hello guys today I am teaching programmable logic controller PLC in industry the wide application of PLC in all the machines so we'll see there some basics of PLC and some program programs of PLC the first of all the PLC is the thing but a mini computer is a black box so PLC is a black box here there are some inputs some inputs and here there are some office so usually standard way the input is i1 i2 i3 and i-4 and outputs are q1 q2 q3 and q4 so on depends on applications sometimes two inputs four outputs sometimes hundred inputs 50 outputs depend upon the applications we can choose the PLC so PLC is a small computer in the PLC there is a memory this is called input model this is called output model and PLC is required 24 volt DC and 0 volt nothing so this PNC will connect to the PC otherwise directly we can correct to the Machine sensor suppose we first of all we study D programs now what are the basics of PLC so first here there are two types of the programmable logic controller the language is for the programming's are four times the basically we are learning there is a very powerful and widely used is a lot of programming so P&C ladder programming plc ladder programming ok functional block diagram is a one more language ok but this is the plc ladder programming widely used in the industry here in the plc ladder programming only we are using some basics this is called normally open switch normally open switch this is called normally closed to switch first of all we try to understand you know and ENC yellow means what already is normally open whenever I press this then the current will flow this side whenever I press this the current will stall so presently the current is flowing like this and currently the current is stops here when it is on you know when it is on the current is flowing when it is off stop here when it is on on and off and here also on and off when off when n o is on that it is closes off means the present position here reverse when when the current is flowing then it is off when the current is not flowing it is on exactly it is a reverse of you know switch so we will try to write a small program on plc ladder by using yellow MC and this is the output symbol this is called output symbol in a PLC ladder program these are called inputs these are called inputs okay for example for example I draw a program the question is like this light a ladder BMC ladder program for and and all logic you know i handing it in or gate so first of all and write for and the logic you know that in the hand logic so how many inputs it will be two three four when all the inputs are on then only the output is on if any one input is off then the output is also off like suppose example 2 1 1 1 1 1 0 1 0 sorry 0 1 0 0 0 0 so in the and Razzak the ladder programming like this suppose there are two switch both are both are what normally open suppose this is the in one in two out out output may be bulb output will be pumped out we will turbine output may be relay output may be anything input other switch okay whenever here if i this is on and this is off still is output is off if both we close all means both will close like this then the output is on so this is the and gate the application of fan gate in the press if the both the input buttons if you press by both the hands then only the press we start okay sometimes the both the inputs are spring rate a push button our toggle switch there is a later case and second one second one is the second one is the or gate or gate in our game anyone input is on the output is home suppose for example there are two inputs the input 1 and Baddeley I'll take input 2 also then this is the output so output may be anything on the pipe I can give any name we or C whatever so here 24 volt here 0 the current is flowing from this rail to this rail these are odd range and these are quadrants this is a one ton this second one now input one is on that current is going from this point to this point bulb is on even input 2 is off no problem when input 2 is on the current is flowing from this the output is on if both are on the output is on if both are off the output is of means in a nor gate any one input is on the output is on this is the latter programming for arcade next one next one I'll apply this PLC diagram to the our pneumatic system in the new metric system for example the question will ask like this right a PLC ladder programming for pneumatics circuit especially for for a plus and a minus so first there are two parts the first one is the pneumatic circuit in a pneumatic circuit first I will take a double-acting cylinder it's called double it to insulin then I will take the Phi by 2 Phi by 2 whoa solid idols both the side there is a soul around this is symbol for soul aligned this is called a plus this is called a minus there are two sensors I'm using these two are the magnetic sensor because the piston is also magnetic so that the proximity sensor or a real switch or the magnetic sensors anyone so for this I need a compressor so this is symbol of compressor so for a compressor there is a need of motor then here I am usually attaching for a second position because in the second portion the piston will retract it will retract here these are called muffle as two mufflers porpoise now presently in the air is one in this direction and it is coming from this direction it goes to the atmosphere okay fine yeah and therefore a unit is required okay so now this is called a figure this is called what pneumatic circuit this is called pneumatic circular now I'll draw the electric circuit special plc ladder to run this pneumatic - PLC and specially I'll draw the programming part the programming part is like this when when the piston is at s1 when the piston is at s1 j+ should on and a blush should on the air will move through this position it goes to this side piston side the piston will move this side right side when it reaches to s2 and immediately what happened a plus should be off but this position should be remain so on when it moves to a stone then the signal goes to a - a - should on then the air moves this side they there is a piston rod side so the piston has to most to the left so like this continuously it should to and fro motion continuously when it reaches to s2 it comes back when it comes to s 1 it goes to s 2 so it is automatically to and fro motion of piston okay now ladder programming in the ladder programming I draw like this there are two rails there are two rails the first one the condition is that when it is at the s1 s1 is my input now s1 is my input when it is at s1 and it is at s1 a plus should on this output this output k plus should on this is a logic programmable logic controller lossy case when it is at s1 the a plus should off so that the piston will move from this position cook this portion when it moves to yes - then a - shoot on a - room so when reaches to s2 m aneesa's oh then it comes to the s-1 it goes to s - automatically this is called what figure plc ladder programming if this logic is right then we oughta field in the pmc then plc the hardware of the plc connected to here here and here here then exactly it is working this is the what plc ladder programming for pneumatic circuit for a plus and a minus okay now I'll go for okay so I'll move to the next lecture okay I'll stop the first lecture here