I’m an electrician who joined a company who does a lot of industrial work bringing power to tons of motors, switch gears, smart panels and a lot of controls going back to multiple PLC cabinets. We have one guy who does the programming and another who does controls. We have tons of electricians none of which understand controls. You just brought me into the game. Being the first to understand both worlds in this company. I Might not be a professional in controls but I sure understand it now. Thank you my friend
This professor has done a great service to learner's. Although I am a programmer, I could never have given such clear explanation. Thank you Sir, Keep up the good work.
You can't ask for a better video tutorial. I understood everything you explained. i had to go back a few times, but I eventually got it. The pictures and the way everything was set up was perfect. Great video.
This video is top notch for training and educating. Thank you very much for taking the time to put these together. Thanks for sharing and doing such a great job of narrating and educating our technicians!
I am about halfway through this video, after having watched part 1. I have basically no PLC background, an amateur electrical background, and lots of programming background. I actually understand now how an input module isolates field wiring from PLC wiring. It became an epiphany as to how the whole process automation scheme works on a grand scale. When the normally open contact to the light bulb above my head became True, I was going "Wow. Wow!" My wife quirked an eyebrow at me. I said, "Honey, you don't understand. This transcends any religious experience!" Hyperbole, of course, and some of you more advanced people may sneer, but I am ever grateful to the folks at plcprofessor for having the heart to produce this video and the balls to make it freely available.
Taking PLC fundamentals at college, his video has thought me more than what I've learned in the entire semester !! Way to go professor, now I need to learn how to program
At my 57 years I went again to school to get my electrician carta proffesional II, I have a solar energy company and with your help I will pass the test next week. It is so nice explained, thank you Sir. Greetings from portugal
Excellent. This refresher has been exactly what I needed in a short but detailed package. You may count yourself amongst the "good guys" for doing this!
ok professor, i watched this video, and its starting to make sense now about the true if on, false if off, or true if off, false if on, your great, not knocking my instructor, but i can really understand you alot better than i can him, man your a godsend to me, and i may just have a chance at passing this class
Thank you for the excellent teaching. This was very clear thanks to your 'foundations first' approach. The progression from relay basics to the more advanced PLC hardware really made this very understandable. You are a gifted teacher.
Thank you so much.. I am beginning a job in controls and have absolutely no experience. These videos have enabled me to learn the PLC fundamentals without going to school and better yet for free! Your dedication to online learning is much appreciated :) !!! Thank you
plcprof, Again, this is a great video. I am reviewing these, but learning a lot in the process. I like what you have done and have encouraged others in my group to watch these also. Keep it going.
Really helps those of us with a pre-existing knowledge of electricity and schematics. A great started video. I'd like to see more of his explanation videos of more in depth programming.
thanks so much for putting the time and effort into something so powerful and beneficial such as plc progamming.I'm in the process of taking my PLC classes and th ese videos really helped me a lot. thanks professor and keep up the good work. you ROCKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK.
i vaiue all the information that your teaching me. Ive shared you site with my friends and hope they support you. With what your teaching me im sure i get a better job and my mind is always learning something new keep up the good work and God Bless You
Just want to say thanks so much Professor for the teachings! Im in the process of wanting to advance in my job and electrical has always been my weekest point. Very well explained and I learned alot! Thanks Again, Kevin
This is excellent - thank you so much for your insight and step by step explanation. This has opened up my understanding as a Mechanical Engineer to PLC's. I sincerely appreciate your time and energy to help us understand. Kind regards, David
I am currently in my 3rd week of plc class at the local community college pursuing a AAS degree in electronic and controls. I have been working in the automotive industry for 5 years as a setter/maintenance, and i have a good understanding of that side of things. After watching your first video and part way into the second, it is just all coming together at a rapid pace. Thank you! I just wonder why the instructor at the college does not take a similar approach, he seems to be all over the place.
