make PLC from AVR

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Hi all,

I need help for my project. My project is to create "PLC from AVR microcontroler".
I need advice which AVR microcontroller i shall choose for that project and what kind function i must implement to AVR so it operate like PLC.
My fried had suggested me to choose ATmega32 or 8 but i need another suggest before i decided it so PLEASE HELP me!

thank's

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Depends on what you want to control, the process of control, and any outboard equipment.

A plc is really designed to basically be built off the shelf, to do just about anything. I have a Modicon microPLC running my sprinkler system right now, until I design the module for my home automation system.

Also, traditionallly the big PLC's use micro processors, not Microcontrollers for their 'brains'. Since Microcontrollers contain everything(uarts, interrupt controllers, all I/O), they are not a reall good choice for something that must be doing a very heavy workload where several devices share the load.

Unless the professor has assigned this, which would mean that it probably has been done before, then you might want to re-think your project a little. I will conceede, though that a bootloader in the AVR could be an option as the micro would be able to self program itself.

Good Luck

Jim

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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marteenjwiil wrote:
I need advice which AVR microcontroller i shall choose for that project
Why is it that you kids always want to do it backwards? You first gather your requirements, make an initial estimate of the needed system resources, and then you select an MCU for prototyping. That selection includes to study the datasheets of a bunch of different MCUs.

During prototyping you might figure out that you can or need to change to another CPU.

Quote:
and what kind function i must implement to AVR so it operate like PLC.
Isn't it your homework and part of your project to study that, instead of asking for a canned solution and hand holding?
Quote:
PLEASE HELP me!
Stop whining. Don't you have any pride?

Stealing Proteus doesn't make you an engineer.

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Your Prof/TA should teach you the engineering process: requirements definition, verify with stakeholders, develop and rank solution alternatives, select tools, build, test. Coding is maybe 20%.

You could just start coding, which is what many believe the task involves, including secondary education.

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Steve/Arnold
Good points, I did overlook that this is possibly a class sleeping/skipping engineer, but I have been asked to curb my cynacism(spelling :roll: ).

At the same time though I kinda explained the hurdles the OP is faced with on this one.

Jim

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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My view of a Programmable Logic Controller (PLC)...

A PLC is designed to be broad in its application. The initial inception of the PLC came from the automotive industry, in order to facilitate rapid product change-over. A PLC is flexible, and able to capture, process and output a broad range of I/O in a wide range of applications, including general Purpose I/O, analog data, remote communications and other forms time critical data.

A PLC uses a language that is easy to learn and understand, usually based upon conventional "Ladder Logic " that predates the PLC itself. Ladder Logic tends to represent how the control system would be configured if actual (real) relays were used.

A PLC uses enhanced functions in software that represent the hardware equivalent.

The advantage of the PLC over the real "Hard-Wired " relay logic is that, the PLC function blocks can be changed with a minimum of physical labor and/or effort - without the need to re-wire the physical hardware.

The PLC is designed for the industrial environment. That is, the PLC is usually rugged and robust to handle the abuse that will be encountered in the industrial environment - meaning, the I/O is well protected. The PLC power supply is substantial enough to not only power the PLC chassis and the typical I/O and other hardware modules associated with a particular PLC family, but in a lot of cases, the external devices may also be reliably powered by the PLC main power supply.

Lastly, the PLC is designed to work in a wide range of environments and the temperatures that are associated with those environments.

The key features then, of a serious PLC are:
(not necessarily in order of priority)

1. Flexibility.
2. Reliability.
3. Ease of use.
4. Ruggedness.
5. Standardized programming environment.

No embedded device would be considered a serious candidate in the PLC arena, unless/until it can meet the above conditions.

EDIT:
With current day PLCs, the system is as much about communications as it is looking at input, processing & controlling hardware.

There is the newer Modicon PLCs - all about communications. There is ControlLogix - all about communications.

While the input, processing and output are well defined and have been implemented & employed for quite some number of years, it is the communications aspects of the PLC system that has taken the front & center stage of the PLC audience.

So, any PLC that is going to be a success, must include facilities for such communications, such as Profibus, Device-Net, DH-Plus, RS-485, DH-485, RS-Networking, Ethernet, as well as legacy RS-232 and other simpler communications methods.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Carl,
As always you give VERY detailed responses. YOur explanation was what I was thinking, but tried to keep short. Well done!!

