AB CompactLogix firmware 21 issue


I have a 7.7 version of Ignition and I am connected with an AB CompactLogix (firmware 21) through Allen-Bradley Logix5000 Driver. I can read some tags, but some of them not – those tags are in the unknown state.

I attached the log files and you will find below the previous emails regarding the driver for CompactLogix that I am using.

Can you help me to resolve this?

Thank you,

Laura Elena BĂRBOSU
SCADA Programmer
Information Technology Services (ITS)

T. +40 72 617 94 48
Skype: laura.barbosu


I have attached the beta version of the new ControlLogix driver that is currently in development. It’s a stand-alone module, meaning it’s not part of the existing AB drivers module. It will show up in the driver list as “Allen-Bradley Logix5000 Driver”, and requires Ignition 7.6.4 or later. Only direct connections are supported right now so you cannot route via a connection path. Writes work, but are not fully optimized at present so performance when doing bulk writes will not be great right now. The driver should work with both the new v21 firmware as well as older firmware versions.

Please also keep in mind that this is still a beta product and is not intended for a production environment. Please feel free to send any feedback you may have about the functionality of the driver. Hope this helps.

Dave Fogle
Director of Support Services
Inductive Automation
logs.bin.gz (359 KB)

If you’re having problems reading certain UDTs it may be because one or more of the members have their ‘external access’ property set to ‘None’.

Also - make sure you’re using whatever version of the driver got installed with the 7.7 installer and not one of the betas received by email.

Laura -

I have been working through similar issues with v21. As Kevin mentioned, the “external access” setting was a problem for me, among some others that tech support is working on. If I understand correctly, the driver is reading the entire UDT, and it will assign the strictest policy it finds to the entire UDT tag structure, apparently it’s an optimization thing. If you have a single tag set to “none”, the entire UDT will fail. Right now I’m also having issues writing to tags, and am wondering if it is applying a “read only” status to all tags if a single tag is marked as “read only”.

That could be a problem as there are default tags created for an Add On Instruction that are fixed as “read only”. Waiting to hear back from tech support. Also, parameters of an AOI defined as InOut don’t have external access directly, I assume the inherited external access settings are accounted for, but waiting for confirmation from tech support.

Personally I see this as a big problem as Add On Instructions can be locked down. If you are using an AOI that cannot be changed, well you’re pretty much out of luck. I have a proprietary AOI in my application, and while it isn’t locked down I’m hesitant to changing anything in the AOI.

For those who are upgrading an existing application, the OPC path has changed. So if you have defined UDT’s you will have to re-work all of that.

I am starting to evaluate Kepware as an alternative.

Paullys50 - There may not be any good resolution to the external access problem with UDTs, it’s too early to tell, but the problem you’re having writing to some tags is simply a bug on our side we were able to replicate yesterday.

Kevin -

I completely agree that a bug was found, I am glad I was able to produce content for your team to evaluate and I sincerely appreciate the efforts being taken to address my findings. I am sure that things will be sorted out quickly :mrgreen:

Your team and product are excellent! :thumb_left:

For our projects, AOI security could be a potential issue so it’s something I have to consider, naturally anytime you decide to try something new, a backup plan must always be in place!

I was wondering how you are doing with this. We are using the version 21 driver and had to switch to Kepware due to high CPU usage and processor clock sync issues. In about 8 hr may CPU would be > 97% and all memory would be used. In the console log I would have poor tag response and processor clock sync issues.

Switching to KepwareEX solved these issues. It adds licensing cost regarding the rest of the project so I am still working to get this resolved. I was able to call and get a 60 day trial.

We noticed the UDT problem as well we worked around it be mapping tag values in the PLC. I know have other requirements that make this impractical. I do wonder if having UDTs could be related to the issue.