I have been blessed with exposure to industrial automation in more ways than most, blessed with the opportunity to work on processes from every sector of industry, many years as a technician, then as an engineer and teacher. The Lord blessed me with a strong desire to teach what I learn and I learn everything in a way that I can explain it. Regardless, most things come with age and experience. Most of what I learned was not in a classroom.
Abdul Rahman Naik There is no other Living God but that of Abraham, Issac and Jacob and there is no other way to a right standing with the living God but through the perfect work of His Son Jesus the Christ. That perfect work of Jesus cannot be earned, it can only be accepted as a free gift of His Grace and Love to all of mankind.
Subhana Allah ...(All glory belongs to Allah) if one can wrap his head around the logic of PLCs, then one has the Logic open himself to Islam... If Allah favors one with guidance. AbduR-Rahman as far as PLCs go you have more of a advantage then most of us, after all Allah did your kin folk to bring us the "0" lol and the walking computer himself ... Dr. Naik may Allah bless him. Ameen !!! Dr. Naik calls us to worship the Creator instead of the created. Just the way Jesus, Muhammad, Abraham, Issac, Jacob and our father Adam (peace on them all) did. here we go, peace
Thank you so much Prof. This is great now I have a clearer view of what a PLC is because currently I am only working on hardware of relays, contactors, solenoid valve and etc.. This will really help me a lot in stepping up to a new level and it's something to do with this feature of Programmable Logic Controller.
Time stamp @1:19:44, Has an error none of the instructions in the rung of logic is true due to input W1 bit 14 pb is pressed because it is a True if off instruction yet the button is depressed. Please clarify because i believe i caught this as an error.
In the bottom diagram in 1:08:20 it's showing a normally open push button connected to I:1:14, which has a normally closed symbol. And then the opposite at 1:29:52. This is different to 55:52. Am I missing something? Does the type of physical switch not relate to the functionality i.e. NO/NC? Also, why does turning I:1:15 on turn O:2.00 on? Is it different to standard circuit series/parallel rules for ladder logic?
@@plcprofessor Thank you for replying so quickly! I think I wasn't clear enough with my question though, sorry, as I'm not talking about changing the symbols. I was thinking "push to make" switches would always be NO in their relaxed state, i.e. _-_ = -| |- and "push to break" are NC i.e. ___ = -|/|-. Is this the case, or does it depend how they're wired up? At 1:08:20, you have _-_ = -|/|- and _-_ = -| |- but at 1:29:52 you have _-_ = -| |- and ___ = -| |- I've figured out my second question I think :)
Lost me at 1:23 I'm old school too much terminology seems like you go to logic control plc writing everything is backwards you're making electrician be an instrumentation person and then you're making them an engineer then you're making a software Hardware developer that's a problem going to a job interview many companies want you to know the ladder programming I'm electrician I give you power you do whatever you want to do with it companies don't seem to understand that greatly don't want to pay you for it but you've taught me a lot so far my memory is mush I think this is what happened when you get three kinds of people trying to engineer design program in install one machine on paper you're very good teacher and thank you I watch your videos Another Day
Jarn Hazir 🤣🤣🤣My computer science friends and I used to call it the "Jaba acshent" because every Java(the programming language) video tutorial I looked up was in an Indian accent, didn't know engineers had the same experience too😆. But Indians are the best, they are very knowledgeable, hardworking and keen on selflesly sharing their knowledge with the world 😊, I feel like you tube needs to have an Indians appreciation day on RUclips 💁♀️💁♀️💁♀️ (My main issue with indian videos wasn't so much the accent as it was the general expressionlessness both in voice tone and in facial expression, not sure if its a cultural thing, but with my attwntion span, the monotony was a huge barrier to learning) As well as a PLC Professor appreciation day, HE'S SIMPLY AMAZING.
No offense but I can't stand to Indian accent and engineering videos are all like that so I try to listen to them for and can't even stay for a minute listening.
