Great presentation. I'm learning Ladder Logic working in Automation with a very senior programmer who this stuff is a piece of cake for. I'm in the deep end of the pool leaning this stuff so everything helps. That Normally Close Contact j(Non-Exempt) just twist the hell out of my brains understanding things. Anyway great presentation and very understandable with what i know so far.
Awesome video! I watched to see if this will be a good video to have my entry level techs view for learning L-logic.. It is one of, if not the clearest, stay on point, easy to understand and well explained logic videos on RU-vid in my opinion. So thank you for taking the time to make it. I noticed the start button shown from 1:47 on is actually a stop button placed by mistake, I'm guessing. Great video regardless.
I appreciate the comment! We have much more content on our PLCMentor website and it was designed around maintenance techs that need to learn but where it's hard to do without them for a week.
Actually I m having experience in electrical field so I don't know about PLC but I am having so much interest to learn about PLC.only one thing I know about PLC that is DI,DO,AI and AO...whatever u said in this I understood easily...
In the beginning of this video the stop button is shown as NC, push to open, the logic later in the video shows the logic using a XIO for the stop PB function. The stop PB should be XIC if the logic is to mimic a standard three wire start/stop PB station. The stop PB's should always be wired NC, push to open so that if a wire is broken in the circuit, the output in the logic will shutdown if running or be unable to be started if not running. If unable to start or shutdown occurs, the circuit can be troubleshot at that point and repaired. This is the failsafe method to wire this type of circuit as some "stop" PB's are in place to be used in critical shutdown situations. I was wanting to use this video in my class at the community college because the graphics and explanations are clear, but I can't because of the error mentioned in my comment.
Yes stop bits, like their hardwired counterparts should always be N.C., or "XIC" in ladder logic software for "fail safe" operation. But when I would explain Ladder logic programming to people with little or no electrical background i would usually try to dispense with most of the Normally closed, examine if closed, on, off, Hi, Low, ones and zeros, etc. All of that language, while useful can be very confusing to those without the background in electrical switching, relays etc, and they tend to, in my experience, get hung up on these concepts when much of it is unnecessary to learning to read the logic. I would instead present it like this: I would tell them to divide the screen into left and right. On the left side you have a set of "conditions" and on the far right you have an "outcome" based on those conditions. If the conditions are "true" then the outcome will then be true and of course if they are false the outcome will also be false. I would tell them to forget about all of the N.C., N.O. stuff for the moment and pay attention instead to the green highlights. If it is green then its true regardless of anything else. It is of course an oversimplification but I found it to be effective in getting people, with little and sometimes no experience, reading and understanding ladder logic without getting hung up on the whole Normally closed, on, off, concepts.
Yes stop bits, like their hardwired counterparts should always be N.C., or "XIC" in ladder logic software for "fail safe" operation. But when I would explain Ladder logic programming to people with little or no electrical background i would usually try to dispense with most of the Normally closed, examine if closed, on, off, Hi, Low, ones and zeros, etc. All of that language, while useful can be very confusing to those without the background in electrical switching, relays etc, and they tend to, in my experience, get hung up on these concepts when much of it is unnecessary to learning to read the logic. I would instead present it like this: I would tell them to divide the screen into left and right. On the left side you have a set of "conditions" and on the far right you have an "outcome" based on those conditions. If the conditions are "true" then the outcome will then be true and of course if they are false the outcome will also be false. I would tell them to forget about all of the N.C., N.O. stuff for the moment and pay attention instead to the green highlights. If it is green then its true regardless of anything else. It is of course an oversimplification but I found it to be effective in getting people, with little and sometimes no experience, reading and understanding ladder logic without getting hung up on the whole Normally closed, on, off, concepts.
Yes stop bits, like their hardwired counterparts should always be N.C., or "XIC" in ladder logic software for "fail safe" operation. But when I would explain Ladder logic programming to people with little or no electrical background i would usually try to dispense with most of the Normally closed, examine if closed, on, off, Hi, Low, ones and zeros, etc. All of that language, while useful can be very confusing to those without the background in electrical switching, relays etc, and they tend to, in my experience, get hung up on these concepts when much of it is unnecessary to learning to read the logic. I would instead present it like this: I would tell them to divide the screen into left and right. On the left side you have a set of "conditions" and on the far right you have an "outcome" based on those conditions. If the conditions are "true" then the outcome will then be true and of course if they are false the outcome will also be false. I would tell them to forget about all of the N.C., N.O. stuff for the moment and pay attention instead to the green highlights. If it is green then its true regardless of anything else. It is of course an oversimplification but I found it to be effective in getting people, with little and sometimes no experience, reading and understanding ladder logic without getting hung up on the whole Normally closed, on, off, concepts.
