NO vs NC | 5 PRACTICAL and IMPORTANT Points About Normally Closed and Normally Open Contacts

Рет қаралды 163,961

Күн бұрын

✅ Join this channel to get access to perks:
/ upmation
Read the full blog post at ▶ upmation.com/no-and-nc/
We all know how normally closed and normally open sensors and contacts work and how they differ from each other.
But in real-world conditions when we are choosing the instrument switches or other types of discrete equipment for a process, we have to select which one should work with a Normally Open contact and which one should work with a Normally Closed contact.
So, in this video, we'll answer these questions and investigate the real-world application examples of Normally Open and Normally Closed Contacts such as Contactors and relays, pushbuttons, instrument switches, and so on. We also will have a quick look at the NAMUR sensors at the end of this video.
===========================
✅ Please SUBSCRIBE to get notified about the new videos: bit.ly/32mlhu9
===========================
SECTIONS of this video:
0:00 important questions about NO and NC contacts
0:59 different types of discrete signals in the industry
1:27 NC and NO contacts application in a contactor (Example)
2:05 NC vs NO sensor (Example)
3:52 why normally closed contacts should be integrated into stop push buttons?
4:37 NAMUR switches instead of normal switches
===========================
▶ If you've missed our most recent videos, watch them here:
DCS vs PLC: 5 Important Differences between PLC and DCS
upmation.com/plc-vs-dcs/
What is a Directional Control Valve? (5/2 Solenoid Valve)
upmation.com/directional-cont...
How Pneumatic Control Valve Works
upmation.com/control-valve/
===========================
▶ If you want to become a confident PLC programmer, don't miss this free "Siemens PLC Training" course (This course will be continued):
Part 1: Up & Running with PLC Ladder Programming
upmation.com/plc-hardware-con...
Part 2: How to Write PLC Ladder Program?
upmation.com/ladder-logic-plc...
Part 3: How to Simulate the PLC Program?
upmation.com/simulate-the-plc...
Part 4: Motor Start and Stop Ladder Logic PLC Program
upmation.com/plc-program/
===========================
FOLLOW US on other Social Media
👉 INSTAGRAM ▶ / upmationdotcom
👉 TWITTER ▶ / upmation
👉 FACEBOOK ▶ / upmation
👉 LINKEDIN ▶ / upmation
===========================
#NOvsNC #Upmation #AutomationEngineer

Пікірлер: 98

@braincrackz 3 жыл бұрын

I have met so many engrs that practically dont have experience in the field. They dont understand the function of stop button especially when creating a logic in the PLC. But your presentation and explanation will answer their confusing mind. Have a wonderful day

@Upmation 3 жыл бұрын

Hey! Thanks for the input. Yes, that was the reason we have decided to provide such a video to clear things up about the NO and NC contacts. Please let us know if you have any suggestions.

@rickymeadows5176 2 жыл бұрын

You are absolutely correct, I am an Engineering Process Tech for a team of Engineers which basically translates to a Mechatronics Technician with a two-year Associates degree. And it never ceases to amaze me how "little, if any" some of these 4-year degree guys these days, know about PLC or basic electronics for that matter.

@oserebright6505 Жыл бұрын

The type of contactor to be used for the design of this particular High Level switch would be Normally Closed contactor. This is will serve two purposes as the Low Level contactor switch. 1. If there is a damage in the cable, the HMI would identify it as a sign to stop inflow of coolant oil 2. When the oil is filled, circuit opens hence sending same signal to the HMI indicating the tank is filled. But what I really gathered from the selection of the contactor is that it is not just the switching but how to effectively use these contacts to control damages like damaged cables.

@kddk937 2 жыл бұрын

A next level of Teaching... Good Luck. All the best..💓

@athilaldurry5880 3 жыл бұрын

Excellent videos, Many thanks ,upcoming more videos

@luisvarela8638 2 жыл бұрын

Muy buena explicación. Saludos

@SOGUIREL 3 жыл бұрын

Thanks for your efforts. Bravo Monsieur !

