FX3U clone problem uploading a code with gx works2

[eagl1]

I'm starting learning ladder programming.

I bought the FX3U kit + coolmay HMI from aliexpress.

I'm doing basic testing and uploading codes.

I found this example on YouTube about RAMP function. According to the layout:

The code in this video:
https://www.youtube.com/watch?v=9-vyN9eSGFk


I'm not sure what is RAMP, is it sending analog voltage on DA0 or DA1 ?

So I did the example on gx works2 and compiled the code and did the debugging simulation and it worked, but when I wanted to upload the code to the PLC I got this message:

What is the problem ?

Another request, is there any series of tutorials or a document about FX3U instructions ?

 

[parky]

It is almost certainly the capacity of the clone board is less than the total program steps in the file you are trying to download.
These clones are not true FX PLC's there are some differences for example some functions are not availlable & memory is often less. also on many you cannot download the PLC Parameters as they are fixed. I noticed the error says memory cassete there will be no memory cassete only ram so make sure you select download to program memory (Ram) not cassete, also although you cannot write to the PLC Parameters set the memory size in PLC Parameters to 8K as these units very often do not support larhger memory.

 

[eagl1]

It is almost certainly the capacity of the clone board is less than the total program steps in the file you are trying to download.

But the program is a simple one, if you check the video it's an example about the RAMP function.

These clones are not true FX PLC's there are some differences for example some functions are not available & memory is often less.

Yep, the clone contains STM32F103 microcontroller, I know the one on a true FX3U should be a much faster with more memory microcontroller.

and also I've been told here on this forum on a previous post that there are certain functions aren't available for the clone. I think the RAMP function is one of them and that's why the program didn't upload.

also on many you cannot download the PLC Parameters as they are fixed.

Yep, like the baud rate for the communication between the PC and the PLC during programming phase.

I think I have to find a file that is specific for the clone.

 

[eagl1]

I found this page, it's mentioning the specs of this clone.

https://pdacontrolen.com/revision-hardware-plc-lollette-fx3u-14mr-le3u-fx3u-fx3uc-part-1/

one interesting information about the speed of the PLC:

Speed: 3 kHz

What does that mean exactly ? Is it the speed of the microcontroller actual speed of execution ? but the microcontroller itself runs @72MHz, how did it came down to only 3kHz ? That's a very slow speed.

 

[parky]

I suspect it refers to the high speed inputs, on a true FX these are 5kz.
When you try to download what selection do you have for the target I do not have a PLC availlable but from memory I seem to remember you can select tha target memory i.e. RAM/cassete etc. I cannot remember exactly as GXW2 will not show you the target until it checks on-line with PLC (does not show options on simulator) so it would be worth it to check the target memory you are writing to.

 

[Blenderhedd]

You are exceeding the parameter settings for something. IDK if this has to do with the RAMP or not, but this same error pops up when you try to write comments to the PLC without having set aside sufficient storage space.
And, yes, it DOES say "memory cassette" whether a cassette is present or not. The number on the bottom may denote something useful, but the text itself is a generic parameter error.

 

[parky]

Yes, the default I think will select download of symbols, this would probably not have enough space to store both the code & symbolic information. there are other things to be aware of, as from firmware version C on real FX's certain extra space was allocated for compiler generated symbolic addresses, these are in the higher range not supported on older processors & probably not on the clones. there was another post recently on this, it would compile & download but would not work (internal output bits not turning on), The answer to this was to use absolute addresses with symbols & not use symbolic only addressing.
There can also be problems with creating function blocks on clones as these use symbolic only address space to pass data to calling function blocks.
Although you can change the device automatic assignment to a lower range never tried it on a clone.
As a side note: you have a relay output board type so there is one function (PLSY) that will not work as it is a high speed pulse train to an output that can only work on a transistor output board.

 

[Ronnie Sullivan]

£8 for a PLC and it doesn't have a full instruction set. Ripoff

 

[parky]

They are not bad for the price, a friend of mine has two running various things in his house, I got one just for curiosity really, quite impressed, I think it is more like an FX2N but still limited, you cannot change the PLC parameters, or the baud rate, the analogues are like the old style i.e. have to use the RD3A function rather than the TO/FROM functions seems to do most functions including float maths. One problem in using GXWorks2 is the symbolic only variables, seems these may be outside the clone actual variable address space but providing you use global symbolic with actual address space seems fine.

