In our current project, we are using Windows 7 64 bit machines. This is the first time we are using Ignition on 64 bit machines and running into lot of issues.
Initially, I installed 64 bit java and 64 bit ignition. With this configuration, Ignition could not establish connection with Kepware OPC server (using OPC-DA method). I uninstalled both Ignition and Java. I installed 32 bit version java and 64 bit version ignition. With this configuration, Ignition could establish connection of Kepware OPC server (DA method not UA). However, I could not launch the designer. It used to pop up error message "Unable to lauch applicatoin".
So, I uninstalled 64 bit Ignition and installed 32 bit version. Now, communication to Kepware OPC from Ignition is working and also the Ignition is working.

Since this project will be moving to commissioning/production phase from next week, I would like to know is the current configuration (32 bit java with 32 bit ignition on 64 bit machine) is a stable configuration or do we need to move back to 32 bit machines? Even if this is stable, what are potential limitations that we will run into in the future?

Is there a reason why you didn't talk OPC-UA to Kepware? Kepware has had OPC-UA capability since 5.3 I think.

I dont think there is a stability issue, just a waste of resources, as Ignition wont be able to use more than 2 GB of memory. How big is this project?

You can't run 32-bit Java and 64-bit Ignition. Use 32/32 or 64/64.

Your COM connection should have worked without issue on 64/64, but Kyle brings up a good point: Why use DA instead of UA?

We have 4 projects where we are using Ignition. At one site, we used 64bit versions of java/ignition and it worked fine. At the second site, we used 64bit versions of both application and it did not work. The project has around 8000 tags and i did not have time to change the path for all the sql tags and hence stayed with OPCDA. At the second site, I am using 32 bit version of both application and it is working now. I am not sure why the 64 bit combination worked at one site and not in the other site.

That is very strange, you shouldn't have any problems installing 64 bit Java/Ignition. What versions of Java were you installing? On the machine that you installed 32 bit Java/Ignition, is there more than one version of Java installed on it?

We found similar problems running OPC DA 32 bit with Ignition 64 and Java 64. In 64 bit environments I suggest if you are going to use OPC DA you are better of using Ignition 32. with Java 32.
OPC DA and DCOM are hard to set up with 64 bit environments and the applications become quite unstable.
Even the OPV quick client becomes unstable, it hangs up the configurator and the ignition server.

Even Microsoft states that Office 32 should be used in 64 bit environments, concurrent applications run better.

I should add that most of the hurdles and pain with 64 bit environments are due to machine configuration.
Once prperly configured most of the stuff we have tested works remarkably well.

The guys at Inductive know their stuff quite well and best of all they take it very serios and provide timely support.

It should be added that if you're using the COM module on a 64-bit machine you also need the 64-bit OPC core components, not the standard 32-bit.

OPC Core Components x64

OPC Core Components x86