@Upmation 3 жыл бұрын

Thanks for watching our video! Merci beaucoup, Monsieur! :)

@MarEngAlamin Жыл бұрын

very appreciative

@yahiaosman8855 3 жыл бұрын

Thank you for this video, and I'm waiting more 💯👏

@Upmation 3 жыл бұрын

You're very welcome! Please stay tuned for new videos.

@sureshkumar-ux2nq Жыл бұрын

Good examples

@shankarsuryawanshi7390 9 ай бұрын

Thank you for your efforts and pain in making this video, marvelous!

@Upmation 8 ай бұрын

Glad you enjoyed it and thanks a lot for watching! Please let us know if you have any questions or suggestions and share this video with your friends and colleagues.

@user-jh2gw1mg7j 2 жыл бұрын

Just priceless content, thanks so much

@Upmation 2 жыл бұрын

You're very welcome and thank you for watching! Cheers!

@MrRumpunch70 6 ай бұрын

Thanks man

@athilaldurry5880 3 жыл бұрын

Excellent videos, Many thanks

@Upmation 3 жыл бұрын

Glad you like them!

@tamilamuthanthangavel5568 Жыл бұрын

Thank u sir

@ringowu6452 3 жыл бұрын

Thank you for the sharing.

@Upmation 3 жыл бұрын

You're very welcome!

@razerimperator231 3 жыл бұрын

Super!I learned the principle of operation OF 3rk1301-0GBOO-OAA2 Siemens DS1-x Motor Starter:)

@Upmation 3 жыл бұрын

Great to hear that! Then we have to provide videos on more advanced topics!

@kresnabayuarraziarifin3956 3 жыл бұрын

Thank you, very usefull

@Upmation 3 жыл бұрын

Glad it was helpful! You're very welcome!

@surendermittapelli3377 3 жыл бұрын

good explanation, waiting for the upcomming videos

@Upmation 3 жыл бұрын

Happy to hear that! Yes, we do publish new videos by mid-November. By then, please share these videos with your friends on other social media to help us grow as fast as possible! Thank you!

@justwatchv 3 жыл бұрын

Thank you. Keep it up

@Upmation 3 жыл бұрын

You're welcome! Please stay tuned for future videos.

@marcinlehmann6890 3 жыл бұрын

waiting for more!

@Upmation 3 жыл бұрын

Hey Marcin! Of course, we'll get back soon.

@thesilentgamer4210 2 жыл бұрын

hello. i really appreciate your presentation. it is simple , direct and easy to understand. I would like to request also a video presentation on how ESD monitoring should be wired and its relation to the system. Thanks a lotttttt.

@Upmation 2 жыл бұрын

Great to hear that! Thank you for watching! I will definitely let the team know of your suggestion.

@mdnezamuddin6219 Жыл бұрын

Tnx

@mohammadbavapoizhithara7132 3 жыл бұрын

hi its really help to learn more about plc and plz do more about plc

@Upmation 3 жыл бұрын

Great to hear that! Yes, we'll restart publishing videos on 17th March. Please stay tuned.

@nguyentuan-ev1zx Жыл бұрын

Thank you very much

@Upmation Жыл бұрын

You're very welcome!

@prasenjitghosh8412 2 жыл бұрын

Most help ful video,plese suggest best book regarding INSTRUMENTATION

@Upmation 2 жыл бұрын

Thank you! Happy you liked it!

@sandyintisel 2 жыл бұрын

amazing

@Upmation 2 жыл бұрын

Thank you!

@badshahengineeringvlogs9718 6 ай бұрын

so nice explination can you please start the plc programing session on youtube please?

@realjohnjones 2 жыл бұрын

Are there normally Closed transistors?

@raufmorad4928 3 жыл бұрын

Thanks for your video,please put your undertitle in another size or color so that we can see more details as shown.

@Upmation 3 жыл бұрын

You're welcome! You should change the subtitle formats of KZfaq in your browser like this tutorial: kzfaq.info/get/bejne/mdWaaM2H3ZnaZKc.html or using this tutorial in KZfaq App: kzfaq.info/get/bejne/rquEn6-Sr6rUd6M.html The format of the subtitles (size, font, color, background, etc.) is not in our hands and you should change them in your own browser or app to your taste.

