Shadowing Practice: PLC Programming Tutorial - Ladder Logic #3: Math and Calculations - Learn English Speaking with YouTube

⏸ Paused

Hello and welcome back to Lemaster Tech

Speed:

184 sentences

If sentences are too short or too long, click Edit to adjust them.

Hello and welcome back to Lemaster Tech

and in today's video we'll be continuing our series on the basics of PLC programming in ladder logic programming language.

Today we'll focus on basic math operations including multiplication, division, addition, subtraction, and then we'll talk about the calculate block which combines many of these operations together.

If you like the content in this video

and you've been finding these tutorials helpful please consider leaving a like on the video

and subscribing to the channel it helps me out a ton.

Now let's get into this tutorial.

okay so for today's video i've just gone ahead

and made some empty integer tags in my plc

so we're gonna use integers we don't need reels or floats but the math that we're doing in today's video,

you could make these floats or decimal values and they will still work.

We're just going to use integers today to keep it simple.

So let's go into our ladder tutorials binary block.

It doesn't matter if you still have some of the binary code from past videos in there.

Today, we're going to start from scratch.

Concepts covered in these videos are applicable to generally every PLC programming platform in the world.

Ladder diagram.

These are standard blocks.

Um...

So today we're going to talk about when you hit an empty block, pretty much every PLC programming software has some version of all the basic mathematical operations.

They have an add block.

They have a subtract block.

They have a...

division block and a multiplication block And a cool thing about Tia, most platforms have some version of this.

But if you have a block, it's very easy to change in between one and the other.

To make this a little bit more readable, I'll put add and subtract up top.

and I'll put multiply and divide.

in the bottom.

And just to talk about the sort of the variables that you're seeing on these blocks, um you're seeing input one and input two and then an output

The easiest thing we can do to showcase these working is use one variable like my in zero.

and put a hard -coded value in input 2.

and then put a new integer in the output here and say myInt1.

So what this should do is say one plus two goes into the output.

Now let's go ahead and set all of these up at once because this isn't really the super interesting part.

I'm gonna just sort of jump ahead to where I have my values added into each block

so you don't have to watch it.

Okay, and you don't have to use the same, actually it's probably better if I don't, you don't have to use the same constant for every block just to be clear.

This is just me entering a number.

And you could enter another variable in here too.

If you're doing something dynamic scaling or checking states of sequence steps or anything else like that, this could also be a variable and you see addition

and multiplication are ones where they're also okay with you adding multiple operands.

So obviously to do addition you have to add at least two things together.

Same with multiplication.

But you could do a long string of multiple values, addition and multiplication on these blocks.

It isn't there for subtraction and division because the order matters, and they can't necessarily tell if you want to divide this by this by this by this,

or subtract this by this by this by this in what order.

But addition and multiplication you can.

And in just a minute we'll talk about a more complicated block that does let you combine all of these functions.

But let's go ahead and download to the PLC just to showcase these four simple mathematical blocks.

And we'll go ahead and write some values to these integers and we'll see what happens to the outputs.

Okay.

So here we see my in zero currently set to zero.

If I change it to 50, you see my int one is just 50 plus 10.

It's 60.

If I change this to...

75 My int 1 is 85.

So the output is simply the addition of 1 plus 2.

A little bit different over here.

If you look at the subtract block, it's 1 minus 2.

A little bit different, but not really.

And if you do 20 minus 8, it's 12.

Okay, so input 1 minus input 2 goes into input 3.

Multiplication, 32 times 6 is 195.

Pretty straightforward.

You know, five times six should be 30.

So there you go.

Division zero divided by four zero.

Let's make it something more interesting than zero like 26 And you see something interesting now with Tia Portal.

If you're dividing an integer by an integer and putting it in an integer value, it will still allow that, but it's going to give you the nearest integer value.

And so 26 divided by four.

is obviously 6 .5.

And if we went to 27, you're getting 6 .75, but you see it's doing floor division.

It's rounding down.

There's one block I wasn't necessarily going to cover because it's a little less common here, but the modulus block is sort of the fifth math block.

And if we took this input six and we still put four down here, and we put it in a new integer value, my in eight, let's say,

and we divide or download.

There we go.

You can see that if you're using integer values because booleans or sorry floats decimal values use up more memory.

Sometimes you do just want to use an integer and know what the remainder is.

That's what the mod block is.

Modulus is the remainder of a division system.

So 27 divided by four, where you want the integer value will round down to six, and so will 26 and so will 25.

but what's changing is the remainder, so you can get the remainder separately using this modulus block.

Okay?

So there's addition, subtraction, multiplication, division, and modulus.

Alright, so that's a lot of simple math pretty fast.

One, maybe it's useful, maybe not to you.

One useful thing to call out is you can actually put the same input on the left side and the right side.

of a math block so if you're doing some sort of transformation on one line of a value

like scaling and you can say like, oh, okay, the integer that I currently have plus 10, and then store it in the same variable name.

There's really no good reason to do that, but technically it's still valid code.

So let's look at a real world scenario really quick where we combine a couple of these

and to create a Celsius to Fahrenheit or Fahrenheit to Celsius converter, right?

You can take a you know your initial value times nine and you can store that in...

my in one

And then you can take my int 1 as the output from there

and store it as the input from 2 and then say divide by 5.

Put that in my int 2.

And then you can add my int2. To 32.

100

I moved it.

101

I didn't copy it.

102

There we go.

103

And that obviously you can store in my int.

104

Three.

105

So let's go ahead and download that to the PLC.

