PR1 Internal control handle invalid on View Messages

Has anyone else received an “Internal control engine handle invalid.” Code -403 error when trying to view the control engine messages?

I have a PR1 that is consistently doing this, and then the strategy restarts. Does it from PAC Control and PAC Terminal.

Logs that may be relevant:











[2021-06-07 16:57:38] Set HOME to /home/pac22/

Opto 22 Control Engine

Copyright (c) 2001-2020 Opto 22

Version: R10.3b

Build Date: 05/13/2020

Build Time: 18:32:43

This product includes software developed by the OpenSSL Project

for use in the OpenSSL Toolkit (

[Creating User Threads]:


[2021-06-07 16:57:39] [Running]: Press <Ctrl><C> to quit

[2021-06-07 16:57:39] [H0]+1:Total=1

[2021-06-07 17:03:58] [H0]+1:Total=2

[2021-06-07 17:03:58] Error: Signal 11:

Ok, I have good news and bad news on this one for you @philip
The good news is it’s a very fresh bug, not many cases of it, but the developer has seen it and feels confident its been fixed.
The bad news is because its so new the fix did not make it into the 3.2.1 firmware update due out later today. (Mostly an Ignition version update, but they did address ‘your’ bug in it: RIO Save to flash / custom data access area not persisting with KB89662 showing it was fixed in 3.2.0, but I see it fix in the readme for 3.2.1 - sooo, uh…)

If your strategy can be tickled to cause the bug at will it would be helpful for our guys to use it in testing.
If so, please reach out to our support team.

This unit had old firmware on it, so I took the opportunity to update it to 3.2.0. Downloaded the strategy and the issue doesn’t happen.

My thinking is that the area where the log is stored was somehow corrupted and a reflash fixed it. Not sure though.

I’m told it is more a queue error issue, not a memory or log file issue. If wrong or bad data get pushed into the queue, that’s when the bug is activated and the control engine restarts as a result.

Okay, interesting, I did just add more IO modules to this unit, powered it up and then downloaded the strategy before this started happening.