Jim

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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Quote:
I need advice which AVR microcontroller i shall choose for that project and what kind function i must implement to AVR so it operate like PLC.
Please define what do youmean by PLC. IF you want 8 relays and 8 optocoupled inputs, there's nothing simpler. See the ULN2803A datasheet for a good relay controller and you can use normal input pins for most optocouplers with pullup resistors. The ladder-logic to processor compiler is somewhat more difficult.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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daqq wrote:
IF you want 8 relays and 8 optocoupled inputs, there's nothing simpler.

But this doesn't constitute a P rogrammable L ogic C ontroller (PLC ) in the context as used in a conventional sense.

When the term PLC is used, the first thought that should come to mind is a device that meets a set of standard practices to implement this PLC device.

Yes, a device that has 8 optically coupled inputs and 8 relay outputs is programmable, it does use logic to solve problems and, it is a controller, to be sure. But to say that this is a PLC, by current day standards is incorrect. There are certain criteria that need to be met for it to be truly defined as a PLC - Else, your wrist watch is a PLC, your TV remote control is a PLC, the PC computer itself would be considered a PLC.

A controller with 8 inputs and 8 outputs in no way meets anything close to the criteria necessary for it to be classified as a PLC. This simple device might be a distant cousin, but a PLC, it is not...

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Quote:

1. Flexibility.
2. Reliability.
3. Ease of use.
4. Ruggedness.
5. Standardized programming environment.

Quote:

There are certain criteria that need to be met for it to be truly defined as a PLC - Else, your wrist watch is a PLC, your TV remote control is a PLC, the PC computer itself would be considered a PLC.

1. My watch wraps nicely--flexible.
2. It has run for years and years without a problem, and on the original battery.
3. The time, date, and stopwatch functions are indeed easy to use.
4. It still works after being in all kinds of wet and cold weather, and after being run over by my bicycle.
5. Hmmmm--it IS programmed the same way as other Timex Ironman/Triathlon series, and many other Timex models as well.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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theusch wrote:
My watch...

Your simple little time display is nothing more then a tightly controlled state machine - with no flexibility, beyond it's 10 to 15 (a couple dozen, at most) allowable states.

And, you can't easily alter it's functionality beyond those pre-programmed states already in existance.

So, your watch is not really programmable as, you can't program it to be a watch today, and then a completely new device tomorrow. Other then a few switches and display segments of dedicated purpose, it has no real I/O to speak of.

And, quite frankly, I've never had a digital watch that worked worth a damn! They certainly aren't what could be called reliable.

Doesn't even come close to qualifying.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Somewhere on the internet I read that someone had created a "PLC" from a AVR. I don't recall where it was I read it, but you should be able to find it. He also created Ladder Logic interpreter to run on the avr.

edit:I found the site where there is "Ladder Logic for PIC and AVR" http://cq.cx/ladder.pl

As carl had mentioned, this doesn't make a AVR a PLC, however it is a different way to write logic.

If I locate the url for the psudo "PLC", I'll post it.

It may have been a PIC instead of a AVR, as I havn't found alot in my brief search. Its been a while since I read about it. It may have been a 8051 or something like that. In either event you should be able to find something on the internet to help.

Last Edited: Sat. Mar 15, 2008 - 10:57 PM
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Rukus wrote:
Somewhere on the internet I read that someone had created a "PLC" from a AVR. I don't recall where it was I read it, but you should be able to find it. He also created Ladder Logic interpreter to run on the avr.

And it may in fact be approaching a PLC.

My only point was that, just because an AVR has 8 optically coupled inputs and 8 isolated relay outputs, and is programmable, that doesn't classify it as a PLC, by anything close to current day standards.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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microcarl wrote:
Rukus wrote:
Somewhere on the internet I read that someone had created a "PLC" from a AVR. I don't recall where it was I read it, but you should be able to find it. He also created Ladder Logic interpreter to run on the avr.

And it may in fact be approaching a PLC.

My only point was that, just because an AVR has 8 optically coupled inputs and 8 isolated relay outputs, and is programmable, that doesn't classify it as a PLC, by anything close to current day standards.

I definatly agree :) I just wanted to pass on the sites that I had seen where this guy created a psudo "PLC", I thought it was kinda cool :)

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Rukus wrote:
microcarl wrote:
Rukus wrote:
Somewhere on the internet I read that someone had created a "PLC" from a AVR. I don't recall where it was I read it, but you should be able to find it. He also created Ladder Logic interpreter to run on the avr.