@sardormuxammadiev250 Жыл бұрын

Hello Mr. HL sensor is NC, in normal level HL sensor contact is open but when level gets high then HL switch contact closed .Am I right? My second question is if HL switch contact is damage or sensor damage then what will be happen? Thank you for your answers

@abhijitraje7462 2 жыл бұрын

I like automation video

@progressfriday1449 3 жыл бұрын

the purpose of the HL sensor, is to ensure that once the oil coolant get to its maximum point the pump should stop. therefore the sensor will be NC switch, once the the maximum point is achieved, the plc send control to open the sensor.

@Upmation 3 жыл бұрын

Absolutely correct! Thank you for the answer! One more reason that we use NC contact for the HL sensor (And it is actually the main reason) is to detect its probable malfunction (cable damage or sensor breakdown) despite the process is running or not. If we have an automatic oil charging system to the tank and the cable is damaged, then the oil will probably overflow and no one gets notified if the sensor is Normally Open. *Generally, remember that the LL and HL sensors both should be enabled and send 1 to the PLC when the level of the liquid is somewhere in between them.*

@amoslois4600 3 жыл бұрын

Dear friend, in 2:20 you assume the LL of the tank ,as a NC switch but is NO switch in fact. (you use the same symbol later as NO).....NOW in 3:10 you assume a NO switch and this time you are right.

@Upmation 3 жыл бұрын

Hey! Thank you for the comment. Let me clarify a little bit more here… An NO contact is a contact that should be OPEN UNLESS it gets excited by an external cause (here is the oil). It means that the normal condition for these level switches is when they are not exposed to the oil inside the tank (whether it is the High- or Low-level switch or it has an NO or NC contact). Please consider that the name is “Normally Open” but it doesn’t mean that it cannot gets closed! So, @2:20 when we assume the LL switch is an NC contact but you see an OPEN contact in the picture, it means that it must be excited by the oil (the oil has reached and passed the NC Low-Level Switch), and it has gotten open. (@2:28 you see it is again closed because the oil is below that.) @3:10 we are assuming another situation with a Normally OPEN switch this time and compare it with a Normally CLOSED switch. We say there “let’s assume the LL is normally open one…” and after that, the oil passes the LL switch and makes it closed. Please watch the video completely and from the beginning more carefully and let us know if you have any further questions.

@sophiawang-bourque8912 Жыл бұрын

I love your videos can you add a video on drawing PIDS

@Upmation Жыл бұрын

Sure we will!

@nareshp4330 2 жыл бұрын

can you explain inductothermal furnace in animation video please

@nikitawbu6192 2 жыл бұрын

Perfecto

@Upmation 2 жыл бұрын

Thanks for your comment and support.

@johnyiu7605 5 ай бұрын

Maybe the main point is that if it is operating normally, it should be closed. So that when there is abnormal operation conditions which would like to be detected in the first place, or malfunction of the sensors/connections, they can be detected at the same time. If it is operating normally and it is open, then there would be problems because malfunctions of sensors or connections can also cause open and it would be perceived as system operating normally. But under this situation if abnormal operation conditions happen, it cannot be detected and the control system will be deceived.

@ericabriguera9211 3 жыл бұрын

Hi, is this also applicable to automatic water pump and can also be operated manually? High level sensor and stop push button are NC while low level sensor and start push button are NO?

@Upmation 3 жыл бұрын

Hi Erica! Sorry for my belated response. Yes, this is applicable for automatic pumping system. Of course this is an example and in different processes we may want to turn on and off the pump(s) with other instruments such as pressure sensors and under certain circumstances (With or without PLCs). Yes, Stop Pushbutton is NC. Low Level switch and Start pushbutton are NO. The High Level switch in automatic process should be NC (as you've said as well) and in manual process (in which we fill the tank manually) you may not need any High Level Switch. Let me know if you have further questions.

@kayitamoses8580 Жыл бұрын

@@Upmation I think for the manual processes you may include some more sensors , for example Extra high and Extra low. This are helpful in a way that if device is run in manual the process can still continue or stop depending on the circumstances

@oleg6517 4 ай бұрын

I suppose the easy principle could be - if you design and alarming device - it should be in NC position during normal operation. And this should be all the time the same.

