If you rewind back to post #7 you'll find an engineer who just listed off several reasons, most of which not regurgitated from a propaganda pamphlet.

Read post #7 again. It's all about PLC companies being more reliable, having better products and better support ... even being so good that they never go under (unlike non-PLC companies).

 

Starting in the early 80's I retrofitted a number of factory assembly lines that had relay logic panels for the system controls, the cost of the PLC was extremely minor compared to the overall cost of the retrofit, the savings came when maintenance could trouble shoot with ease and prevent very costly down times, so I would say they did the job asked of them at considerable savings.
Actually one of the biggest areas where down time was saved was the implementation of DC over AC coils and particularly solenoids where down time replacement was high.
As to support, It has been excellent from Mitsubishi Canada and US.
Max.

 

PLC is just a box with an MCU inside. The MCU is oversized for the task to support rather clumsy PLC software. They're overpriced - the manufacturer gets very good margin. Imagine, instead of PLCs you were given a bunch of boxes with microcontrollers inside, which, unlike PLCs, would be created for the specific task, the software would automatically tune-up and configure itself. Everything would cost much less, and you would have less work commissioning it. It is possible (technically and economically).

Specific task, that's the hinge. PLCs are configurable to serve a multitude of tasks, with a common form factor. That's why they have become so vastly important in transforming industry. Systems performing specific tasks have seen tremendous growth and will continue that tragectory. Don't make the engineering mistake you alluded to earlier and choose the wrong system for the application. You'd be wrong if you suggested that the popularity of PLCs were due to engineering ignorance

 

Read post #7 again. It's all about PLC companies being more reliable, having better products and better support ... even being so good that they never go under (unlike non-PLC companies).

No it wasn't.

 

Oh @NorthGuy I believe i said something like "why would anybody use a truck, when they could use an engine for the same purpose? Because they would have to build a truck around the engine, at which point it would have made more sense to just buy a truck."

A truck can do much more than an engine - it can run, carry loads etc. In contrast, PLC doesn't add anything new that MCUs cannot do - it simply changes a form factor, as if you would enclose the engine in a big metal box. It still would be an engine, not a truck, only in a box, and would be much more difficult to build trucks with.

 

Yes, i have. I love my arduinos, for my hobbyist endeavors. If you could teach me how to suck the programming out of an arduino that someone else programmed, add a simple instruction linked to a new digital input, and then monitor the status of I/O in real time to verify the new sensor is doing its job, that would be awesome.

I haven't try that function yet, just thought that it is possible, refer to these:
Topic: Downloading/Reading sketches from the Arduino?
Topic: Automatic disassembling (Read 9075 times).

I have a friend worked in a BIOS company, he play with the Embedded Systems and Microcontrollers more than me, I will ask him to make sure is it possible tomorrow.

 

A truck can do much more than an engine - it can run, carry loads etc. In contrast, PLC doesn't add anything new that MCUs cannot do - it simply changes a form factor, as if you would enclose the engine in a big metal box. It still would be an engine, not a truck, only in a box, and would be much more difficult to build trucks with.

uC can do the thing as PLC can do, but it just for case by case and it is for a small group of people to use, but the PLCs are suitable for most of the people to learn, to use, I saw a company did the the thing as you said, they developed a 8051 type PLC module in several years ago, it's quite cheap, the price less than 70$, but I can't find it now.

What do you think as below?

1. uC (8051, Pic, Atmega) Arduino
2. uC(8051, Pic, Atmega) PLC.

 

I haven't try that function yet, just thought that it is possible, refer to these:
Topic: Downloading/Reading sketches from the Arduino?
Topic: Automatic disassembling (Read 9075 times).

I have a friend worked in a BIOS company, he play with the Embedded Systems and Microcontrollers more than me, I will ask him to make sure is it possible tomorrow.

You have to remember the context. You should ask you electrician buddy, not your bios engineer buddy. The answer should be clear to you.

 

A truck can do much more than an engine - it can run, carry loads etc. In contrast, PLC doesn't add anything new that MCUs cannot do - it simply changes a form factor, as if you would enclose the engine in a big metal box. It still would be an engine, not a truck, only in a box, and would be much more difficult to build trucks with.

The point should be obvious. An engine performs the same basic task, but housed in a truck, has certain characteristics, opposed to being housed in a airplane, which has certain characteristics. You choose the form to perform the task at hand. In your previous post you suggested numerous dedicated black boxes over a centralized generalized black box. Without referring to the application, how could make such a determination?
Given your logic, why hasn't the Arduino taken over the world?

 

You have to remember the context. You should ask you electrician buddy, not your bios engineer buddy. The answer should be clear to you.

No, your are wrong, I think you didn't see clearly, he is playing with Embedded Systems and Microcontrollers, so he knows more about arduino, AVR, ARM ..., he even modified the screen of a tester for resistor, coil, bjt, and ESR for capacitor, the function are the same and the picture as below, but it is a different type.