And it may in fact be approaching a PLC.

My only point was that, just because an AVR has 8 optically coupled inputs and 8 isolated relay outputs, and is programmable, that doesn't classify it as a PLC, by anything close to current day standards.

I definatly agree :) I just wanted to pass on the sites that I had seen where this guy created a psudo "PLC", I thought it was kinda cool :)


I've seen that article too, somewhere.

There is also http://www.parallax.com/Store/Accessories/Other/tabid/167/CategoryID/58/List/0/Level/a/ProductID/290/Default.aspx?SortField=ProductName%2cProductName

Though, really, this controller has it's limitations, as well.

I've often thought about purchasing one, just to see what it's really capable of. But for all but the simplest of applications, it would be quite limited.

Now, if you are going to control your Christmas lights on the outside of your house, your sprinkler system, or use it for a sophisticated home alarm system, the 8 in - 8 out controller, the AVR "PLC " device we've been talking about, and the Parallax device that I've linked to, are all perfect fits for these types of applications - and certanily way more cost effective.

But if you are monitoring say, 30 to 40 remote sensors, driving 30 to 40 outputs, interfacing (handshaking) with upstream & downstream equipment on a production line, etc., these "PLC " approximations described above fall far too short of the standard.

If you want to say that a controller with 8 inputs and 8 outputs passes as a PLC, I suppose in the strictest sense of the definition, it does. But as I said, it doesn't meet the current day definition or classification of what a PLC is.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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My rather simple interpretation of a PLC is that it has Ladder Logic programming software to set the operation(s) of the device. I do recall looking at the controller for a Allen Bradley SLC500/03 , it uses a Intel 8051 type micro controller. I think that the AVR can exceed the functionality of the 8051 chip. The strength of the 500/03 is the supporting software (very expensive) that allows programming of the PLC.
.
So, a PLC could be based on a AVR device, and of course associated external digital/analog devices controlled
by the AVR.
Just my 2 cents

I'll believe corporations
are people when Texas executes one.

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Quote:

...with no flexibility...

Waddya mean?!? As I said, it wraps around my wrist much better than ANY A-B model!

On a bit more serious side, I did control programs and translators and firmware and the like for a PLC manufacturer off and on for quite a few years. Your list, Carl, isn't necessarily bad but there are so many gray areas and overlap and options nowadays that it is really hard to pooh-pooh one implementation over another.

Start with 5. and the "sandardized programming environment". Right away, that is gray. Back when I was you age, there WERE no standards--every manufacturer had a unique language, and the "environments" varied all over the map. I don't think you really mean "environment" anyway--even with one of the standarized IEC languages, the "environment" could be anything from onboard to PDA to custom to PC to VAX.

Now, if one wants to eschew evn the selection of standard IEC forms and have their own flavour, or continue with a proprietary format, I don't think you can flat-out say "that's not a PLC".

Y'all gotta remember that back when I was your age, a PLC brain was a 6809 running at 2MHz with a few k of program space. The next generation moved up to an 80186 at 8MHz. The smallest usable configuration was like 4-in, 4-out though these modular models in practice usually had more cards added.

We have an app board that could easily qualify having, on one board, all the "stuff" that was on the whole line of PLCs I worked on--protected inputs, both digital and analog, and a number of outpus--relays in this case. Commo links and remote display link already onboard, so the only thing missing is the "ladder program" or otherwise Carl's 5.

So, if OP was to use one of our boards as-is, or even one of the more elaborate boards/setups from SparkFun or similar, only 5. is needed with the kernel driver program plus the language translator.

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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http://automatizace.hw.cz/plc-au...

http://www.crouzet.com/millenium...

They use an AVR :-) Anyway, sorry for my bad definition of PLC. I didn't wanna upset ya ;-)

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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tubecut wrote:
My rather simple interpretation of a PLC is that it has Ladder Logic programming software to set the operation(s) of the device. I do recall looking at the controller for a Allen Bradley SLC500/03 , it uses a Intel 8051 type micro controller. I think that the AVR can exceed the functionality of the 8051 chip. The strength of the 500/03 is the supporting software (very expensive) that allows programming of the PLC.
.
So, a PLC could be based on a AVR device, and of course associated external digital/analog devices controlled
by the AVR.
Just my 2 cents

I've been working with the AB SLC503/504/505 for at least the past 15 years. It's my PLC of choice.