Yes stop bits, like their hardwired counterparts should always be N.C., or "XIC" in ladder logic software for "fail safe" operation. But when I would explain Ladder logic programming to people with little or no electrical background i would usually try to dispense with most of the Normally closed, examine if closed, on, off, Hi, Low, ones and zeros, etc. All of that language, while useful can be very confusing to those without the background in electrical switching, relays etc, and they tend to, in my experience, get hung up on these concepts when much of it is unnecessary to learning to read the logic. I would instead present it like this: I would tell them to divide the screen into left and right. On the left side you have a set of "conditions" and on the far right you have an "outcome" based on those conditions. If the conditions are "true" then the outcome will then be true and of course if they are false the outcome will also be false. I would tell them to forget about all of the N.C., N.O. stuff for the moment and pay attention instead to the green highlights. If it is green then its true regardless of anything else. It is of course an oversimplification but I found it to be effective in getting people, with little and sometimes no experience, reading and understanding ladder logic without getting hung up on the whole Normally closed, on, off, concepts.
Yes stop bits, like their hardwired counterparts should always be N.C., or "XIC" in ladder logic software for "fail safe" operation. But when I would explain Ladder logic programming to people with little or no electrical background i would usually try to dispense with most of the Normally closed, examine if closed, on, off, Hi, Low, ones and zeros, etc. All of that language, while useful can be very confusing to those without the background in electrical switching, relays etc, and they tend to, in my experience, get hung up on these concepts when much of it is unnecessary to learning to read the logic. I would instead present it like this: I would tell them to divide the screen into left and right. On the left side you have a set of "conditions" and on the far right you have an "outcome" based on those conditions. If the conditions are "true" then the outcome will then be true and of course if they are false the outcome will also be false. I would tell them to forget about all of the N.C., N.O. stuff for the moment and pay attention instead to the green highlights. If it is green then its true regardless of anything else. It is of course an oversimplification but I found it to be effective in getting people, with little and sometimes no experience, reading and understanding ladder logic without getting hung up on the whole Normally closed, on, off, concepts.
My question is how you can use XIO instruction to address the NC stop button, stop button is normally close and always conducting in normal position and should be addressed with a XIC instruction to be true.
Great tutorial, but the I/O wiring diagram at 1:51 shows a normally closed start button which you would never do, as a broken wire would initiate a start command. Also, the program shown later is using an "on" signal to activate the start condition in the logic, which would be fed from a N/O contact. The stop button would be wired normally closed as shown at 1:51 but the PLC input would be looking for an "on" signal to keep the coil output energized, not an "off" signal like the logic shows. I see how you are trying to relate the code to a hardwired circuit, but this might confuse someone if they are trying to compare the logic, the hardwired circuit, and I/O connection diagram.
graziemerci Yes that is true! Never noticed that before and I dont think anyone has ever brought that up here. I will point out that the discussion is on how real world devices get into the PLC and that discussion is still valid.
Master... feel funny replying like that - check out our PLCMentor site and we have information on that in the announcements on our front page. It is actually the real RSLogix500 software that you would use to program on the job and the RSEmulate that we use periodically to test our programs. In short, its the real software so learning to use it is actually useful. Our link is to the Rockwell site where they give out a micro lite version that is legal and approved.
+automationnc m using a CTD count down counter in my plc program. how do i stop it from going past 0? it ends up going -1.-2 etc?? its a parking lot application s. thanks for your help
+Master Mo You can address the accumulator (.ACC) and add a GRT statement to check and see if the accumulator is greater than 0. So (C5:0.ACC > 0) ahead of your counter would only allow it to count down if the accumulator is greater than 0. Keep in mind if there are more cars leaving the parking lot than came in then you should have some sort of alarm. So the attendant knows there is something wrong.
develop a ladder logic diagram for a car door/seat belt safety system.when the car door is open or seat belt is not done up,the ignition power must not be applied.if all is safe then key can start the car?
If you are asking about real world inputs/outputs versus internal inputs and outputs then that dependent on the address used. Certain addresses are tied to real world inputs, some real world outputs and others internal elements.
Thanks for the tutorial. I'm a beginner in PLCs and a local JC instructor has allowed me to sit in on classes although I'm not an enrolled student (no $$ for tuition or books) but I'm trying to get a grasp on things. The class is on to using masks on program. Do you have any tutorial of pdfs that I can use to learn masks with sequencers? Thanks again.
Best plan there is to be honest with your employer or interviewer. Show your willingness to improve and learn like you are doing here and it will go a long way towards your success.
I need some information on RS Logix programming for AB Micrologix 1200. If suppose, we have a sensors in field connected to the Digital Input of the controller. This sensor is connected to a conveyor, this gets signal ON and OFF contentiously every second or less than a second. I need to activate an output relay port only if the input is constantly ON for more than 5 seconds. Please advise how this can be done.
Could you please share examples of the different ways that different processors work on the logic when the logic is scanned? Does Allen Bradley Compact Logix modules have different data handling schemes compared to Allen Bradley's MicroLogix modules or compared to Siemens S7 plc card modules?
At 17:21 you said "If you look at this frame you will see that the start pushbutton is pressed." How do you know it is pressed by looking at the frame?