 

You choose the form to perform the task at hand. In your previous post you suggested numerous dedicated black boxes over a centralized generalized black box. Without referring to the application, how could make such a determination?

That's right. It is impossible to design anything without knowing the application. The point is PLCs are much more widespread than their qualities warrant. That is mostly because of government regulations and prevailing engineering mentality, both carefully crafted to favor PLCs and integrated solutions alike.

Given your logic, why hasn't the Arduino taken over the world?

Arduino is another form factor, which also has overhead, but much less than PLCs. I'm mostly talking about bare MCUs. They did take over the world. Only tiny fraction of them is installed in PLCs (or Arduinos for that matter).

 

A truck can do much more than an engine - it can run, carry loads etc. In contrast, PLC doesn't add anything new that MCUs cannot do - it simply changes a form factor, as if you would enclose the engine in a big metal box. It still would be an engine, not a truck, only in a box, and would be much more difficult to build trucks with.

So if i just put a uC (or even an arduino) in an enclosure, I'd have an ethernet-ready PLC with analog I/O and enough I/O for an entire soda bottling line? I'd have a PLC that can talk to my existing touchscreen panel using its proprietary protocol? I'd have something that i can guarantee to my customers will have tech support that will live on after the potential end of my company?

I already know your answer must be "yes", or else you'd have to concede. And you aren't about to do that, so I will. You are right, and the whole of the automation industry, including myself and more than a handful of some of the most brilliant engineers I've ever met, are a bunch of idiots. This whole time we've all been so easily duped by this lot of flim-flam men into buying a bunch of "features" we don't need (despite the fact we actually use them). This whole time we could have been using MCUs inside of enclosures with no need for support circuitry or software. I feel quite stupid now.

I do however take consolation in knowing that we haven't been duped as bad as PC owners. At least we didn't pay for such ridiculous things as monitors and HDMI ports. At least we didn't fall for that whole "antivirus" hullabaloo. And hard drives; sheesh, what kind of moron pays for a hard drive?

 

That's right. It is impossible to design anything without knowing the application. The point is PLCs are much more widespread than their qualities warrant. That is mostly because of government regulations and prevailing engineering mentality, both carefully crafted to favor PLCs and integrated solutions alike.



Arduino is another form factor, which also has overhead, but much less than PLCs. I'm mostly talking about bare MCUs. They did take over the world. Only tiny fraction of them is installed in PLCs (or Arduinos for that matter).

So what form factor do you suggest would best replace the overabundance of PLCs

 

"Antivirus" hullabaloo? I've heard a story that Iranians were using PLCs to control their centrifuges, and someone broke in, manipulated PLCs and destroyed centrifuges. Similarly, someone can break into your "etherned-ready PLC". How's that for the safety of the customers? Do you have all the antiviruses in place

 

So what form factor do you suggest would best replace the overabundance of PLCs

You choose the form factor based on your needs. I personally think it is good to have a diversity of forms - things made differently by different companies - this gives customers freedom of choice.

 

You choose the form factor based on your needs. I personally think it is good to have a diversity of forms - things made differently by different companies - this gives customers freedom of choice.

So if I choose a PLC as a solution, am I wrong.

 

So what form factor do you suggest would best replace the overabundance of PLCs

Well i thought he was suggesting arduinos or other proto boards (maybe just uC ICs ). But given his vague reply now I'm clueless as to what his beef is or what his proposed alternative is.

You choose the form factor based on your needs. I personally think it is good to have a diversity of forms - things made differently by different companies - this gives customers freedom of choice.

Congrats, you just described PLCs. That's exactly what PLCs offer. Everything from sub-$100 digital bricks to complex PACs and DCS networks.

 

No, your are wrong, I think you didn't see clearly, he is playing with Embedded Systems and Microcontrollers, so he knows more about arduino, AVR, ARM ..., he even modified the screen of a tester for resistor, coil, bjt, and ESR for capacitor, the function are the same and the picture as below, but it is a different type.

View attachment 98910

but the discussion is about PLCs and substitutes. Do we need a bios engineer to run this thing or can an electrician use it as a troubleshooting tool?

 

"Antivirus" hullabaloo? I've heard a story that Iranians were using PLCs to control their centrifuges, and someone broke in, manipulated PLCs and destroyed centrifuges. Similarly, someone can break into your "etherned-ready PLC". How's that for the safety of the customers? Do you have all the antiviruses in place

Way to deflect, artful dodger.
Anyway, you base your appraisal of PLCs on the competence of iranians?

 

Congrats, you just described PLCs. That's exactly what PLCs offer. Everything from sub-$100 digital bricks to complex PACs and DCS networks.

There's a difference between form and function.

"sub-$100 digital bricks". This can be done with small 50-cent MCU plus few discrete components. Will cost you $5 manufactured and shipped in small quantities. Takes few days to manufacture, including pre-programming of the chips. It will take less space and will be more reliable because there's a much simple design. What is the advantages of the "sub-$100 digital bricks" over this?