While the ladder logic is part of it, it's also the way the program is arranged and executed.

We usually program our AVR controllers in such a way that information generally gets processes in a specific order, depending on the needed requirement.

With a PLC, everything is based on something called a "Scan Time ." Within a given scan time, all of the inputs are gathered and stored in an image table, all of the external communications is received and stored in an image table, all of the internal data (timers, counters, etc.) is gathered and stored in an image table, then the actual program logic is processed based on what is stored in the respective image tables and stored in an output image table and, any data going to external communications is stored in yet another image table. Finally, the scan updates all of the outputs and Communications. There are also other house keeping artifacts that are processed within the current scan.

There are interrupts in higher class PLC that may simply capture an event for the upcoming scan, or it may get processed immediately. But even they have scan time rules to abide by.

So, a PLCs internal operation first gathers all of the information, processes that information and then distributes the results, base on the logic of the program and current internal and external conditions.

If an input became true early on in the execution of the program scan, and later in the same program (based on the ladder logic) scan it is determined that same input has become false, the true condition will not even be seen. It's as if it never occurred. This can be overcome with interrupts and other methods, but it isn't always necessary.

So, part of the differences between a typical AVR controller and a PCL is not only in the hardware, it's in the programming (ladder logic) language, and the way the hardware inputs, internal data, external data, hardware outputs, and communications are acquired, stored, processed and deployed.

I think that to even begin to approaching current day PLC capability, it would take at least the larger Mega class AVR.

And, if you look under the hood of a typical Allen Bradley SLC500 PLC, you'll find that there are dedicated processors for everything. The SLC 503 has a controller for the logical operations, another controller for communications, another controller for communicating with the chassis. In turn, each I/O card employs one or more controller, in addition to a chassis buss interface controller. Now, a typical SLC500 chassis comes in 3, 5, 7, 11, and 18 slot racks. And this is just for a single rack PLC.

Now consider this, to process even one single line of PLC ladder logic within an SLC500/03 requires 2 to 3 milliseconds. That is how much time it takes to just process the scan time. And for each line of ladder program, the scan time lengthens a couple tens of microseconds.

Now, if it takes 10, 15, or even 15 controllers of different types and functionality to create a powerhouse like an SLC500, what can a single AVR - of any class - have to offer in competition.

And to boot, we haven't yet discussed the SLC500/AVR smashing advantages that the newer "ControlLogix " class PLCs bring to the table.

There is a reason why PLCs are set up the way they are, and there is a reason why it takes multiple controllers to get the job done.

An single AVR PLC isn't going to come within a light year of the capability of an industrial grade PCL.

You can call a single AVR controller a PLC, if you want to - but it ain't!!! Plain and simple.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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theusch wrote:
Quote:

...with no flexibility...

Waddya mean?!? As I said, it wraps around my wrist much better than ANY A-B model!

The SLC500 will work just fine when Allen Bradley finally gets around to making it out of flexible PCB material.

theusch wrote:
On a bit more serious side...

Back when I was you age...

Y'all gotta remember that back when I was your age...


You'd better watch it, this could get turned around on you. I'm quite aware of what the MC6809 can do, not to mention the Fairchild F8, Segnetics 8X300i, Rockwell 6502, Zilog Z80, and Motorola MC6800/01/05/11.

Now, as you challenge my age, I challenge you to put a mug of the real you in your avatar and disclose exactly how old you really are. I mean, we all know that you are one of us - a member of the "Old Fart Society ", but you can only get so many miles out of "Back when I was your age... "

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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daqq wrote:
http://automatizace.hw.cz/plc-au...

http://www.crouzet.com/millenium...

They use an AVR :-) Anyway, sorry for my bad definition of PLC. I didn't wanna upset ya ;-)


Well David...

I'm not upset. It's just after spending about 15 years working daily with PLCs, and even longer working with microprocessors & micro-controllers, I have a hard time stepping back and accepting that a 8 input by 8 output embedded controller could pass as a PLC.

I do agree with Lee! The concept of a PLC is quite blurry.

Take the simple statement that goes something like "A computer inputs data, processes that data, and then outputs the results of that processed data ." This is close to a quote used in a lot of entry level computer science books.

