FX2N-20MT PLC (clone of Mitsubishi)

lwmar

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Hi everyone,


I am new here and this is my first post. I've just received my new PLC by post. It is a FX2N-20MT, a chinese clone of a Mitsubishi. One of the things I am wondering is if it is possible to connect it to the PC using the non-removable and non-interchangeable RS-232 that comes with it to have a scada system running. As far as I can see in the manuals I downloaded from Mitsubishi the original PLC comes with a port to connect different optional modules, but the clone I have does not have that port or any other rather than the RS-232. I think probably someone has some experience with this clone and can tell me something useful as I am not an experienced user and this PLC I bought comes with no information at all. I only coded in ladder using some basic functions on a Siemens S7-200 two years ago.


Many thanks
Regards


Marcelo
 
It does depend on the clone, the very cheap ones, i.e. the ones that are not enclosed but on a simple klipon type support have limited functionality, The most noticeable differences are:
1. The 232 port will only communicate at 19,200 baud, the PLC Parameters cannot be changed, if using GXDeveloper or any other IDE then you have to set the PL:C Parameter memory size to 8kb (although you cannot read or write the PLC Parameters you cannot download to the PLC unless the above settings are made).
2. Most functions of the FX2N do work, however, there are a few that do not, one thing about the ones with on-board analogues is you have to use RD3A & WR3A rather than the TO/FROM instructions, I have not tried the more expensive clones so cannot comment but I would not be surprised if they are not exactly clones. As for expansion cards again I cannot tell you if they work or not.
One thing that you may be able to do is add an ethernet to 232 converter like the ATOP, I once used this on a couple of FX2N's & that worked reasonably well, but that was with Kepserver OPC, that has Ethernet encapsulation.
One other point, These are ok for learning or home projects but to use them in an industrial environment is not recommended, there are issues, the units are not approved by any legislation, probably not CE approved, if you are supplying a customer you would almost certainly be prosecuted & liable for damages should something go wrong.

It will depend on the Scada, providing it uses the native Melsec protocol it will communicate, the only difference is the 232 port is a 422 port on the FX2N but the protocol is the same.
The add on modules for the FX2N (now obsolete) will communicate in a number of modes i.e. ASCII, MC Protocol & Melsec, however, no idea if these will work on a clone.
 
Last edited:
Hi everyone,


I am new here and this is my first post. I've just received my new PLC by post. It is a FX2N-20MT, a chinese clone of a Mitsubishi. One of the things I am wondering is if it is possible to connect it to the PC using the non-removable and non-interchangeable RS-232 that comes with it to have a scada system running. As far as I can see in the manuals I downloaded from Mitsubishi the original PLC comes with a port to connect different optional modules, but the clone I have does not have that port or any other rather than the RS-232. I think probably someone has some experience with this clone and can tell me something useful as I am not an experienced user and this PLC I bought comes with no information at all. I only coded in ladder using some basic functions on a Siemens S7-200 two years ago.


Many thanks
Regards


Marcelo

What a strange post, why on earth did you decide to buy a clone then ask questions about it's suitability and capability ?

There are many better options out there if you wanted to buy a PLC for an application or to learn on than buying cheap Chinese clones.
 
I paid around 22 U$d for this one and it comes with no enclosure so it is probably one of the cheap ones. parky: Do you know all that just because of your experience with them or is it any place where I can read more about this clones? Do you remember if the PID works? Don't worry I am not going to use it at any industry, just for learning. Now I need to make a cable to connect it to my PC to start the coding, I am wondering if any serial to USB converter is ok, as I read somewhere thay it may not be fine. My biggest concern is to know if I can burn up something or if it will just not work if I connect it in a wrong way. Where you say "the only difference is the 232 port is a 422 port on the FX2N but the protocol is the same": does it mean I need to get a RS422 to RS232 converter to connect it to the PC for coding?
tragically1969: I read somewhere on the internet that this units are clones, that is why I bought it. However next time I will do more reading before buying.

