Unity Pro XL 4.0 - Quantum PLC - Compatibility and Cables

As part of a comprehensive site survey, I have to mobilise to a remote site (offshore). I have also been asked to take a backup of their PLCs, so I need to take all the software and cables with me, as they have none of their own.

Unfortunately, I have virtually no experience with the Schneider Electric / Modicon platform, so excuse me if my questions sound daft.

I know that they have a redundant Modicon Quantum PLC system with some remote I/O. According to the information I have been provided with:
- the CPUs are redundant Quantum CPUs, P/N: 140CPU67160,
- they were originally programmed with Unity Pro XL V4.0.

Could someone experienced with this platform advise:
- Is Unity software backwards-compatible? If I want to download the program from their PLCs, can I use the newest version, or do I need to find version 4.0?
- What programming cable will be required? As far as I can tell this CPU has got an USB port, I assume that I can use this port to download the program from the PLC?

I will try and find the compatibility chart for you. I'm currently using version 13, so 4 sounds old. Unity was not backwards or even forwards compatible.
From 8 to 13 was easy, as the auto generated .sta files would open and you could still connect to the plc w/ a matching copy. You will probably need the .xef version of the program to open it.
If you only have the .stu, then only v4 will open it.
As far as programming goes, an off the shelf usb to mini will work. You have to go to comms menu, select usb and system.

It should be backward compactible, but after some Unity / CE version blocks librarys of older versions aren't installed by default to PC. (There is naming differences of blocks and upload / opening project is rejected after some time to error on opening.)



You can still install older library versions manually to PC. (There is tool which is installed by default to installation folder)



Unity have 2 different version number.

First is from programming software and another is so called library versions which are used on project for blocks.


(By default for new project newest library is used and library version isn't changed automatically to other even if you program whit newer software versions. Still you can upgrade and dowgrade librarys manually to project, but then you need build all and transfer modified program to PLC.)

If you create totally new project, then libaray and software version are both same. Now 15.1 is newest.


This means that for backward compactibility you need select older firmware version and library if you want later open it also whit older Unity or CE versions.
Still it is good to test whit older version that you can actually open project. From newer installation you don't see which firmares are supported by older versions.


Firmwares which is supported by different versions is only sayed somewhere on manuals or installation help files. (combactibility chart for different firmware versions)



If you make offline modifications for CPU (change CPU version) to different and select too new firmware versions which older Unity versions don't know, you can't open anymore whit older version, even that libary version is same than before CPU firmware change.)


There is two different file types. Stu and Sta.


Stu file can only opened with same version were last save have done.


Then there is sta file (compressed file), which can be opened even on older versions if firmware is knowed by old software and library version is also supported by old software.



I have sometimes programmed as old as 2.3 versions, but for backup I have pretty old Unity 6.0 and XP if I can't connect directly whit newer version. (I haven't had needed it for years thought)




Schneider have allready transferred old Unity version to somewhere hidden place. Good luck to finding 4.0 version which was on use little time.






But it should be possible if you install all old library versions to laptop before connect.



Just make sure that you do transfer from PLC to you computer and don't do download project from PC to PLC.


You don't want mess reduntant system to single CPU state.




Best is if you find *.sta file somewhere saved on customer's PC and it is also show equal state for online connection.






ps. There is backdoor for if only stu file is finded and you have different Unity version.

You can rename stu to sta and then open it to Unity pro.

Unity will decompress file, but it is last builded version (sta is allways builded version).

If stu file was saved with unbuild modifications, then stu renaming and decompressing will forget all these unbuild modifications and Unity open (older) builded project version.


But running PLC have allways builded version of program.