Visual programming is also used a lot in plc programming (Siemens S7/TIA, Mitsubishi MELSEC, etc..).
Programming visually is usually called FBD or LAD. We use often FBD for simple logic. It's easy to read, even for inexperienced maintenance guys. LAD is a no go for me, but it seems a lot of guys still like it.
http://szirty.uw.hu/lang/Siemens_TIA_FBD.png
As long there is a simple and clear code structure, it is a good thing.
Today, special since Siemens made SCL (kind/like of Pascal for PLCs) usable and in there new IDE (old was Step7, new is TIA), we use it also a lot.
Today it's even possible to mix FBD/LAD and SCL. So you can make al simple logic in FBD or LAD, and then calculate things in between in a SCL network.
As user of both worlds in my job, I can say both worlds have a right to exist. It's just like is C better than C++ or is Python even the most best ... is a car better than a bike .. is a house better than a tent ..
>As long there is a simple and clear code structure, it is a good thing
I've seen sprawling, massive ladder logic jumbles that made no sense and were completely undocumented before. Once visual-style plc things reach beyond a certain level of complexity, if they are undocumented they can be a nightmare to use.
I don't know if this says more about the medium itself or that a lot of PLC guys just don't know or were never taught proper standards to follow in writing their code. Either way I've seen a lot of really bad PLC code.
Sure, I should have maybe made my point clearer and say PLC programmers in my experience are often guys with no programming background who have an Associates in automation technology or something similar from a local community college.
They have often not been taught basic things like don't name a variables or identifiers that have no significance like 'b123' and are in a workplace where as long as the lines are running properly nobody cares. There are leagues of difference between what I would consider a pretty messy codebase at say, some B2B enterprise software company, and a large codebase maintained by people who actively don't know how to program for lack of a better description.
As you can imagine, I've seen also a lot more or less funny ladder logic.
And yes is true, most plc programmer don't have a "just software" background and yes a lot of plc software is not super pretty but with the old IDEs it was also not so easy.
there is some pretty solid theory on how to translate between the kind of diagrams statebox uses and digital circuits. In fact we are doing some experiments with direct diagram to wafer (chip) translation using LibreSilicon http://libresilicon.com/
this is certainly not a done thing, but something we'd love to work more on in the future
It was possible since Simens Step 5 (since late 70s) to change your view between FBD/LAD and AWL. But AWL is just like Assembler, so .. yes. In old machines (we still have about 20 machines with Siemens S5) sometimes it's a must to use AWL.
Translate an IF statement you need to add jumps, so it's not really the same code.
Also for ex. the very simple Siemens LOGO controller has a simple software to program it. But if you use FBD, it's just possible to use a tag once. So if you need a tag multiple times, so you have to draw lines from the single tag. Even for super simple stuff it get's messy super quick.
Programming visually is usually called FBD or LAD. We use often FBD for simple logic. It's easy to read, even for inexperienced maintenance guys. LAD is a no go for me, but it seems a lot of guys still like it. http://szirty.uw.hu/lang/Siemens_TIA_FBD.png
As long there is a simple and clear code structure, it is a good thing.
Today, special since Siemens made SCL (kind/like of Pascal for PLCs) usable and in there new IDE (old was Step7, new is TIA), we use it also a lot.
Today it's even possible to mix FBD/LAD and SCL. So you can make al simple logic in FBD or LAD, and then calculate things in between in a SCL network.
https://planken.org/images/screendumps/201408-tiav13-network... (the only (not so great) ex. I found)
As user of both worlds in my job, I can say both worlds have a right to exist. It's just like is C better than C++ or is Python even the most best ... is a car better than a bike .. is a house better than a tent ..