@GlowingDiscoveries 2 жыл бұрын

Hello, what will happen if there is a broken circuit in the LL sensor? Considering it is NO, nobody can notify the operator.

@Upmation 2 жыл бұрын

Hi there! There could be two scenarios here. First, is an *"automatic"* oil-filling system. Second, is *manually filling the tank* . - Assuming the LL sensor is NO, let's see what happens in the first case (Automatic system): If the LL sensor is broken (sending a zero signal to PLC), then the filling pump should work to fill the tank. As the LL sensor does not change the condition to 1 at some point to turn off the pump, the oil level reaches to the HL sensor. Finally, the HL sensor should turn the pump off. You might say, what if the HL sensor is also broken? Bear in mind that, there could be multiple configurations here depending on our expectations and desire. For example, we can add a middle-level sensor to offer more reliability and at the same time, keep the level of the oil exactly between the LL and HL. or we may solely want to add a timer in our PLC program to turn off the pump after getting a 1 signal from the LL sensor. - In the second case (manual filling): The LL sensor is supposed to send 24 volts to PLC at the normal level. If it does not do so, then something is wrong; whether it is a broken LL sensor or a low level of oil in the tank. Hence, someone should check out the condition locally.

@ArifinSabuz 3 жыл бұрын

Upper Level Switch - NC

@Upmation 3 жыл бұрын

Well done! Thank you for collaboration on the subject! If you could explain why do you think so it was also helpful for the others.

@jaceknows247 2 жыл бұрын

HL is NC because we want it to OPEN upon HL oil 🛢 and shut off power to the auto filling device to prevent overflow...?

@Upmation Жыл бұрын

Exactly as you said!

@paulanderson2450 3 жыл бұрын

would it be a NO so when the level got to high a signal would be sent back to the PLC?

@Upmation 3 жыл бұрын

Hi Paul! Actually, when the process of filling the tank is automatic, the high-level switch should be an NC switch (Sensor). Therefore, as long as the level is below high, it sends a signal to the PLC. And when the oil gets to the high level, its signal to the PLC gets deactivated. The reason is to become aware of any cable damage (or sensor damage) as well as monitoring the fluid (oil) level. The PLC should turn off the automatic filling system when the level reaches high. So we should have an NO low-level switch and an NC high-level switch. Let me know if my answer was helpful or not.

@ajaybisht3301 3 жыл бұрын

@@Upmation Hey, I have a query here. As you said in the video, when main coil energized NO become NC. Lets take an example of LSHH having relay output NO and NC and 24V supply is connected to Level Switch. If I connect NO to the PLC then at normal condition PLC get 1 as input and when High level is achieved PLC get 0 as input moreover when wire breaks in that case PLC get 0. Conclusion: Whenever PLC receives 0 it will stop the motor. (that is Automatic) Another case, When I need to hardwire LSHH with motor directly then I need to connect NO as interlock. These statements are made based on my understanding after listening your video. Please let me know if I misunderstood something. Thanks.. 😊

@Upmation 3 жыл бұрын

@Ajay Bisht Hi there, Ajay! First, let me thank you for watching the video and asking your questions. First of all, I should correct this sentence which you wrote up there 👉 "when main coil energized NO become NC". 👉 Actually, the NO is NO and the NC is NC! When a switch (it does not matter which type; level, pressure, or any kind of instrument switch) has a built-in NO contact and we excite it (energize it by any means) it gets closed, but it is still an NO contact. Second of all, let me simulate what you said again and elaborate more. Let's assume a switch has both a NO and a NC contact and we use it for the HH level of a tank. For High-level, generally we better use a NC contact. It means the switch is constantly sending the 24 volts signal to the controller (PLC) unless the level of the liquid or material reaches to this switch. At this time, the NC contact gets OPEN so that the 24volts from the switch gets disconnected from the PLC and the logic of the PLC should be written so that the pump turns off immediately. The reason that we use a NC contact for a High level switch is that it is the safest way to monitor the signal from this switch all the time (for any kind of malfunction or cable damage). In these cases, we lose the 24volts as well and the same scenario happens (pupm turns off). We'll then check to see whether the material within the tank reached to the high level OR the cable has damaged (for example)? If the material has reached the high level then everything is OK and the process will be continued without interruption and we see that in the HMI and monitoring systems. If the cable has damaged or the switch has some kind of malfunction, we will repair it and will restart the process.

