Holding Circuits in Application - Water Tank Level Control Circuit

An example of two holding circuits in use in a control circuit that tank maintains a level in a water tank.

[@thebestpaintballer]

I haven't had any PLC courses in 7 years and suddenly need it at work. These are great to get back into things

[@iStoneCarving]

To catch up with your speed is for me a challenge really but it worth it a try. When I found I could understand more early today I felt proud. Thanks for your explain.

[@Knieghtz]

You are a great instructor, thank you for the video.

[@larsexplains3086]

Thanks for the Props! I LOVE what I do.

[@amir.k6747]

Great video! Another with a complicated application!

[@larsexplains3086]

O LOVE Complicated. You've got to always push your abilities and challenging oneself with complicated tasks is empowering and rewarding.

[@rodroller6634]

Making it so much easier to understand. Thx

[@larsexplains3086]

Thanks Rod. I'm so happy I could help! and get this stuff into your brain smoothly.

[@TheKyleee18]

You certainly know how to convey information to someone new to the subject. Kudos!

[@larsexplains3086]

Thanks for the awesome feedback! I love educating!!! THe holding circuit is amazing! It's a one-bit computer and so much more. Any topics you'd like to know more about, pass them along and I'll see if I can fit in a vedo. Thanks Kyle!

[@SamirMishra6174]

Brilliant Sir, you have a gift for teaching, you understand the subject very well.

[@ducaalea1918]

Excellent video. Amazing!

[@larsexplains3086]

Yeah I know 🤣 Thanks Ducaale A!

[@fenghao9736]

I do like your courses, Sir! Extremely helpful particularly for beginner to understand ladder sooner. Hope this will help others know your channel.

[@larsexplains3086]

Thanks Feng! I love to hear I'm doing good job and especially to hear you're learning

[@larsexplains3086]

Thanks for the Props!

[@learninghome5396]

Greaaaaaaat ! If you understand it enough, you can explain it well.

[@larsexplains3086]

Thanks Learning at home. I totally love this stuff! I guess that's why I understand it. J'apprécie votre commentaire!

[@jpikspiks2067]

Thank you sir, I'm studying again on PLC since I want to do a career shift from telco indistry to automation. I do have a rough idea on ladder diagrams since I did use Festo pneumatics during college as part of a 1-semester course. Your course are really helpful on my reviews. 😁

[@larsexplains3086]

Great news Jpiks! PLCs are super powerful and cool machines! They are used in many many industries around the world! It a great skill to have. Good luck with your studies!

[@muraleedharanpaloran1712]

Excellent way to teach 👏

[@larsexplains3086]

Thanks for the kind support Muraleedharan. I do love doing it!!!!!!

[@nghieu2989]

Good explanation

[@fernnn831]

This video is very useful for me very good explanation make me understand clearly Thank you so much

[@larsexplains3086]

Great news Fernnn! I'm happy to hear I could help

[@phild1562]

Great video! Can you possibly make a video to include low and high level alarms with the relays

[@Durga189]

Great effort

[@larsexplains3086]

Thanks for the suppoprt Gadadasu

[@aidanhay3744]

omg, this saved me thank you

[@larsexplains3086]

awesome Aidan! So good to hear Dude!

[@zuhairabakar]

Tq sir. This short course really helps me

[@larsexplains3086]

Awesome! So good to hear Zuhair!

[@odhiambootieno8227]

Good work

[@atulrao1382]

In this video you give excilent Logic for practicing programme in plc

[@larsexplains3086]

You're most definitely correct! This logic can be used for PLC's. These Ladder videos are designed for a controls course in the program Electromechanical Engineering at Humber College. In this course, students build ladder circuits with relays and other inputs and outputs. It gives the students a tangible understanding of how control circuits work and allows them to see the logic in the wiring and the actual components. It's a preparation course for several PLC courses we have in our

[@camc694]

Can you do the same problem with flip-flop relays instead of float switches?

[@musabarmeh6991]

Thank you so much, Sir you are such a great teacher. I have issues holding the upper float switch because during implementation as soon as the water goes below the upper float switch it closes again and again hence the pump comes ON and OFF frequently. I want the pump to stay OFF until the water level goes below the lower float switch otherwise it is a problem. Is it possible to hold an unenergized coil?. Thank you

[@KrizzNANDU]

Good content

[@larsexplains3086]

I'm happy to know your getting something out of my videos!

[@dalwindersingh9455]

Wonderful

[@larsexplains3086]

Thanks Devon!

[@craigrmeyer]

This is fascinating. I feel like I just found Atlantis. Here we have a way to think through controlling whatever, and without a single line of esoteric C code that no one will even understand in six months, including me.

[@anchitrana4306]

Very interesting

[@larsexplains3086]

Great! I'm glad you got something out of the video. If you have another topic or question about Ladder Logic, pass it along.

[@raselrana9528]

Good. Control. Sestem

[@user-cq5db9nt8k]

Can someone post a wiring diagram for this, does it require 4 relays or will 3 work? also I'm a bit confused on how the connection between the relays will be done to create the hold. I have a very similar system but I just cant get it working 100% the pump always switches on and off at the wrong time lol

[@ikbelhammami5525]

How about I'm having NC sensors for H and L levels as well I need an indication light for the error if the sensor indicate the water level H and the low level low in the same time.

[@larsexplains3086]

This is a little complicated and I need more information to be able to answer you. I'm not sure what you mean by the error of the sensor. IT is either high or low. Generally error is associated with analogue sensors. Can you email me with more specifics? [e-mail]

[@ikbelhammami5525]

@@larsexplains3086 Sure and I truly appreciate!

