As stated this was very confusing for me as well when I started to learn PLC's. I had an 'aha' moment when a mentor explained it to me differently. He called the PLC instruction NO a 'copy cat' instruction and the NC instruction a 'Contrary' instruction. The copy cat (NO) will just follow the state of the physical switch. The contrary does the opposite of the physical switch. Life has been so much better once I got over that mental hurdle. I have never seen this terminology used anywhere else, but I use when teaching my students and it generally goes over pretty well. Thanks for the video.
@alvieteal4980
11 ай бұрын
I do like how simple you make it saying “the no looks for a 1 and the nc looks for a 0”
@rodolforodriguez70
2 жыл бұрын
Excellent explanation , the problem here in CR is that there are old schools electricians that used real relays in control
@koosvanrensburg95
4 жыл бұрын
Tim, thank you I am familiar with electronics and am a programmer for many years, mostly business systems, RPG, COBOL, Pascal, VB ets but I am new to PLC and ladder I have spoken to half a dozen people and watched tenths of videos, and just when I think I got it I read something and then I am not sure anymore Until you said “No matter you use NO or NC actual contact, the line of code refers to either a 1 or 0 in the registry associated with that X?, “ understood if the LED on plc is ON the NO test will be true and the NC test will be false, regardless what type of switch you use on that plc that finally clarified the matter, testing for a condition/definition in the plc. That is That Thanks again, keep up the good work
@TimWilborne
4 жыл бұрын
Glad we could help you understand. If you have any questions then feel free to ask!
@alvieteal4980
11 ай бұрын
I guess if you are associating it with the contact it’s connected to then it becomes confusing
@alvieteal4980
11 ай бұрын
I don’t understand how it’s so difficult. I like associating them with no and nc it actually makes it easier for me.
@TimWilborne
11 ай бұрын
I'm glad it works for you.
@jackpast
5 жыл бұрын
Can’t see how you can learn plc programming without relay and push button logic knowledge. If you don’t know that all ‘Stop’ pushbuttons need to be wired using a N/C contact in the motor control circuit, and ‘Start’ pushbutton contacts are wired to the N/O contact, you wouldn’t know that in your plc motor control circuit you would use a N/O plc contact for the ‘Start’ N/O push button input and a N/O plc contact for the ‘Stop’ N/C push button. It seems a lot easier to understand than to put it in writing and evidently in a video. You use the N/C contact on your ‘Stop’ button to have a broken wire or loss of control power prevent the starting of a motor. Great topic! I say to everyone in industry...learn 3 wire control first THEN plc basic programming.
@TimWilborne
5 жыл бұрын
Great comments. I think a lot of the differences in opinion line up along whether you learned electrical before you learned PLC programming. I won't argue that it would be better to learn electrical before learning PLC programming, it just doesn't always happen that way. Looking back, I probably was a decent PLC programmer 2 or 3 years before I had a basic electrical foundation. Thanks for watching!
@colincampbell5207
Жыл бұрын
I just went from a facility that uses AB to a facility that uses Proficy. AB makes way more sense to me because in my mind PLC programming is akin to asking a question. Examine (address) if closed (?) Yes or no? Examine (address) if Open (?) Yes or no?
@lmc00rage
5 жыл бұрын
I too did not understand the confusion, but now I see how Normally Closed and Normally Open can be misunderstood. Examine if Open and Examine if Closed are better terms for describing the instruction, but I think some people understand (or misunderstand) better/quicker using NC or NO as their terms. Liked the description that "this symbol goes and looks for a 1, then it will always work". The -| |- instruction by any other name would still do the same function hahaha
@TimWilborne
5 жыл бұрын
It has been a great conversation starter. Thanks for watching! Now I need to figure out next weeks video. I'm still working on the new analog series.
@familjen5863
3 жыл бұрын
This is so clarifying, thanks
@TimWilborne
3 жыл бұрын
You are welcome!
@warlax5658
4 жыл бұрын
i don't understand why thet dont just call it, like, an IF TRUE or a IF FALSE or something. it seems like the propensity to simplify things by relating them to other things makes it confusing for no reason
@TimWilborne
4 жыл бұрын
Hi Daniel. IF TRUE and IF FALSE has some pitfalls too. Let's say you have an XIO Examine if Open or as I call it "Go look for a 0". If you say "IF FALSE and the bit has a zero in it then you are saying since this instruction "IS FALSE" then pass true conditions to the next instruction. Go look for a 1 and Go look for a 0 are the best terms I've found.
@techtopics5782
2 жыл бұрын
It's confusing because most people giving instruction on PLCs, from my experience, are guys who have worked in the electrical field. Most trade colleges that teach this have retired industrial electricians teaching that NC and NO contacts in switches are the same as logic in programming. It's not the same thing and should never be explained or taught that it is the same. A programmer should teach programming from a programming perspective. Not electricians who have sound knowledge of electrical circuits but a fuzzy knowledge of programming. Most electricians lack a programming background so I don't know why trade colleges expect them teach it. Anyway, Tim I like your videos. You and your wife are a hilarious team.
