto ai computer ordinari, evidenziando come questi macchinari siano progettati per garantire una ripetibilità e precisione elevate in ogni operazione.
Le 5 Frasi Chiave per la Comunicazione Quotidiana
- “Something told that traffic light on your drive to work today when to change from red to green.” – Importante per comprendere come i PLC influenzano la vita quotidiana.
- “This is where the PLC or Programmable Logic Controller comes in.” – Introduzione all'argomento del video.
- “The biggest difference between an industrial PLC and a standard laptop is the repeatability.” – Aiuta a distinguere PLC da altri dispositivi.
- “The entire field started as a need to replace complicated intricate relay circuits.” – Una buona spiegazione del contesto storico e tecnico dei PLC.
- “PLCs are used absolutely everywhere.” – Sottolinea l'importanza e l'onnipresenza dei PLC nell'industria.
Guida passo-passo al Shadowing
Per migliorare le tue abilità di ascolto e pronuncia in inglese, puoi seguire questa guida di shadowing basata sul video. Il shadowing in inglese è una tecnica efficace per affinare la tua comprensione e produzioni verbali.
- Ascolta attentamente: Inizia guardando il video senza pause, prestando attenzione alla pronuncia dell'oratore e alla sua intonazione.
- Ripeti dopo di lui: Accendi i sottotitoli in inglese (se disponibili) e inizia a ripetere le frasi. Questa è una parte cruciale dell'apprendimento: non limitarti a leggere, ascolta e parla.
- Focalizzati sulle frasi chiave: Rivedi le cinque frasi chiave elencate sopra. Queste rappresentano i concetti principali e ripeterle ti aiuterà a consolidare la tua memoria e pronuncia.
- Pratica regolarmente: Sfrutta il video per sessioni di shadow speech quotidiane. Maggiore è la tua esecuzione, migliore sarà la tua fluidità.
- Ripeti finché non ti senti sicuro: Non avere fretta, il shadowing site è un ottimo strumento per migliorare nel tempo.
Imparare l'inglese con YouTube, utilizzando questa tecnica di shadowing, ti aiuterà ad acquisire sicurezza e migliorare le tue capacità comunicative in modo significativo.
La grammatica di questo video
Le strutture che chi parla usa di più, con le parole esatte del video:
| Struttura | Nel video |
|---|---|
| Forma passiva be + participio passato — conta ciò che accade, non chi lo fa | are called · being extended · is written |
| Present perfect have/has + participio passato — un’azione passata che conta ancora adesso | have thought · you've ever tinkered · I've done |
| Frasi relative who / which + frase — un’informazione in più su una persona o una cosa | there, which is · time, which is · code, which means |
Cos'è la tecnica dello Shadowing?
Shadowing è una tecnica di apprendimento delle lingue supportata da studi scientifici, originariamente sviluppata per la formazione dei traduttori professionisti e resa popolare dal poliglotta Dr. Alexander Arguelles. Il metodo è semplice ma potente: ascolti un audio in inglese di madrelingua e lo ripeti immediatamente ad alta voce — come un'ombra che segue il parlante con un ritardo di solo 1–2 secondi. A differenza dell'ascolto passivo o degli esercizi di grammatica, lo shadowing costringe il tuo cervello e i muscoli della bocca a elaborare e riprodurre simultaneamente i modelli di discorso reale. La ricerca dimostra che migliora significativamente la precisione della pronuncia, l'intonazione, il ritmo, il discorso connesso, la comprensione dell'ascolto e la fluidità del parlato — rendendolo uno dei metodi più efficaci per la preparazione alla prova di speaking dell'IELTS e per la comunicazione reale in inglese.