I had a recruiter calling me the other day, had to turn down the interview opportunity because I couldn't understand the job description. no offense but damn
At time mark 48:20 when the exploded view of the opto isolator is shown, I think it should be an NPN Transistor with the emitter wired to ground , acting as a sinking device
That would be true for a positive supply, but not for a negative supply like they use outside the US. However, I wish now that I had not used that symbol and made it entirely "polarityless". Most manufactures use sketchy component representations in their wiring illustrations. In the classroom I always mention that these are representations and warranties of information. I added a note that will hopefully allay semiconductor "savvies" from the distraction of what we are actually discussing. Feedback always useful, thank you.
It is the instruction that mimics a relay coil, an instruction that writes to a bit in memory, setting it on of off just like a complete circuit in a relay circuit energizes the coil when the circuit is complete or de-energizes it when the circuit opens.
Yes, you are correct. Unfortunately I normally mention to my classes that this is a representation and not a warranty of actual electronics. In reality there would be a myriad of components between the I/O wiring arm screw terminal and the memory bus. I just thought of a solution, I will make a note to myself to add a note on that section to mention the same. Thanks for the feedback, it all helps. Again, thanks...
plcprofessor Thank you for your reply. At 1:19:35, the question is are there any of the instructions in the rung of logic true. The answer should be none is true because I 1.14, 1.15 and O 2.00 are all false.
+Bruce Wang The three read only instructions are all false, but the write only instruction addressing O:2.00 is never true or false. The TrueIf... instructions are statements about the bits in memory that they address and they are either true or false, these instructions are queries but the "output" instruction is an action that has an action when the rung is true and another action when the rung is false.
I did not get the question asked at 1:19:35 "are any of the instructions in this rung of logic true?" According to me none of the instructions is true, and I did not get the given explanation. Could you please explain in detail. Thanks.
+Mohit Suri I agree with you, instruction 1.14 should be false. That part confused me as well. I just thought it was a mistake in the video. Also, the normally closed pb logic didn't make any sense to me either.
+Mohit Suri There are two read type instructions in that rung of logic, there is a True If On and a True If Off instruction (true if that bit in memory is ON) and there is a True If ON )true if that bit in memory is OFF), just like the contacts of a relay, some have continuity when the relay is ON (True If On) and some have continuity when the relay is OFF (True If Off). There are no mistakes in this explanation, I double checked.
+plcprofessor I see what your point is, but true if On(bit 14) instruction is not displayed on the ladder logic(since word:I:1:1.14 is normally closed contact), so can we say that there would be always one instruction out of the two being true, even though that instruction is not in the ladder logic?
+Mohit Suri The single most difficult point to understand with relay ladder logic is that the symbols that resemble relay contacts are not relay contacts. The "rung" of logic in this graphic is just that, a graphic and not a relay circuit. Those symbols do not open and close, they are either true or false depending upon the state of the bits in memory that they address as a read only instruction.
+Imna Illestchik you have to seperate the physical devices from the logical instructions. a instruction can be false if a bit is off. (an NC instruction is TRUE if the bit is off) for example. And a bit can be ON if for example the button is not being pushed (if its an NC button) so the Physical world just runs from your divices until the input module bit, to determine if this bit is on or off. that bdepends on the type of devices you use NO or NC. from there the logical world starts. The logic looks only to if the input bit is ON or OFF... And the Instructions ADRESSING a certain bit can be TRUE or FALSE wether the bit in on or off depending what instructions you use. then when a output bit is turned on or off the logical world stops again and the physical world starts again. For example i can have a machine turned OFF if an output bit turns ON... and vica versa.... depending on the type of physical contact i use NO or NC
+Imna Illestchik That is not a NO contact, it is a true if ON instruction and it is true because the bit that it is addressing in memory is ON. That bit in memory is ON because the normally closed pushbutton is not pressed and there is continuity in the field circuit turning ON that bit in memory.