Well, in at least two PLC reference books that I have a similar quote "A PLC inputs I/O, processes that I/O, and then outputs the results of that processed to I/O ." is made.

So yes, the concept of a PLC is blurry.

I guess the OP really needs to give his definition of what he thinks a PLC is.

At best, a single AVR might, <<>> approach that of an Allen Bradley MicroLogix 1000 class PLC, or a small Omron "Limited Function " PLC.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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I went and opened up my Modicon micrpPLC 311. It has optically isolated inputs and relay outputs. The processor is an 80188 from Intel. Theoretically, any avr in the 16 bit class could be used. When I programmed Allen-Bradley PLC5 series, they used Motorola 68030 microprocessors. Regardsless of what 'brain' is used the processor is a processor, plain and simple. What really makes a PLC a PLC is the SOFTWARE. The ladder logic is compiled into something the micro can understand. AS carl said earlier, it scans all of it's inputs, and processes what should be done accordingly. Essentially one could write this in 'c' or assembler. It would be difficult, but it could be done. The ladder logic software is indeed expensive because it must take a graphical representation and turn it into machine code.

AS I mentioned earlier, one could set up an AVR with a bootloader that would take the information from it's serial port, self program the flash and then take off. Although it is not a true plc in practice, it does give one the on-the-fly reprogramability.

Jim

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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And one other thing we haven't mentioned yet...

With a PLC, you can connect, get on-line real-time, and see the state & alter of the logic and data, live - real-time - you can force bits, data values, as many other thing.

As far as the personality of the processor, it is the firmware that describes the PLC scanning and I/O handling technique, not necessarily the user software interface.

By far, Allen Bradley's RSLogix 500 is the best PLC software to use - and the easiest.

I have about 6 MicroLogix 1000 PLCs of different flavors and a MicroLogix 1500 here at the house. Owning a legal copy of ROLogix 500 (about $1,400.00US), and for about $300.00 for a MicroLogix 1000, I would not even consider attempting to make (design) a PLC. It would take forever to get something I designed working to the capabilities of a commercially made PLC.

And too, there are the smaller Omron and Mitsubishi PLCs for about $150.00.

And then there is an even smaller "Nano " class PLC offered by AB (and sub-labled by others) that only cost about $50.00US that can be programmed by manual key stroke - and the programming software is free.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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microcarl wrote:

And to boot, we haven't yet discussed the SLC500/AVR smashing advantages that the newer "ControlLogix " class PLCs bring to the table.

One of the large differences in the current generation of ControlLogix PLCs from AB (CLX) vs. the older but still commonly used SLC, that often bites programmers in the behind, is that unlike the SLC's process of scan I/O then scan program, the CLX employs a preemtive systems that scans I/O in the background, making it possible that an I/O have different values on different rungs of logic. This forces you to read I/O into local tags (equivalent of a variable) in the beginning of the program scan if your logic requires read consistency within your program scan.

The point of mentioning this, is to point out that many of the traditional concepts of PLC's logic is changing.I/O scan concept changes together with large use of other programming languages than ladder such as Control System Flowchart(CSF) and Statement List (STL), and C programmable modular systems running common OS like CE, QNX with I/O modules similar to PLC, blurs the line between PLC, EC's (embedded Controlers) and PC's.

So while the mature PLC archictures have many features, hard or impossible to implement in a single AVR, on the low end of the spectrum such "PLC" have already been made and are sold commercially like the "PLC-on-a-chip" products from divelbiss and CUBLOC devices from Comfile Technology (some of which I belive are based on AVR's)

Mikael

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mikaelo wrote:
...implement in a single AVR, on the low end of the spectrum such "PLC" have already been made and are sold commercially like the "PLC-on-a-chip" products from divelbiss and CUBLOC devices from Comfile Technology (some of which I belive are based on AVR's)

Damn! I completely forgot about CUBLOC PLC technology. I looked at them for a while - but only to see what they had to offer over the MicroLogix 1000.

But CUBLOC just re-enforces the idea that designing a PLC from scratch isn't the wise, convenient or prudent path to take. I'm sure that CUBLOC has hundreds of man-hours and many thousands of dollars invested, bringing their product to where it is today.

