Posted 17 Nov 2016 I was practicing some concepts on concurrency in periodic tasks where I handle such using SSV instruction to inhibit tasks, as suggested by Logix5000 Programmer Manual and after I downloaded the program through ethernet cable to the PLC (Compact Logix L32E) it became impossible to communicate to it, showing 1789 Virtual Chassis in the Who Active Window isntead of the PLC I'm using. I tried to reconfigure it using RSLinx and serial cable but I had no success, the only solution was reset it by removing its batery. I was wondering what could have caused the problem. Concurrency.ACD Share this post Link to post Share on other sites
Posted 17 Nov 2016 Haven't looked at your program yet, but check your task scan rates. I brought the scan rate of a periodic task way down when I was playing around with a bench processor and it didnt allow time for communications. It was easily solved by putting the processor in program mode. Share this post Link to post Share on other sites
Posted 17 Nov 2016 both your tasks are 20ms rates and the event is called from those tasks so I dont see where you could be having the issue I described. Is it possible that you changed the communication configuration when you downloaded? Should have been pretty easy to autosync the serial though. Did you try setting the serial configuration in RSLinx up again when you lost comms or did you just use the configuration that you already had? Share this post Link to post Share on other sites