106

I'm sure all those intermediates had values, but they'll get overwritten.

107

Oh, this is Celsius to Fahrenheit.

108

75 Celsius is quite hot.

109

30 Celsius.

110

Is 86 Fahrenheit.

111

Okay, that math checks out.

112

So we built a Celsius to Fahrenheit converter.

113

I put it in my notes backwards.

114

Let's actually go ahead real quick and do the same thing.

115

Let's do Fahrenheit to Celsius, see it in reverse.

116

Okay, and I went ahead and spared you the pain of having to watch me type it all out.

117

But here we can see Fahrenheit to Celsius is the same formula but in reverse.

118

It's taking, you know, some number subtracting 32 out.

119

and then multiplying by 5, dividing by 10.

120

So in this case, rather than 30, let's just see it in reverse.

121

If it's 86 degrees Fahrenheit, it's 30 Celsius.

122

This makes sense because we're seeing the same formula in reverse.

123

So let's see what our Fahrenheit to Celsius converter says.

124

If it's a brisk autumn day and it's 60 degrees, that's 15 celsius and you know the math should check out

125

because if we go and make this 15 we should get OK, 59.

126

But that's actually an interesting one because you're seeing the two different types of rounding going on by using exclusively integer values, because if these were all reals,

127

they would obviously be to the decimal precision the exact same number um

128

but that's actually cool you're seeing a symptom of using integers for your math

129

but this is still a functioning celsius to fahrenheit and fahrenheit to celsius converter However, you may be looking at this and saying this looks kind of stupid.

130

I need six integers to be able to do this math.

131

You know, I have to

132

output to an integer value that then goes

133

and becomes the input of another block on every one of these blocks

134

and no you don't that's actually where a far more useful

135

block for doing multi -step calculations like this comes in

136

and in Siemens it's called calculate in Allen Bradley Rockwell it's called compute so you type a CPT in

137

Pretty much every Allen Bradley instruction has like a three letter or four letter

138

abbreviation and CPT is the version of this that you use in Allen Bradley.

139

I actually think the compute block in Rockwell is a little bit more intuitive than the calculate block in Siemens

140

but They do functionally the same thing.

141

And what's cool about this is I can take that same input, my int 0, which is going to be our Celsius input,

142

and then I can store it to a new output that will be our secondary check.

143

So my int 4, if we do this calculation right, should be the same as my in three because we're going to attempt to multiply by nine divide by 5,

144

and add 32, all in this one block.

145

So we're going to try to multiply by nine, divide by 5, and then add 32.

146

all to my int zero.

147

by tap double clicking this output or whatever your PLC IDE version of editing this is.

148

And the output we reference those input variables in defining our output function.

149

So we just come in here and we say, input one times input two,

150

so multiply by nine, divided by input 3 divided by 5 and then plus input 4.

151

So add 32.

152

Okay?

153

And I'm quite confident this is going to work, but let's go ahead and do the reverse version of it too so you can

154

We can just get both of them knocked out at the same time.

155

So we'll use that my int 5 as the input.

156

And what's the next unused one?

157

We'll use my int 9 as the output for this one.

158

And then the only thing different here is we want to subtract by 32, multiply by 5, and divide by 9.

159

I'll just keep them in that order we want to use them here.

160

And this function is going to be...

161

little different it's gonna be input 1 minus input 2 Fortunately, compute blocks and calculate blocks respect PEMDAS.

162

It respects the order of operations, to put it more clearly.

163

So we're going to use those parentheses to say do the subtraction first, and then multiply by input 3 and divide by input 4.

164

Uh, that was, there we go.

165

I put a space in the wrong spot.

166

Okay, so this is saying, you know, the input minus 32 times 5 divided by 9.

167

Okay, so if we did our math correctly and I'm something of a math whiz, Let's go ahead and download.

168

So we did the kind of step show each step using each block one at a time

169

and we have 15 converts up to 59 and then we have 60 converts down to 15.

170

We see the same thing happening here.

171

So if we say Celsius 22 degrees.

172

71 degrees Fahrenheit well let's say if we have 72 degrees Fahrenheit it converts down to 22 degrees Celsius.

173

So 75, 23, yeah I guess I saw that coming.

174

19 would convert up to 66.

175

Okay, so this is a pretty solid basic introduction to math and simple Mathematical operations in ladder programming for Siemens.

176

And so we'll probably do an advanced math video at some point in the future, but those come up far less frequently than the ones we covered today.

177

Hopefully you found this useful.

178

Hopefully you've been enjoying the series.

179

If there's a specific concept you want to see covered in the video.

180

in a video, be sure to let me know about in the comments below.

181

As always, thank you for watching.

182

Don't forget to like the video, subscribe to the channel, and see you next time.

183

Thanks.

184

Bye.

What is the Shadowing Technique?

Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.

ShadowingEnglish.com – English Shadowing Practice

Speak English fluently using the Shadowing technique. Listen to native YouTube videos, repeat sentence by sentence, and build real pronunciation and fluency — used by IELTS learners worldwide.

Shadowing Practice: PLC Programming Tutorial - Ladder Logic #3: Math and Calculations - Learn English Speaking with YouTube

About This Lesson

Key Vocabulary & Phrases

Practice Tips

What is the Shadowing Technique?

Shadowing Practice: PLC Programming Tutorial - Ladder Logic #3: Math and Calculations - Learn English Speaking with YouTube

Download App

About This Lesson

Key Vocabulary & Phrases

Practice Tips

What is the Shadowing Technique?