[@ikbelhammami5525]

@@larsexplains3086 I already sent :) can you check your spam folder.

[@deancook2123]

Hi great video can you just confirm something Regards the low level switch sensor is it normaly closed in normal state until the relay is energised- I'm confused Regards the staus of it as you say it becomes open thus de- energisising Relay 2 ??? So Surely it must be normaly closed before ???

[@larsexplains3086]

Hi Dean. I did a video response to your question. I thought it important to unpack the terminology and needed a whole video to do that. This link will open the video: ca-lti.bbcollab.com/recording/1645b1b8bd6b4e1e84196a645dce0d9d

[@deancook2123]

@@larsexplains3086 thanks Lars 😊

[@deancook2123]

@@larsexplains3086 you're video explained it perfectly - its just a switch regardless of its state it moves each way i understand Great stuff Love the videos, I've only just come across them & find you're teaching easy to understand Again thanks 👍

[@evanturner3753]

@@larsexplains3086 I have the same question as Dean, but that link no longer works....

[@ifrekerobert9299]

I want a circuit of a pump that runs for 20mins, stop for 2hours and continue the process again using a timer

[@trillxsteelo]

oh dear God i understood all of that

[@larsexplains3086]

Oh my! I had a good laugh reading that!

[@Perfect_x_vip]

Hey Why R1-1 used

[@joewebb4836]

SO IF THE PUMP FAULTS HALF WAY, YOU CLEAR THE FAULT, YOU HIT START....WHAT WILL HAPPEN ?

[@larsexplains3086]

What will happen depends on what the fault of the pump is. If is a mechanical or even an electrical fault with the pump, then to “Clear” the fault, then a diagnostic must be run on the pump to see where the fault is coming from. In this case, the fluid may need to be removed from the tank. To empty the tank, the drain solenoid (which is not part of this video but can be seen in the diagram labeled “D” for drain). Once the tank is empty a diagnostic can be performed on the pump to assess where the fault is. If it needs to be replaced, then it can be because the liquid has been drained. Your use of the word “clear” indicates it may be a programing issue, but you mentioned the fault was with the pump and did not indicate it is in the control circuit. Just in case you were asking if the fault is a control issue, I will address that as well. A control or programming fault occurs when either a signal that does not typically happen becomes active or a physical breakdown. In this simple control circuit such a fault would come from either the Upper Float Switch activating before the tank is full, or an operator presses the Stop button before the tank is full. The other type of fault could be a physical issue with the circuit where a component (relay, wire, power, contact,… ) was damaged. IN this case, the tank should be drained, and a control system diagnostic should be run. If the fault was from the upper float switch being activated or the stop button was pressed in error when the tank was half full, then pressing start a second time would not re-start the system. This is because the lower float with is in its active state and the NC contact R2-1 is open. Also, the holding circuit R3-1 contact will be open because it forgot the liquid was below the lower float switch, There for pressing start will not start the pump. There are several options to modify the control circuit to allow for faults like this so that pressing the start again will re-start the filling process. The re-thinking of that control circuit starts with first considering where exactly the fault came from. I only discussed a few options of where the fault came from, but there are several other reasons why a control system and or the pump itself may fail. Targeting each reason why a fault will happen is the first step to re-designing the control circuit or the pump mechanism itself. If you can give me an example of where the fault came from exactly, I can suggest options to re-design the system to have a ‘fault-reset” as well as having the pump re-start the filling if the start is pressed again. A kind note: Typically, when people write using all capitals, they are showing that they are somewhere upset and or showing aggression, frustration and/or possible anger. I do not get the sense that that is where you are coming from, but I thought I would give you some kind advice that some may read into that and assume you were upset in some away and or attempting to show aggression. Regards,

[@Pgan803]

I think it is easier to visualise if you do a Flow Chart YES/NO type, then easier to do a Ladder PLC

[@larsexplains3086]

Food for thought. Thanks for the feedback.

[@user-xd9cy2rl9x]

diff from i learned at polimas

[@andyblackpool]

I can't understand why this circuit has been devised so complicated when it only needs one relay with two sets of N.O. contacts to do the same thing?

[@hvacskull]

Because your mind is closed, Plc is currently used in the most diverse segments in the industry, the idea here is not electrical commands, but rather ladder programming

[@Perfect_x_vip]

For holding.

[@larsexplains3086]

Hi, great question. I think the best way I can answer this is with a video I did on holding circuits. Have a watch and I think this will answer your question. kzbin.info/www/bejne/p5DCk2t4qbKrq6s

[@anwarulhaqsaleemi5106]

After water reaching upper float switch the pump Stop But it will start again as soon as the water consumed a little and UFS deactivate again

[@larsexplains3086]

Yes, exactly! Youi are 100 percent correct. I see you have a good understanding of Ladder Logic. In this simple control circuit, it is assumed that the tank needs to remain full if some liquid is removed. If the application did not require that, then that is a prefect example for another holding circuit. I get the sense that you have the understanding to add that holding circuit into this circuit so that the tank will not full if liquid is removed. If you would like advice on how to do that, I would be happy to advise you. Wishing you all the best!

[@incognito6751]

This makes no sense despite how many times I rewatch it

[@larsexplains3086]

Happy day Incognito! I'd likje to help and would love to get some feedback from you. I need to know what you don’t know so I can tell you what you need to know. Before we move forward, I think the best thing is for you to watch a video I did on how holding circuits work. kzbin.info/www/bejne/p5DCk2t4qbKrq6s Then you can re-watch this video and try to imagine what's happening with the liquid. In this application the holding circuits are used as memory latches. They remember the event of the tank being empty or the tank being full.

[@joshbennett7854]

R1 was wayyyyyyy faster then rc