What is Ladder Logic?

▶ Check out the full blog post over at

==========================

If you are involved in any way with industrial machinery, you almost have to have heard of ladder logic.

Since there are almost never ladders involved, it probably doesn’t make a lot of sense that we call it that, but the reasons for the name are buried in the history of automatic controls.

At one time, automatic systems were controlled with relays. Relays are electromechanical devices and fail quickly as the mechanical parts wear out and the electrical parts are destroyed as the electricity they switch burns away the contacts.

They are big and use lots of electricity, generating lots of heat in the process.

In order to understand why we call it ladder logic, you need to look at how we document relay logic controls.

The actual “ladder” was the drawing of the control logic, an illustration of how the relays were wired together.

Even today, a lot of the conventions that led to “ladders” are still in use, and I will use a recent example drawing to illustrate this.

==========================

Missed our most recent videos? Watch them here:

=============================

To stay up to date with our last videos and more lessons, make sure to subscribe to this YouTube channel:

=============================

=============================

#RealPars #ladderlogic

[nishyu]

This is what i was hoping to find when i was searching for a basic video!
the nomenclatures and basic jargon was explained with the available features!
this is the kind of video which is exactly needed for beginners.

[laurentiucosma]

I love you guys! You are literally saving my life for my PLC exams!!!!❤️

[emuskk]

Our syllabus was willed with outdated crap as an electrical engineer i appreciate what you are doing thankyou very much

[jakubhavlicek]

You guys are the best. I really appreciate the effort which is required to create these videos...

[mtridgrl]

Aside from rushing, I really appreciate these videos... I recently graduated but haven't been hired in this field that I wanted to pursue since school. Now that I have the chance to do so, some of the knowledge I had has slipped away x.x, so thanks RealPars for these videos. I am forever grateful. 💖

[UmarFarooqVeerapur]

One of my favourite channel in entire YouTube ❤

[manny]

I am having flashbacks of having to learn this stuff for my engineering program...all I remember is that I didn't really get it...hehe...well...in the end I got my degree...

[AdrianHertz]

Vegeta: "He is speaking the languague of gods"

[ChasingHopeVlog]

Thanks for the video. I'm taking detailed notes on this.

[arasothman]

thank you very much...i love you RealPars

[gvenagas]

If I understand correctly, between the physical switches and the make and brake symbols of a plc, the bits mediate. The bits have an initial value of '0', so it coincides with the normally open state of a contact, while the same is not true of the initial closed state of a contact in the ladder diagram, which for any contact to open, the input bit must change from 0 to 1

[ardentdfender]

I greatly enjoyed this video. Ladder Logic is the underlying basis of all the automation programing we deal with in every program whether it’s its with Rockwell Automation products or Citect Software. I didn’t start off as a programmer but cane from Operations and being a Technician. I’ve been in automations 5 years now but it’s not only thing I do as it includes Field Service and commissioning of OEM equipment also. But, I’m going to also admit, I’m very slow at reading Ladder Logic as it has to make sense as I’m reading it. My Senoir coworker just zips through it scrolling up and down at lightning speed and I never get how he can read it all so fast. The simple symbol elements I can more easily get. But it seemingly gets very complicated to read and understand when it has the Function Block elements in the ladder to read or understand what exactly it’s saying as well how the bit is programmed especially in ControlLogix which is easier to understand than PLC 500 or the dinosaur of PLC 5. Elements like MOV, LIMS, SQC, EQL and many others as there is a whole chart for all the other ladder rung elements. I honestly think a whole series of videos for ladder logic on how all the common advance Function elements each work or is “read” in a ladder similar to this video could be immensely helpful in learning to read and understand Ladder Logic. My coworker always tells me it’s easy and I know he thinks it is and probably is, but when your not quite clear what it’s even saying as well how that bit is programmed, your not sure how to even read what that programmed bit is saying or doing. Love the video though.

[binusnbayothegrey]

Thank you realists. I cannot thank you enough

[disrael]

Great great beginner explanation, need more such informative videos

[Ronaldo-ybnt]

You are the best Automation Engineers all over the World

[kiranchoudhari]

Thanks for making my profession very interesting, , , real Pars

[fern]

Very clear explanation...it's more than a school 👍👍

[ЕвгенийПривет-кч]

The video content is so excellent, congratulations

[kevinhuffman]

I work in a large industrial plant, let me tell you these guys are legit! They’re on point! It’s hard to find solid training for this industry these days. I highly recommend subscribing.

[kistamganesh]

Yeah it's great.
And I received a lot of information from this channel. And if you provide subtitles then it will be out standing.