I've seen this note
which implies that it's not possible to install multiple versions of Unity Pro / Control Expert on the one computer.
However, having come from a Rockwell world, where I have one VM that has RSLogix5000 from version 7.02 all the way up to Studio5000 Logix v32, it seems incredibly painful that I'd need to have a VM for every version of Unity Pro.
Does anyone have a work around to this (similar to that available for Citect?)
Hello @BevanWeiss ,
It's not possible to install multiple versions of Unity Pro / Control Expert on one machine. Application files can be opened in a later version of the software, without having to rebuild or download the application again (application is upward compatible) .
So in general there should be no reason why you use only one version (the latest).
But as some customers insist of standardizing one a specific version, programmers/system integrator's are forced to use this specific version as downward compatibility is not supported by Unity Pro / Control Expert (only upward compatibility).
In general this means that for those programmers working for multiple customers, it's best to have a specific VM, with all the software and specific versions installed for this specific customer. This includes Unity Pro / Control Expert and all other version specific software and DTM's used by the customer, as most of the time it's not only the PLC programming software version you have to dela with. Using customer specific VM's you will have complete control of the installed software at the customers site, without compatibility issues.
The issue with customer specific VMs is that we have several hundred customers... so having a VM per customer is just not practicable.
What we'd really want is similar to the Rockwell RSLogix5000 world, where we can just have one VM with the latest of each major version. Within major versions the file stays the same, so they can always be opened.
I've definitely not seen the behaviour that you mention in regards to the Unity Pro / Control Expert with forward compatibility however. Every time I open an older file, I need to open the .sta version, which then performs an import (not just an open) which leaves the project in an unbuilt state, requiring a re-build, which then marks it as not equal to the online controller.
And that is in addition to the DTM 'updates' which advertise themselves as almost always being breaking updates (i.e. no backwards compatibility available, even for exports).
I might have to have a look into containers I guess.. to see if I can use just a single VM, but 'containerise' each application from the others..
Control Expert (ex Unity Pro) allows to manage several application versions. Opening a STA file keeps the build state of the application with exactly the same signature than the project running in the PLC. the binary created during the build is embedded in the STA file to provide this feature, unlike the XEF or ZEF files which contain only the source.
After opening an STA file you can connect to the PLC and do online modification. Control expert will work with the same library used for the application. For example if you use Control expert V14.1 you can open an STA V6 application. The library used will be the V6, ensuring the compatibility with the running project.To open the program with an older version of Unity Pro you will have to archive it (STA), it will keep the application version, the customer will be able to open it in its old version of Unity Pro.
it may happen, in exceptional rare circumstances , that the status of the application is not build after opening the STA, but even in that case you can connect to the PLC and perform an online build, without stopping the PLC.