What is the class you are taking, if I might ask? After years of both controls engineering and teaching, I still learn something new every time I teach a class. Never stop learning, never stop visualizing your challenges. If you really want to understand something, try explaining it to someone else. You will be amazed at what comes to you when you are searching for the right word picture to illustrate a point.
It is correct, and I go on to explain why people confuse the input device state with the symbols in relay ladder logic. DO NOT THINK relay contacts when you are analyzing RLL. The NO symbol is true if the bit in memory is ON, the NC symbol is true if the bit in memory is OFF, True if On and True if Off are the symbols in RLL, not Normally Open and Normally Closed.
I’m an electrician who joined a company who does a lot of industrial work bringing power to tons of motors, switch gears, smart panels and a lot of controls going back to multiple PLC cabinets. We have one guy who does the programming and another who does controls. We have tons of electricians none of which understand controls. You just brought me into the game. Being the first to understand both worlds in this company. I Might not be a professional in controls but I sure understand it now. Thank you my friend
Just watching these lectures now as I'm studying a degree in mechatronics and they're fantastic! Thank you so much for these
This professor has done a great service to learner's. Although I am a programmer, I could never have given such clear explanation. Thank you Sir, Keep up the good work.
The pleasure is mine...Thank you for the vote of confidence :)
This is great professor explained in detail with plc. Programming THANK YOU FOR explanations.
You can't ask for a better video tutorial. I understood everything you explained. i had to go back a few times, but I eventually got it. The pictures and the way everything was set up was perfect. Great video.
The pleasure is mine...thank you.
PLC Professor, these videos are beyond fantastic. You have truly made a positive contribution to the world. Thank you.
This video is top notch for training and educating. Thank you very much for taking the time to put these together. Thanks for sharing and doing such a great job of narrating and educating our technicians!
Glad it was helpful!
I am about halfway through this video, after having watched part 1. I have basically no PLC background, an amateur electrical background, and lots of programming background.
I actually understand now how an input module isolates field wiring from PLC wiring. It became an epiphany as to how the whole process automation scheme works on a grand scale. When the normally open contact to the light bulb above my head became True, I was going "Wow. Wow!" My wife quirked an eyebrow at me. I said, "Honey, you don't understand. This transcends any religious experience!"
Hyperbole, of course, and some of you more advanced people may sneer, but I am ever grateful to the folks at plcprofessor for having the heart to produce this video and the balls to make it freely available.
all lies electricity - plc is a system in switching mode by the transmission of light...
Masterful teaching. Thank you for explaining the Fundamentals first.
Taking PLC fundamentals at college, his video has thought me more than what I've learned in the entire semester !! Way to go professor, now I need to learn how to program
I've never had a thorough lecture like this....really downtown basics! Thanks so much prof!
At my 57 years I went again to school to get my electrician carta proffesional II, I have a solar energy company and with your help I will pass the test next week. It is so nice explained, thank you Sir. Greetings from portugal
The pleasure is mine...el gusto es mio.
Excellent. This refresher has been exactly what I needed in a short but detailed package. You may count yourself amongst the "good guys" for doing this!
ok professor, i watched this video, and its starting to make sense now about the true if on, false if off, or true if off, false if on, your great, not knocking my instructor, but i can really understand you alot better than i can him, man your a godsend to me, and i may just have a chance at passing this class
Thank you for the excellent teaching. This was very clear thanks to your 'foundations first' approach. The progression from relay basics to the more advanced PLC hardware really made this very understandable. You are a gifted teacher.
Thank you very much.. This is by far the best lesson on PLCs that I have found on Internet. Highly recommended!
thank you...
God bless you for making this public and free of charge.
Best tutorials I ever watched on any topic on youtube. Thanks for the time and efforts.
God Bless you.