I think designing a PLC using an AVR for personal use (and especially for a one-off use) is the equivalent of the Newbie claiming that he/she will design and build an ISP programmer or JTAG debugger from scratch - for the learning experience. For the $50.00US, buy the damn thing and get on with the end goal - the project that brought the need for a controller, in the first place.

Unless that person has a great deal of experience with PLCs and understands their role in the industry, it's simply a "Flame, crash & Burn " event.

I just hope the OP has a parachute on, and isn't afraid of height or sudden stops as he/she is falling from high places!

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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First it's nice to be back!

Carl
"Back when I was your age... "
I get this a lot online. Someone will ask a question about some program or equipment that was used in 1982 and I'll respond "Oh yeah, I used one of those 6502, 6800,Z80, 80186, 8"floppy, Atari 800, Cobol, Forth, Pascal,AT modem commands etc and they automatically assume I'm a member of the 'Old Fart Society'

In my day we had to carry our Bytes uphill in the snow both ways with an 8-bit bucket.

I was 11 in 1982. Even worse I look like I'm 20. I still have to remember My ID to buy beer.

I wouldn't call myself AN EE even though I have a piece of paper that tells me I am.
Most of my work is network or programming related I'm just another Noob when I come here.

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Trollicus_Rex wrote:
Carl
"Back when I was your age... "
"...automatically assume I'm a member of the 'Old Fart Society'"

"In my day we had to carry our Bytes uphill in the snow both ways with an 8-bit bucket."


In my youth, when there was a snow storm, it didn't matter if it was 1", or 16" of snow on the ground. If the school bus didn't come, we were expected to walk the 5+ miles to school. Today, if some politician sees 3 snow flakes fall in the span of an hour, school is delayed. If there is an 1/8" of snow on the ground, school gets cancelled.

I know, we've had this discussion before...

The very first microprocessor I programmed was the Fairchild F8, back in about 1975. At the time, there wasn't even an assembler for the thing. We programmed the F8 in binary/hexadecimal, using toggle switches. Once the program was proven, to get a target system running, we hand programmed an EEPROM using a programmer we made - again, using toggle switches.

I don't mind being a member of the "Old Fart Society ". It just irks me to no end, to have someone utter "Back when I was your age... " when I'm probably as old, or even older then that person is. :roll:

Trollicus_Rex wrote:
I was 11 in 1982.

Back in 1982 I was 30 years old. I imagine that back in 1982 Lee was already about 75, and pushing a hand walker... :lol:

So, if Lee is older them me, he can hold the title "Senior Old Fart !" :wink:

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Quote:

So, if Lee is older them me, he can hold the title "Senior Old Fart !"

Back in 1982 I was ... 31 years old. So it isn't even close. Toyed with the Intel 4004 in 1972? 1971?

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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theusch wrote:
Quote:

So, if Lee is older them me, he can hold the title "Senior Old Fart !"

Back in 1982 I was ... 31 years old.

Okay, so you are the "Senior Old Fart ! " You're only a year older then me - or less. :wink:

So don't include me in your "Back when I was your age... " rhetoric. :roll:

In the grand scheme of things, we are after all, the same age. :lol: :P

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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microcarl wrote:

Damn! I completely forgot about CUBLOC PLC technology. I looked at them for a while - but only to see what they had to offer over the MicroLogix 1000.

But CUBLOC just re-enforces the idea that designing a PLC from scratch isn't the wise, convenient or prudent path to take. I'm sure that CUBLOC has hundreds of man-hours and many thousands of dollars invested, bringing their product to where it is today.

I completley agree that if you want a PLC, use a PLC. I you want an uC the use that. Each have their own advantages. The advantage with the CUBLOC device is the level of embedability similar with a uC vs even a small PLC like a MicroLogix brick or a Modicon Momentum, which still need to be placed in a panel.

I would still have a hard time convincing a client to put a uC or a CUBLOC in a panel to move product, as most clients would see $$ in liability if something goes wrong and they chose a less true and tested way of doing things.

After all, once you add $300K of conveyor, what matter does it do if your control system hardware cost 10K? The system developement cost will be well over that either way, so you chose a propriatary system, vs one you can go to Mc&Mc and buy a module for any day of the week to save a few 1000 dollars on up front HW. If you are going to go low budget and need a PLC, I would much rather goto Automation Direct and pick up a $100 PLC than engineering a uC solution. However if I'm creating a product, there is a very different picture.

