Universal Robots Forum

RobotState error, lag on UI

Hello everyone,

these days I am struggling an error and I do not know how to deal with it:

(pressing CTRL+ALT+F9)

               -ERROR - RobotState messages are queued up: 3 {thread: RobotState - PostMan , loggerClass: com.ur.monitor.RobotState$PostMan}

And every now and then (may be hours or minutes), I get the same message (and sometimes the number also changes)

I am developing a URCap that uses a Daemon to update variables and buttons states on Java side, but this error also appeared with the URCap uninstalled.

On the other hand, I do not know if it is related, but my URCap (an HMI) gets stuck and the robot crashes after some time working nicely (and then I thought that the reason of the ERROR was this, but I am afraid not). In my main program I am waiting for an input signal to continue (this wait for the input signal could be in my case hours) before making some calculations and movements. I am also using in Java side some uiTimers to update the visibility of some buttons/labels and three instances of the daemon (XmlRpcDaemonInterface) to update variables. This seemed to be working very well, so I want to think that the problem is not on this.

Any advice?

Thanks in advance!


I am facing a similar issue where Polyscope freezes while performing a task as its waits for a return value from daemon file. Program or robot does not crashes, it just UI of polyscope get stuck till the function is performed and value is returned back to java class from daemon.

Hi @tal,

Have you found a solution then?

Or I should check that the robot is not waiting for the value from the daemon file?

Hi @GumerCascales

I couldn’t find any solution. I tried running daemon file in the Linux terminal and call the python function through Script programming and then there is no lag in the Polyscope despite waiting for the return value. When I call the same function through java class in the URCap then there is a lag.


Also when you get this error, click on the terminal running the simulator and allow it to catch up. Increasing VirtualMachine’s RAM will decrease the chance of this error occurring.

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