Thank you so much.. I am beginning a job in controls and have absolutely no experience. These videos have enabled me to learn the PLC fundamentals without going to school and better yet for free! Your dedication to online learning is much appreciated :) !!! Thank you
Professor thanks very much for your efforts the detail and effort you go into for people with no experience is as good as it gets. Very grateful :)
plcprof, Again, this is a great video. I am reviewing these, but learning a lot in the process. I like what you have done and have encouraged others in my group to watch these also. Keep it going.
you said thank you for watching but we say thank you for teaching to understand basic information
Sir, It's strange without introducing yourself in photo or picture you explain the PLC course in simple way, It's great.Thnx
Thank you very much i really enjoyed the ride and i dont recall the last time i learned that much from a youtube lecture.
You're very welcome!
amazing tutorial . I watched both the parts in one go. Simple and clear.
Awesome, thank you!
Thank you for taking the time. I am beginning to understand. Your patience and persistence is making a difference.
Thanks for spend your time teaching other ones these two videos are really good, I´ve learned a lot.
Plc Professor, you are the best. You make an interesting subject even more interesting. Thanks
The pleasure is mine...
Really helps those of us with a pre-existing knowledge of electricity and schematics. A great started video. I'd like to see more of his explanation videos of more in depth programming.
This is great. I had a couple teachers like this in school. Very good, knew how to explain things to make people understand.
I just wanted to say that I greatly appreciate all the work you have put into this 2 part introduction.
Thanks for the two parts. I think those are some of the best youtube lectures I have ever seen on any topic.
Thank you, what your doing is truly helpful to mankind. The abundance of knowledge is changing my life.
This is a great video. I'm learning more about PLC, and I am continue learning from your videos. Thank you very much for your hard work!
Great to hear!
thanks so much for putting the time and effort into something so powerful and beneficial such as plc progamming.I'm in the process of taking my PLC classes and th
ese videos really helped me a lot. thanks professor and keep up the good work.
you ROCKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK.
i vaiue all the information that your teaching me. Ive shared you site with my friends and hope they support you. With what your teaching me im sure i get a better job and my mind is always learning something new keep up the good work and God Bless You
Great work. Excellent video for the PLC learners. Thanks a lot.
You are the best out there sir!! Studies are so much fun if taught in this manner!!
Thanks for the upload! :)
Very good explanation and demonstration.!! It is much more clear to me how the PLC logic works. Thank you
Just want to say thanks so much Professor for the teachings! Im in the process of wanting to advance in my job and electrical has always been my weekest point. Very well explained and I learned alot! Thanks Again, Kevin
Another great PLC video...keep up the great teaching
Amazing video. Excellent teaching. Great visuals. Thanks for your time and efforts.
This is excellent - thank you so much for your insight and step by step explanation. This has opened up my understanding as a Mechanical Engineer to PLC's. I sincerely appreciate your time and energy to help us understand. Kind regards, David
I am currently in my 3rd week of plc class at the local community college pursuing a AAS degree in electronic and controls. I have been working in the automotive industry for 5 years as a setter/maintenance, and i have a good understanding of that side of things. After watching your first video and part way into the second, it is just all coming together at a rapid pace. Thank you! I just wonder why the instructor at the college does not take a similar approach, he seems to be all over the place.
I will be finishing this series as a suppliment to my schooling.
I have been blessed with exposure to industrial automation in more ways than most, blessed with the opportunity to work on processes from every sector of industry, many years as a technician, then as an engineer and teacher. The Lord blessed me with a strong desire to teach what I learn and I learn everything in a way that I can explain it. Regardless, most things come with age and experience. Most of what I learned was not in a classroom.
plcprofessor Peace be upon you.
Who is Lord according to you, sir ???
Abdul Rahman Naik There is no other Living God but that of Abraham, Issac and Jacob and there is no other way to a right standing with the living God but through the perfect work of His Son Jesus the Christ. That perfect work of Jesus cannot be earned, it can only be accepted as a free gift of His Grace and Love to all of mankind.