Mikael

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Quote:
Back in 1982 I was ... 31 years old. So it isn't even close. Toyed with the Intel 4004 in 1972? 1971?

I guess next someone is going to talk about building there own ALU and supporting logic out of discreet components....way back when :-)

I'll believe corporations
are people when Texas executes one.

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tubecut wrote:
Quote:
Back in 1982 I was ... 31 years old. So it isn't even close. Toyed with the Intel 4004 in 1972? 1971?

I guess next someone is going to talk about building there own ALU and supporting logic out of discreet components....way back when :-)

Yes, we played that game too.

What you you think half & full adders were for?

I'm not even sure you can still get a 74xx TTL ALU anymore.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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I do recall many years ago when I lived in Los Angeles, I interviewed for a job at the Observatory on top of Mt. Wilson. They had this HP mini computer that was built with only TTL nand gates. It was all wire wrap, had a tape drive to load in diagnostic programs and you could exercise small portions of say the ALU instruction decoder, test ran in a loop. Couldn't do any thing with out a scope. Didn't get the job anyhow
That is my historical input for this thread. :)

I'll believe corporations
are people when Texas executes one.

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Quote:
I guess next someone is going to talk about building there own ALU and supporting logic out of discreet components....way back when

Or join the retro boys (ossi and barnacle) over on the gloat thread.

I've got 5 years on you Carl, but I don't think I'm the oldest old fart around here. Maybe the fartiest, but not the oldest.

Paid $300 for the first chipset for the 6800. Toggled a lot of switches. Walked uphill both ways in the snow. Barefoot.

Chuck Baird

"I wish I were dumber so I could be more certain about my opinions. It looks fun." -- Scott Adams

http://www.cbaird.org

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zbaird wrote:
I've got 5 years on you Carl, but I don't think I'm the oldest old fart around here. Maybe the fartiest, but not the oldest.

Well, Chuck, the fact that you are my mentor, I'd never dream of calling you "Old Man ," "Fartiest ," or anything else.

I was brought up to respect my elders...

zbaird wrote:
Paid $300 for the first chipset for the 6800. Toggled a lot of switches. Walked uphill both ways in the snow. Barefoot.

I had a "Southwest Technical Products " IMASI, I believe it was called. It was all toggle switches. I built a cassette storage interface for it from an old Byte magazine article. Then in the early 1980's Steve Circeia had an article in Byte for "Multi-bit " error correction. I adapted his work into mine.

I did a lot of "Wire-Wrapping " when I worked at Fairchild. But it was always pre-documented. The error correction project is what cause me to get serious about making PCB prototypes. Documenting a wire-wrapped project really sucks. Then, to just turn around and have to lay out a PCB after all that work! Hell, I decided to just do the projects in PCB and forget about the wire-wrapping.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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About 1971-72-73, when the Intel 4004 came out and our uni "dev" machines were PDP/8s, we had another interesting "minicomputer" to play with: the guidance computer from a Minuteman guided missle. Most details are lost in the haze of time, save for the conical shape, and the green dusty glaze which IIRC was used to neutralize the poisonous coating that helped to protect from sabotage.

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Quote:
Most details are lost in the haze of time, save for the conical shape, and the green dusty glaze which IIRC was used to neutralize the poisonous coating that helped to protect from sabotage.

Ahh, I see...So thats when you starting growing all that fur. :|:

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zbaird wrote:

Or join the retro boys (ossi and barnacle) over on the gloat thread.

I've got 5 years on you Carl, but I don't think I'm the oldest old fart around here. Maybe the fartiest, but not the oldest.

Paid $300 for the first chipset for the 6800. Toggled a lot of switches. Walked uphill both ways in the snow. Barefoot.

Come to the dark side - everybody welcome... The damn thing nearly runs something closely resembling C now. :o

I was only spawned in 1960, so the first micros I played with were the INS8060, and the 8080, 8085, 6800, and 6502 of beloved memory. Best I can claim is 'middle-aged-fart'.

Neil (still got a Sinclair MK14 upstairs - wonder what it's worth?)

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Good God, can we get off the Geritol convention and back to the task at hand?

Ok, To the "Old farts consortium" Great, be glad you made it that long!! :wink: Trade your Metamucil stories in the community forum~~ :shock:

As far as the PLC issue goes, everyone agrees that the OP is off the mark in their desires. But, at the same time inovation in driven by inspiration.

