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Hello everyone, welcome to automation
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community. Today in this video we are
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going to discuss an example in which we
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will be drawing ladder diagram for
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boolean expressions. So let's look at
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Example 12. Y1 is equal to a1 dot b1 +
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c1. And then we have y2 is equal to a2
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b2 dot c2 + d2. So for the first boolean
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expression the output is y and there are
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three inputs a1 b1 and c1. So firstly
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are will be connected in series. So
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there is iron logic gate between A1 and
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B1 and then C1 will be connected in
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and then we have one more boolean
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expression Y2 the output Y2.
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So for output Y2 B and C will be
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connected in series and then T will be
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connected in parallel to B and C and
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then A will be connected in series with
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BC + D. So let's start with the first
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A1 B1 + C1. So A and B will be used as
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normally open contact and will be
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connected in series and then C will be
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connected in parallel. So let's move to
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codices where we will draw a ladder
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diagram for this example. So I will open
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So firstly we need to create a new
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project. Create a new project. Click
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and then we need to name give name to
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this project. Let's say example
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12. And we can also select template as
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standard project. We can also select the
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location where this file will be saved.
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After that you can select device from
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this drop-own list and you can also
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select the PLC programming. So for now
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we are using uh ladder logic diagram.
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Okay. So click on okay.
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So go to PLC programming here double
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click on it. So here we will be drawing
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gladder diagram. So firstly we have a
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dot a1 b1. So we will insert two
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normally open contacts that will be
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connected in series. So this will be a1
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Okay. So, let's delete this one.
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And then this normally open contact will
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After that we will be using uh another
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normally open contact that is plus D1
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sorry plus C1 that will be connected in
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parallel with this. So for that we will
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delete this B1 for now. Let's delete it
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and add a normally open contact here in
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parallel and this will be C1.
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And let's insert here a normally open
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Okay. And after that we will insert a
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coil here. That will be for Y1.
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Okay. So Y1 will turn on when either A1
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and B1 are on or C1 is on. So
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either both of the A1 and B1 should be
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on or only C1 should be on. Okay. So
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Go to online and start simulation.
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And after that we can log in here.
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After that we will start here.
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So as you can see here y1 is off. So
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turn on y1 we will turn on a1. So when I
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will click here when the true appears
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here then go to debug and write values.
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You can see here a1 is true but y1 is uh
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doesn't turn on. So to make it true we
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need to turn on a1 as well as b1. So we
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turn on b1 as well. So let's go to debug
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and write values. And you can see here
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the signal passes through these two
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contacts. As both the contacts A1 and B1
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are true, as a result, this Y1 gets on.
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And then we will turn both the inputs on
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and we will turn on C1. Let's see what
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happens. We'll go to debug and write
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values. You can see here Y1 gets on. So
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either a1 and a b1 both should be on or
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And now we have one more boolean
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expression that is y2 is equal to a2 b2
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dot c2 + d2. So we have four inputs a2
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b2 c2 and d2. So in this case we will
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connect b and c in series and then
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connect d in to parallel with b and c
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and then we will connect a in series.
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So let's move to codices. Okay. So we
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need to insert normally open contact A
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and then this will be A1 uh sorry A2.
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Okay. And this will be B2. And we need
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uh parall to A and B both uh like this.
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a normally open contact in parallel with
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this uh with this A and B. So this is
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Okay. And then we will insert one more
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uh uh sorry contact that is for D2.
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a dot uh so a dot a2 dot b2 plus c2 dot
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d2 and then we will insert a coil
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and this coil will be y2.
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So for y2 to be on d2 should be always
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and this is D2. Okay. So for output Y2
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to be on, A2 should always be on and
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then there is a choice. There is an or
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either C2 and B2 both should be on or D2
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should be on. In short, either C2, B2
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and A2 should be on or D2 and A2 should
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be on. Then only Y2 will be on. So let's
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generate code. Go to online and start
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Okay. So we need to turn on A2.
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Sorry, we'll turn on firstly B2 and C2.
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Let's debug it and write values. You can
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see here Y2 doesn't turn on. So A2
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should be always on. So when we will
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turn on A2, let's go to debug and write
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values. You can see Y2 turns on. And if
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go to debug and write values, Y2 got
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off. Or similarly if I turn on uh if I
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turn on B2 but turn off C2
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then the output will remain off. So
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instead of C2 and B2 we can only uh turn
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on D2. I will turn on D2 and turn off B2
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and turn off also A2. What will happen?
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Y2 will not turn on because A2 is off.
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So A2 should always be on. So that the
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output Y2 will be on. So I will write
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values and you can see here Y2 turn on.
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It was all about this example. Thank you