@Upmation 3 жыл бұрын

You may ask how can we distinguish the reason of the pump stop to see if we have to go to the instrument switch location and repair the cable?! Well, if the high level reaches and the pump stops working, then it will restart again after the level of the liquid settles down after a few moments... So there is no problem with the cable or the instrument. As we had explaind in this video, we can use a Namur switch. Normally we use a Level trasmitter AND a high level and low leve switch for having more control over the process. There are other techniques as well...

@vikashranjan6936 3 жыл бұрын

@@Upmation great content 💐💐👍🏻👍🏻👍🏻

@syedaslam2856 3 жыл бұрын

Please send the link for namur switch video

@Upmation 2 жыл бұрын

Hi! We try to publish a video about Namur Switches as well. Please stay with us. Thank you!

@00ffccadobongsili 2 жыл бұрын

NC for HL when sensor or switch sense it was full of oil automatically 1 line will be missing and plc will detect it. Normal Oil level should be NC. NO for LL same as your explanation.

@Upmation 2 жыл бұрын

Thank you for your precise comment and input! That is correct!

@00ffccadobongsili 2 жыл бұрын

@@Upmation keep on sharing knowledge brother. Thanks! New sub here from hvac/r field =)

@Toannguyen-wd5zx 2 жыл бұрын

Some segments in the video are stamped not adjacent to each other

@Upmation 2 жыл бұрын

Hey, Toan! Sorry I missed your comment. Could you please give me an example? Thank you!

@vaseknovak1272 3 жыл бұрын

Switch for high level will be normaly closed.

@Upmation 3 жыл бұрын

Hey! Thank you for your answer! It would be great if you leave a short explanation here for others. Thank you!

@thecrazylooser7 3 жыл бұрын

Thinking the same because a similar reason. If fails, the liquid will just overflow the tank, causing safety hazards around the place.

@Emin3m1986 3 жыл бұрын

2:24 - that’s shown a NO switch 3:15 - and here it’s a NC switch shown...

@rkhrrrmdc3843 3 жыл бұрын

You just get confused because of the illustration, bro. But kindly focus on the situation where and when the LL Switch is triggering. I tried to play it back several times before I understand :-).

@Upmation 3 жыл бұрын

Hey! Sorry, we have missed your comment due to an unknown reason! Please listen more carefully and @2:20 you hear that we say; "Let's assume that the Low-Level switch is a Normally *_CLOSED_* Switch..." and @3:08 we say; "Now let's consider that the Low-Level switch is a Normally *_OPEN_* switch..." We're trying to consider the possible scenarios and give you an idea about each one so that you can understand which scenario is the correct one and what is the reason!

@Emin3m1986 3 жыл бұрын

@@rkhrrrmdc3843 - Mate, you are right. I had to play it few times after you left me the message.

@Emin3m1986 3 жыл бұрын

@@Upmation - Yeah, sorry you are right. I though that the iilustration was opposite to what you was saying, but I was wrong. I appologise and thanks for taking your time to deal with me. I hope if are any other "rubber heads" like me, will see my comment and yours and MDX reply. Thank you very much for doing this kind of videos! This are very informative!

@jsmith7310 2 ай бұрын

This all comes under the heading " Fail Safe"

@bitebonumbere1426 3 жыл бұрын

Please when are you going to populate your KZfaq channel with hundreds of videos?

@Upmation 3 жыл бұрын

Hey Bitebo! Thanks for your interest in our videos. We'll restart publishing new videos by mid November.

@bitebonumbere1426 3 жыл бұрын

@@Upmation Please how frequently are you going to publish? Daily? Weekly? Monthly? Yearly? Also, how can I financially support the sustenance of your channel? Do you have a patreon account?

@Upmation 3 жыл бұрын

@@bitebonumbere1426 We'll publish two videos per month. Unfortunately, we do not have a Patreon account yet.