Jim

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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Science of Cambridge Mk14 - that takes me back. My very first 'computer' and portable - I could run it off a PP9 for about 3/4 hour before the battery was flat. I just had to be damn fast with the crappy thumb-busting keypad to get the code in and running (no tape recorder).

Its now gathering dust in a drawer - I hear they are collectors items on e-bay. :D

Regards,

-=mike=-

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Ok, I'll throw my old fart story in the ring.

I got my first taste of 'computers' on an IMSAI8080. The same unit that was in the movie 'WarGames'. I think I still have the unit somewhere next to my commodore64, commodore 64c, Timex Sinclair1000 with 16k memory module, and my original IBMpc with a 10meg hard drive. Yep I kept them all!!

Jim

Forgot to mention the age thing,
For a head of lettuce I am very old, but for a mountain, I have not begun in years.

The wife has an opinion of what kind of mountain I am of course :twisted:

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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Did anyone try to hack it and download HEX file, or map IO pins to AVR pins? :roll:

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Carl: I have a SLC5-3 and looked at the processor board. It uses an Intel 8051 type chip.
I can longer use the AB SLC503, no software. I have since started to use the AutomationDirect products.
I did work for a company that had a inhouse designed board used in a specific application, detention facility controls, that, for marketing purposes was classified as a PLC. I don't recall the certification process or by whom. The PLC(?) was programmed using spread sheet's.

I'll believe corporations
are people when Texas executes one.

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marteenjwiil wrote:
I need help for my project. My project is to create "PLC from AVR microcontroler"...

I'm playing around with my AVR and fellows chips to do the very same thing. If you are still on it, I'd recommend you to start with the Elektor Electronics magazine articles on this topic. Don't miss the March 2006 A Real uC PLC article (based on atmel's 8052):

http://www.elektor.com/magazines...

It also helps quite a lot if you learn how PLC controllers work and how one interacts with them, in the first place. Go google for it and keep patience.

I started building my project with the design mentioned above and later switched to using a AT90USB646 based mini-board instead of 8052 microcontroller (for easy USB programming and communication).

It still has to be noted that to bring a standard "PLC experience" of programming in a ladder, IL or something similar, additional work has to be done on the software side (i.e., PC-side). Since this is somehow out of the scope of my project, I don't really bother with that, as creating a simple PLC on the hardware-level suits my interests just fine for now. Of course, It depends solely on you how big a project you make out of this.

For others... damn! I always get annoyed when somewhere some enthusiast asks for help, advice or directions just to get a bunch of stupid no-tell replies how stupid one supposedly is for trying to do something someone can sell him. Spare your and other people's time, go for a walk instead. Let other people have fun, when they have interest, for Christ's sake... :roll:

Tomo

PS: As far as I understand, the question was not about controlling a factory or whose car goes faster or farther, anyway...

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I think the OP's (class) project is well over after a year ;)

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jayjay1974 wrote:
I think the OP's (class) project is well over after a year ;)

Perhaps, but someone else might also google to this forum with the same or similar question... I know I have... :D

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jgmdesign wrote:
Ok, I'll throw my old fart story in the ring.

I got my first taste of 'computers' on an IMSAI8080. The same unit that was in the movie 'WarGames'. I think I still have the unit somewhere next to my commodore64, commodore 64c, Timex Sinclair1000 with 16k memory module, and my original IBMpc with a 10meg hard drive. Yep I kept them all!!

Jim

Forgot to mention the age thing,
For a head of lettuce I am very old, but for a mountain, I have not begun in years.

The wife has an opinion of what kind of mountain I am of course :twisted:

Siting with an old card on my desk. It is named 65-KK-2- There are used germaniumtransistors on it, ASY26. There are -12V, GND and +12V rails on it. On the card there are monted 17 smal prints, 29x14mm. It contains a NAND-gate. 2K2 for colector, 3x8K2 as inputs, and a 47K down to + to compensate the lekage current. 1/2W were resistors were "standard" those days.

There are place for 2x11 gates like that. In the midel of the board, there are a crosfield.X-direction on upperside, and Y on botum. We drilled holes to connect from Y -> X - Y

Thinking of it. This is, may be, the worlds first Programmabel Arry Logic? 18 I/O. Build in 1965.

My bos learned me howto calculate evry single component on it.

HM

HM