@TimWilborne
2 жыл бұрын
Thanks!
@alearnerforsafety3692
4 жыл бұрын
EIC look for 1 ( in the Input Data box bits) to be True and EIO look for 0 ( in the input Data box bits) to be True, but who will determines whether it will write 0 or 1 in this input data box bits ? Is it current flow or voltage etc... , please explain this points , thanks.
@TimWilborne
4 жыл бұрын
See if this lesson helps www.theautomationstore.com/rslogix-500-training-basic-on-off-control-xic-xio-ote/
@alearnerforsafety3692
4 жыл бұрын
@@TimWilborne Thanks
@AleksaPirot
4 жыл бұрын
I don`t get it. For example, let`s take a look at the NO electrical contact. If the "1" is found (acivated), the instruction is true, and you have 24V at the output. Isn`t this the same what XIC does? Same thing with the NC (XIO)- if you have a "0" (not activated), instruction is true and you have 24V at the output. Am I missing something here?
@TimWilborne
4 жыл бұрын
How do you define "activated"? Simply connected a normally closed stop button to the above breaks the definitiion.
@AleksaPirot
4 жыл бұрын
@@TimWilborne well, if those are the relay contacts we're talking about, than whenever there's voltage on relay coil, it's contacts are activated. Judging by this logic, if we have voltage on relay solenoid (logical 1), their NO contacts do have 24V on the output, while NC contacts don't. Just the same what XIC and XIO do. To be quite honest I really don't see the difference here.
@TimWilborne
4 жыл бұрын
@@AleksaPirot "well, if those are the relay contacts we're talking about". You are all over it. What if they are not?
@AleksaPirot
4 жыл бұрын
@@TimWilborne same thing. NO push button seeks for a 1 (pushed), and if it founds 1, than the output is 1. NC push button seeks for a 0 (not pushed), and if it is not pushed, than the logic is true and we have the output.
@TimWilborne
4 жыл бұрын
@@AleksaPirot Yes but you are still lining up your terms perfectly. Connect a normally open push button (button 1) to a XIO or a normally closed push button (buttton2) to an XIC then think about it looking at the program and the push button. You said earlier a "1" is "activated". So the beginner programmer opens up the program and sees that he sees that the button 1 has an XIO instruction and thinks...that means it is normally closed. He looks over at button 1 and it is not pressed so it is not "activated" but the program is saying that it is. Similarly and more commonly, button 2 has an XIC instruction which the programmer knows is a normally open instruction. He looks over at buttton 2 and it is not pressed but is "activated" when the button is not being pressed. By separating these terms and eliminating the "normal" position, new programmers grasp these concepts much faster.
@121790tyler
20 күн бұрын
Tell omron plc that
@TimWilborne
19 күн бұрын
The same principle applies, here is nearly the same video but applied to Siemens kzitem.info/news/bejne/kqCFsmRusX6kio4
@121790tyler
19 күн бұрын
@@TimWilborne I know what I was getting at is when you highlight over the xio on omron it says closed and if you highlight over xic it says open
@TimWilborne
19 күн бұрын
Yes, same with Siemens and Automation Direct. But the go look for one and go look for zero principles still work. I can't change the manufacturers thinking but hopefully I can change the people out in the field 😁
@121790tyler
19 күн бұрын
@@TimWilborne I am still trying to learn plcs I have a long way to go the whole true false thing is throwing me off. I understand xic becomes true it goes to a 1 and your output goes to a 1 so the whole rung is true and it lights up green.. But the xio is really throwing me off knowing if it is true or false I know 0 is when it has power and 1 is when it don't but the input has to be false on xio for the output to be true so does that mean the xio is false when it actually has voltage and true when it doesn't 🤔 also in omron does every rung mean its true when it is green no matter if it's xio xic or does that only follow for the xic
@alvieteal4980
11 ай бұрын
Jesus why is there so much random bass in this video
@TimWilborne
11 ай бұрын
Like fish? 🤡
@alvieteal4980
11 ай бұрын
@@TimWilborne no like I had to turn my subs off to watch the video. It’s bad man.
@TimWilborne
11 ай бұрын
Well you did pick one of the older versions...subs?
@alvieteal4980
11 ай бұрын
@@TimWilborne yeah I was watching in my truck
@TimWilborne
11 ай бұрын
😁
@themapmaker5374
3 жыл бұрын
Code the PLC program using Structured Text language, where TRUE = 1, and FALSE = 0. Problem solved.
@homoXhominiXlupus
3 жыл бұрын
Hi man , love your content . This is what i was looking for , BUT i really encourage you to redo the video . Becouse your speech mistake in the video confused me even more. Thanks again btw , don't want to sound ungrateful , you're really helping =)
@TimWilborne
3 жыл бұрын
Yeah right, if I redid every video that had a mistake then I'd never get anything done. I'm an automation guy, not an actor...
@homoXhominiXlupus
3 жыл бұрын
@@TimWilborne Understandable , well thanks any way 😉
Пікірлер: 46