Subhana Allah ...(All glory belongs to Allah) if one can wrap his head around the logic of PLCs, then one has the Logic open himself to Islam... If Allah favors one with guidance. AbduR-Rahman as far as PLCs go you have more of a advantage then most of us, after all Allah did your kin folk to bring us the "0" lol and the walking computer himself ... Dr. Naik may Allah bless him. Ameen !!! Dr. Naik calls us to worship the Creator instead of the created. Just the way Jesus, Muhammad, Abraham, Issac, Jacob and our father Adam (peace on them all) did. here we go, peace
Thank you, I am reentering the job market and this was great refresher. Good job.
I am very much grateful professor. you are more than a professor.
The pleasure is mine.
Thank you so much Sir, for sharing this video with us. This is a big help for me as an industrial electrician.
PlcProfessor thank you very much for the free knowledge!!!
You are awesome!!!
thank you "plc professor" for the tutorial simple and effective.
Thank you for detailed, simplified excellent lecture
Unique and highly appreciated,
thank you.
You are most welcome, it was my pleasure.
The most complete and detailed material that I´ve seen available to learners. Congratulations and thank you soo much professor.
Excellent video, thank you very much for your time dedicated to the development of video, Greetings from Mexico!!!
el gusto es mio...
Thank you sir. This was very confusing for me but you explained it in a very smooth way!! Thanks again.
Dear professor, thank you for giving us such a good training.
It's my pleasure
Thank you for taking time to straighten out the tricky stuff right around1:00:00. Very helpful!
This is absolutely excellent. Keep it up professor
Thank u so much I feel so confident now to approach PLCs without that fear ;)
Your explanation is great and easy to understand. Thank you sir.
This was an awesome presentation. Parts 1 & 2. Thank You!!!
Thanks for sharing very good presentation it's helpful
Thank you so much Prof. This is great now I have a clearer view of what a PLC is because currently I am only working on hardware of relays, contactors, solenoid valve and etc.. This will really help me a lot in stepping up to a new level and it's something to do with this feature of Programmable Logic Controller.
came from military and just doing relays this has been helpful as a transition to civilian world with plcs
thank you...
great video thanks so much, am learning so much continue to take your time for us, slow learners
I appreciate, sir. always feel comfortable with your lectures. thank you very much❤
Thanks you so much sir, for your video it so clear and educative keep it up, yearning to know more from you as programmer beginner.
Very good, sir. You are an excellent instructor, thank you.
The pleasure is mine...
Your lectures are fantastic
When you open the Micro Starter Lite, under the help tab select Instruction help. It has detailed explanations of each instruction.
ABSOLUTELY THE BEST!! You have a teaching gift, sir.. THANK'S!!
Pretty specific and with nice examples! I like it!
Time stamp @1:19:44, Has an error none of the instructions in the rung of logic is true due to input W1 bit 14 pb is pressed because it is a True if off instruction yet the button is depressed. Please clarify because i believe i caught this as an error.
AMMMAZING👐👐👐👐 Thank you so much, you're a beyond amazing video instructor. Thank you for the videos. Very very much appreciated.
thanks for an awesome explanation great job, greetings from a mexican !!!!
In the bottom diagram in 1:08:20 it's showing a normally open push button connected to I:1:14, which has a normally closed symbol. And then the opposite at 1:29:52. This is different to 55:52. Am I missing something? Does the type of physical switch not relate to the functionality i.e. NO/NC?
Also, why does turning I:1:15 on turn O:2.00 on? Is it different to standard circuit series/parallel rules for ladder logic?
All contacts are drawn in their "normal" or relaxed state. You do not change the symbol to match it's energized state.
@@plcprofessor Thank you for replying so quickly! I think I wasn't clear enough with my question though, sorry, as I'm not talking about changing the symbols.
I was thinking "push to make" switches would always be NO in their relaxed state, i.e. _-_ = -| |- and "push to break" are NC i.e. ___ = -|/|-. Is this the case, or does it depend how they're wired up?