 

[eagl1]

They are not bad for the price

Yep, I'm actually new to knowing about PLC clones, I thought that would be for microcontroller boards. Almost everything in the world has its clone

Then I thought, why I bought this thing in the first place when it's a clone and doesn't have the same processor as in the original FX3U. And of course the answer is the price.

Then I understood the beauty of this clone, the design let me to program it in Gx works2 the MITSUBISHI official IDE, so this clone maybe get me the functionality and the experience of using and programming an original FX3U.

I think it is more like an FX2N but still limited, you cannot change the PLC parameters, or the baud rate

Yep, I noticed that I only have 38.4kbps, but it doesn't matter.

But what you mean that I can't change the parameters, which parameters ?

the analogues are like the old style i.e. have to use the RD3A function rather than the TO/FROM functions

seems to do most functions including float maths.

Do you mean "TO/FROM" similar to RAMP parameters ? So I can't use a function that has "TO/FROM" parameters ?

One problem in using GXWorks2 is the symbolic only variables, seems these may be outside the clone actual variable address space but providing you use global symbolic with actual address space seems fine.

What does than mean ? Can you provide with an example ?

 

[parky]

On a true FX there is a PLC Parameter file, top of the list in the Project navigation, there you can set the PLC Memory size, what devices are retentive i.e. hold their data on power down & many other things, on most of the clones you can change them in your project but cannot download them to the PLC.

The RAMP function may work as it is just ramping up a value in a word, that word would then have to be transferred to an analogue output using the WR3A instruction to move it to the in-built analogue output for example RAMP[S1,S2,D,10] would send a ramp value to "D" (perhaps a D register like D100) then call the WR3A function WR3A[0, 0,D100] (chanel no., Analogue no., value]
Yes to comply with the newer IEC ccode rather than use absolute addresses i.e. M20, D45 etc. you can give it just a symbolic name like My_Variable, when you compile the program it automatically assigns a real register or bit to it. the problem is these are in a range that most clones cannot access as they do not exist, i.e. M9000 or D9000 (generally only available in later versions of real FX units.) The same goes if you have an HMI connected to the PLC the HMI can only address registers like M0-M999 or D0 -D511. as these symbolic only addresses have no pre-defined actual address the HMI cannot read or write to them. The AB range of control logix processors do not use actual addresses but symbolic so they can, as Mitsubishi have made their platforms backward compatible they have kept the real addressing system but believe on the later processors have a symbol table stored in the PLC so HMI's can read/write to symbolic addresses.
In the pic attached, you can see that the first variable has an actual address the second does not, this is assigned automatically, but would be in the range of the automatic assigned variables of the table above (these are extended variables probably not availlable in the clone).

 

[eagl1]

I found the company that developed these clones.

I found some basic information about the model, it's labeled as LE3U which means FX3U.

And the only document provided is this one:
https://www.xueplc.com/wp-content/uploads/2021/01/LE3U-Manual.pdf

Not much of information about the instructions.

I even don't have any experience in ladder programming, it's almost like assembly language.

What should I do ? How to start developing a good project ?

The design I'm thinking about is like these projects, nothing difficult just for projects showroom:

Choose some inputs/outputs with the HMI. That should be a good project for diploma degree.

 

[goghie]

@eag1 That picture makes me scared. I try to imagine situation where I want to buy spares in 5 years, or inspection ask me for relevant certificates, and not to mention Intellectual Property. Initial cost of PLC equipment in industry is usually just fraction of total cost and, in my opinion, it is not place to be cheap.

 

[eagl1]

I tried to understand your point of view, what you mean exactly ?

Do you mean that this project would cost me a lot ? or I can't build something on a simple budget ?

Maybe you didn't understand me, I'm not working in industry, I'm working in a college and I supervise diploma projects. So the projects we do aren't for real time duty system. Just for graduation projects and learning purposes.

 

[goghie]

For learning purposes it is somehow ok, but you should keep in mind that even original FX3U capabilities are quite obsolete now. FX3U is over two decades old PLC.
As for graduation project, I can't comprehend how is it allowed by university to use clones. I know that Mitsubishi is donating it's equipment to universities, so it would be much better option.
Universities should learn engineers how to think, and how to put priority on safety and intellectual property.
You even don't need real equipment for learning, as GxWorks has excellent simulator.