I have a fairly large vi that has about 16 parallel while loops. These read from serial instruments every 5-20 seconds, write data to log files every few minutes, look for button presses, communicate with a FieldPoint unit, etc. I am using LabVIEW 7 running under Windows XP Professional. One particular while loop, which communicates with a serial instrument, has stopped twice after the vi has been running for 3-4 weeks. All the other while loops continue to execute. The loop that stops has a Boolean constant wired to its loop condition so it should not stop until a different loop halts the vi execution. I am not getting any error messages or other indications of failure. The vi and the system in general are not slowing down or showing any other bad symptoms. The only indication that the loop has stopped is that the reading from one instrument is not changing. The instrument itself seems fine, and I am not getting any communication errors. I could program some kind of watchdog to detect when this loop stops, but I know of no way to re-start the while loop without stopping the vi and re-starting it. Any ideas on what might be causing this and how to prevent it? The vi is about 2 MBytes, but I can post it if needed.
Rich