Mark Griggs You can tell it is pressed by its highlighted state. And yes it is a valid point that you cannot always rely on the highlighted state while online, I feel that topic would get into a more advanced discussion than necessary in an introduction.
Please how can I make M1 0.2 coil works with M1 O.2 contact. I am having an issue making both goes a the same time. ( When M1 coil gets energy it would automatically close M1 contact Which is actually an NO contact. Please how to make both communicate.
Hello sir I have Allen Bradley plc5 .. when communicating with plc for trouble shooting online cross reference is not enabled so let me know the solution on this ..?
@@ravindradesai5007 First you cannot selectively download in the PLC5. All or nothing. To change the preset on a timer in the PLC5, you just need to go to the instruction and change it right there. You could also change it in the data table.
when the plc make the scan cycle he will find that the stop button is closed he will go to the programe and apply 1 to the stop button input it wil be no "the scan cycle confused me"
great tutorial i'm beginner to learn plc i need so much tutorial to make project with plc any one of you can give some website or link to can visit learn plc for beginner...
I am not familiar with that IDEC PLC but it looks like it has an RS232 serial port. Judging from the round connector, you will probably have to get the cable from your IDEC rep. You also may need a USB to RS232 adapter for your PC as most PC's now days dont have comm ports. You can just google the model and microsmart and come up with lots of information on it. The manuals are located here: us.idec.com/Catalog/ProductDetails.aspx?ProductId=FC4A-C24R2&FamilyName=Family&SeriesName=MicroSmart
You weren't kidding about it being an introductory to PLCs. if you are brand new to PLCs this would be very helpful, but if you are like me and need a refresher course in PLCs then you should look else where. Anyways good job on the presentation.
Allen Warner Very introductory - yes. The information on our site goes into much greater detail. I believe we are the only site that will review student's programs as well as a live web class. Not to mention our material was put together by Engineers that are actively designing, programming and commissioning control systems.
is the purchased video include any simulation of PLC for further practice?? I mean what if i want to create some other ladder circuit, i want to know it work or not, do you provide the simulator software??/
+fatmachinist fataman No we do not, but we use some freebie software provided by Rockwell. It is not some silly simulator, but the actual software that you would use to program in industry. They also offer their emulator for free to test the software. We have more information on our site.
It is another standard graphical PLC programming language. The code is constructed using blocks/function blocks, which are connected to each other properly.
Good question! The only answer being a matter of definition. If we were drawing an electronic circuit for a circuit board then you would expect the parallel lines to be a cap. When you move to the industrial drawings and standards there, particularly relay logic diagrams, the parallel lines are accepted as contacts.
+automationnc how very interesting. I'm actually in the railways where relay logic is used to design interlocking systems. we still use contacts similar to the conventions seen in a circuit board. I'm pretty sure my circuit books are defined "industrial". anyway, more than one way to skin a cay, I suppose. i guess it's easier to draw it that way than the actual contacts and if there's no conflict with capacitors, then it will be okay.
PLEASE anyone save me. I've made PLC test with a Micrologix 1500 and I could not use the standart addreess like B3:0/0. Instead, I was able to insert a memory bit like B3/0. WHY? Why all address was changed in Rslogix?
You really should be able to use either. How they show up in your program is defined by how you setup your RSLogix500 options. Both mean the same thing, and only bit data files have this flexibility in addressing. Your first example is a method that includes the word and bit in the address (B3:0/0 - first 0 is word - second is bit). The second example is addressing without the word (B3/0 - where the 0 is the initial bit in that data file). With the B3/0 type of addressing you can address without using the word and get addresses like B3/16 (same as B3:1/0) or B3/200. It can be a little confusing as you have to understand words and bits and such to really understand how it works. Check out our video on numbering systems to help with that.
Numbering Address I know how to do it, What I didn't know is how to set up this feature in Rslogix 500. After 15 years, today I spent all this morning and Thanks God I could find how to set up this options in RS logix 500. VIEW-->PROPERTIES-->ADDRESS DISPLAY TAB-->BINARY BIT DISPLAY MODE-->BIT. Even so, thanks so much for your help.
I really wanted to watch this, as it seems like a good presentation, but the constantly moving about pencil icon was just too annoying. A couple minutes of that was it for me!
But.. it doesnt really matter with a plc. It's electronic. There is no loose wire to come off if it comes from an HMI. Of course if you want to have hardwired inputs into the PLC you can make the point for a NC stop PB. Thanks for the comment!
@automationnc safety, safety, safety. If you use a normally open stop to an XIO instruction and the wire breaks or contact doesn't seal you'll never get it to turn off minus e-stop circuit. Showing this leads people to a mojor error
Cody Harfield Interesting. What exactly is wrong? Ron and I have some different ways of presenting the material. I have found my methods work well for most. I am sure Ron has good results too and I also recommend his videos. In fact we also show his videos on our site as they are good information.