At 1:08:20, you have _-_ = -|/|- and _-_ = -| |- but at 1:29:52 you have _-_ = -| |- and ___ = -| |-
I've figured out my second question I think :)
Thank you for such a clear and concise explanation!!!
Thanks for the beautiful explanation. Great job..
Lost me at 1:23 I'm old school too much terminology seems like you go to logic control plc writing everything is backwards you're making electrician be an instrumentation person and then you're making them an engineer then you're making a software Hardware developer that's a problem going to a job interview many companies want you to know the ladder programming I'm electrician I give you power you do whatever you want to do with it companies don't seem to understand that greatly don't want to pay you for it but you've taught me a lot so far my memory is mush I think this is what happened when you get three kinds of people trying to engineer design program in install one machine on paper you're very good teacher and thank you I watch your videos Another Day
Thank you so much for the videos. I watch tubalcain videos for my machine shop training and yours for my PLCs.
at 22.00 the hexadecimal number A0F1 should be 41201 in decimal. Great job on the videos.
This is the first video I've seen on engineering by someone that doesn't have an Indian accent
Jarn Hazir 🤣🤣🤣My computer science friends and I used to call it the "Jaba acshent" because every Java(the programming language) video tutorial I looked up was in an Indian accent, didn't know engineers had the same experience too😆. But Indians are the best, they are very knowledgeable, hardworking and keen on selflesly sharing their knowledge with the world 😊, I feel like you tube needs to have an Indians appreciation day on RUclips 💁♀️💁♀️💁♀️ (My main issue with indian videos wasn't so much the accent as it was the general expressionlessness both in voice tone and in facial expression, not sure if its a cultural thing, but with my attwntion span, the monotony was a huge barrier to learning) As well as a PLC Professor appreciation day, HE'S SIMPLY AMAZING.
No offense but I can't stand to Indian accent and engineering videos are all like that so I try to listen to them for and can't even stay for a minute listening.
🤣🤣🤣
I had a recruiter calling me the other day, had to turn down the interview opportunity because I couldn't understand the job description. no offense but damn
nice work! keep on your good work. very fascinating!
Thank you! This classes really help me out.
I just can say . god bless you.
At time mark 48:20 when the exploded view of the opto isolator is shown, I think it should be an NPN Transistor with the emitter wired to ground , acting as a sinking device
That would be true for a positive supply, but not for a negative supply like they use outside the US. However, I wish now that I had not used that symbol and made it entirely "polarityless". Most manufactures use sketchy component representations in their wiring illustrations. In the classroom I always mention that these are representations and warranties of information. I added a note that will hopefully allay semiconductor "savvies" from the distraction of what we are actually discussing. Feedback always useful, thank you.
Thank you for your very clear explanation
Teach by repetition. Great teacher, only way I could grasp some of these concepts.
1:16:25 - You begin here talking about OTE; will you explain what that is, or did I miss something in the previous lesson?
It is the instruction that mimics a relay coil, an instruction that writes to a bit in memory, setting it on of off just like a complete circuit in a relay circuit energizes the coil when the circuit is complete or de-energizes it when the circuit opens.
Yes, you are correct. Unfortunately I normally mention to my classes that this is a representation and not a warranty of actual electronics. In reality there would be a myriad of components between the I/O wiring arm screw terminal and the memory bus. I just thought of a solution, I will make a note to myself to add a note on that section to mention the same. Thanks for the feedback, it all helps. Again, thanks...
Ok, let me ask this, at 1:19:35, if bit 14 is on, instruction 1.14 becomes false. Is this correct?
+Bruce Wang YES... If bit 14 is ON then any "TrueIfOFF" instruction that addresses it is false... because it is not OFF and therefore false.
plcprofessor Thank you for your reply. At 1:19:35, the question is are there any of the instructions in the rung of logic true. The answer should be none is true because I 1.14, 1.15 and O 2.00 are all false.