Many thanks
Best Regards

Marcelo
 
One of my old apprentices purchased one, I was quite impressed for the price, the PID instruction I don't think will work, but it is simple to do a PID I assume the one you have has the analogues built in. these are 0-10v only I believe. I did a simple PI control on one & to test it I used a PSU & a auto bulb to generate the heat source, bonded a PT100 plus 0-10v converter to the bulb & it worked a treat.
The cable you need is a USB to 232 converter, the UGREEN ones from Amazon work well, it plugs strait in. just remember to set the baud rate to 19200 & the PLC Parameter memory to 8K.
You will probably find it already has some simple code to show you how to use the analogs & simple input/output logic.
I did one for simple PID control I will see if I can dig it out but it was in GXWorks2 will need to convert it to GX Developer & post it.
Come to think about it the one my apprentice had was supposed to be an FX3U equivalent, but providing the version is recent it should have all the functions I have used.
 
I congratulate those who manage to set up an efficient system spending very little.

Good starting point to learn, I liked Mitsubishi programming and never used the PID instruction, I made my own algorithms.

Does this clone support floating point calculation?
 
The FX2N does support the PID instruction but not sure if the clone will, but it may be worth a try, the PID uses a lot of "D" registers for the PID process so you will have to get your head round how it works. I used it many years ago & it worked well once I got my head round it, One problem with the FX2N is it's use of Floats, the Fx3 has better functions for example I believe the FX2 cannot use fixed float constants so you have to convert them to floats and store them in a double register first.
 
Ladder description request, analog inputs

Thanks for the PDF. Could you please write a description of what it does? Mitsubishi's ladder is still difficult to understand for me. I used Siemens and it was easier for me. Exactly what inputs and outputs numbers are analog on the FX2N-20MT? Or that can be selected/changed somewhere? I read somewhere that this PLC comes with only 2 analog inputs, is that right?


Many thanks
Regards


Marcelo
 
Hello Marcelo. In this forum we try to help as much as possible. But it is helpful trying to do a bit of effort, like studying the documentation. I have experience with Mitsubishi, but had never used he command RD3A. Yet it took me a few minutes to understand parky's program. You will be able to solve many issues much faster by trying a little bit. Please see the below explanation which I hope will clarify your inquiry. Good luck.

20210516_Melsec_FX.jpg
 
Thanks Alfredo,



The problem I have is that I cannot find the exact model of the PLC I have in the Mitsubishi documentation (FX2N-20MT) so I don't know where to look. Maybe because it is a chinese one. I am also confused because in the image you posted says "FX3G/FX3U/FX3UC..." in the first line of the title on the left top corner. Furthermore I don't know which ones are the analog inputs, and their specifications (as voltage range, etc.). Things mentioned in the image as "analog input channel number", "card address" and "analog address" means nothing to me really. I cannot see anywhere X0 to X13 which is how my inputs are called in the board.
 
OK, I thought you were asking about the ladder that parky sent, which is what I tried to explain.
You are providing information little by little. Now you say "I cannot see anywhere X0 to X13 which is how my inputs are called in the board". You mean you cannot see in the sample program sent by parky, I am guessing...
Not sure for a Mitsubishi clone, but in Mitsubishi, "X" means discrete inputs. So it seems your board can only read discrete inputs.
On post number 10 you ask "I read somewhere that this PLC comes with only 2 analog inputs, is that right?" Well, if you can only see X0 to X13, then I think your PLC does not have analogue inputs. Can you post a picture of this card? I can't help you as I do not know what is it you have.
 
There are many versions of the clones, some have analogue other don't.
Did you but it via Amazon, if you look on their site. If it has analogues and it is a type without the same style case i.e. probably just a board mounted on a plastic base then if it has analogues these are on the right hand side if it is like the board I had a play with, the commands are the same for FX2N & FX3U, but the FX3U has more memory and some extra commands.
Here is the pic of the FX3U card, As I stated there are hundreds of them out there & come in many forms perhaps you could post a pic of yours.
Often the X & Y inputs/outputs & the A in & out are printed on the main board but they are hard to see.
I did manage to google the board my apprentice had and selected images there happened to be an image of how to connect the analogues.

FX3U.jpg
 
Here is a picture of the PLC I have, I bought it on Aliexpress. Now I've found out that in Amazon it says it does not come with analog inputs. This is the problem with most chinese stuff: documentation is almost non-existent and contradictory, bad translations, no support, etc.

How I can make a cheap analog to digital converter which produces digital data that is easy to work with while programming this PLC? I prefer to make it from components rather than buying modules as locally I can buy the components but modules are much more expensive and difficult to find.
K2bW3nT.jpg


PLC FX2N-20MT.jpg
 

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