+Bruce Wang The three read only instructions are all false, but the write only instruction addressing O:2.00 is never true or false. The TrueIf... instructions are statements about the bits in memory that they address and they are either true or false, these instructions are queries but the "output" instruction is an action that has an action when the rung is true and another action when the rung is false.
PART 1 was fantastic,let me try part2...Hope I understand this too..
I did not get the question asked at 1:19:35 "are any of the instructions in this rung of logic true?" According to me none of the instructions is true, and I did not get the given explanation. Could you please explain in detail. Thanks.
+Mohit Suri I agree with you, instruction 1.14 should be false. That part confused me as well. I just thought it was a mistake in the video. Also, the normally closed pb logic didn't make any sense to me either.
+Mohit Suri There are two read type instructions in that rung of logic, there is a True If On and a True If Off instruction (true if that bit in memory is ON) and there is a True If ON )true if that bit in memory is OFF), just like the contacts of a relay, some have continuity when the relay is ON (True If On) and some have continuity when the relay is OFF (True If Off). There are no mistakes in this explanation, I double checked.
+plcprofessor at 1:19:35, if bit 14 is on, wouldn't it open 1.14 thus instruction 1.14 becomes false?
+plcprofessor I see what your point is, but true if On(bit 14) instruction is not displayed on the ladder logic(since word:I:1:1.14 is normally closed contact), so can we say that there would be always one instruction out of the two being true, even though that instruction is not in the ladder logic?
+Mohit Suri The single most difficult point to understand with relay ladder logic is that the symbols that resemble relay contacts are not relay contacts. The "rung" of logic in this graphic is just that, a graphic and not a relay circuit. Those symbols do not open and close, they are either true or false depending upon the state of the bits in memory that they address as a read only instruction.
Great Lecture, thank you Sir! One thing that was never explained (or maybe I didnt hear) is what does OTE means.
Thank you, thank you so much for these clear explanations.
Thank you professor it is a grate explanation, I going to kip washing until learning and programming.
I'm one of those people. I'm really lost at 59:07. Could someone explain that, please. The NO is true because the circuit is on?
+Imna Illestchik you have to seperate the physical devices from the logical instructions. a instruction can be false if a bit is off. (an NC instruction is TRUE if the bit is off) for example. And a bit can be ON if for example the button is not being pushed (if its an NC button) so the Physical world just runs from your divices until the input module bit, to determine if this bit is on or off. that bdepends on the type of devices you use NO or NC. from there the logical world starts. The logic looks only to if the input bit is ON or OFF... And the Instructions ADRESSING a certain bit can be TRUE or FALSE wether the bit in on or off depending what instructions you use. then when a output bit is turned on or off the logical world stops again and the physical world starts again. For example i can have a machine turned OFF if an output bit turns ON... and vica versa.... depending on the type of physical contact i use NO or NC
+Imna Illestchik That is not a NO contact, it is a true if ON instruction and it is true because the bit that it is addressing in memory is ON. That bit in memory is ON because the normally closed pushbutton is not pressed and there is continuity in the field circuit turning ON that bit in memory.
What is the class you are taking, if I might ask? After years of both controls engineering and teaching, I still learn something new every time I teach a class. Never stop learning, never stop visualizing your challenges. If you really want to understand something, try explaining it to someone else. You will be amazed at what comes to you when you are searching for the right word picture to illustrate a point.
Very well presented, Thank You.
Awesome video professor!😁
Glad you liked it!
Now that's what i call a professor !!!
Thank you.
It is correct, and I go on to explain why people confuse the input device state with the symbols in relay ladder logic. DO NOT THINK relay contacts when you are analyzing RLL. The NO symbol is true if the bit in memory is ON, the NC symbol is true if the bit in memory is OFF, True if On and True if Off are the symbols in RLL, not Normally Open and Normally Closed.
Thank you for this information this was very helpful to me.
You are so welcome!
Thank you so much you make it really easy to understand