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Occasional freeze when reading serial port

I've got a similar problem, and wondered if you had ever resolved yours. I'm a very new, low level user. I've got a controller installed which acts as a server. It sends two pieces of info to our Digital Data Acq system via TCP. One piece is an angle, the other is a 1 or 0 (record command if a "1").


It also reads a count from them, which they update after they have recorded in response to my command.


All works well until the other end goes dead .. which the operators will do daily ... they can turn the Data Acq system on & off at will, but seem to love leaving the Labview application running 24/7.


It SEEMS that if the Digital system isn't up & talking, Labview will lock up .. I get the same ...resetting .....message and have to do a hard reboot.The locking up may take 30 minutes, or may take several hours, but sooner or later will surely happen.


Also running on XP.


Any ideas?



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Message 11 of 14

I did solve my problem and intended to post to the thread.


My solution though came in the form of using the different serial card I mentioned before, a brainbox PX-310, which finally arrived.  The freeze has never reoccurred.  So I know there is an error somewhere between my previous MOXA card and LabVIEW/Windows.  Maybe someday I'll revisit and try and solve it but I won't find the time for a long while.  Our projects doing well - the LabVIEW gui's doing fine.  Thanks all for the help.


Good Luck.


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Message 12 of 14

Had a very similar problem with occasional hangups with serial comm.  My LabVIEW app would randomly hang during serial comm once every 30 - 90 minutes for 5 seconds or so. Then would continue as though nothing had happened.  This was "fixed" by using a USB to serial adapter instead of internal COM port.  No more hangups!  :-)

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Message 13 of 14

Just to clarify my previous post... the usb to serial adapter was a work-around to a problem using LV 5.1.1.  The older code used SERPDRV, a driver used in LV 6.1 and earlier to communicate with the windows serial driver. SERPDRV was just one more layer in the process.  Now, with my code running on LV 2010 or as a stand alone exe, there are no more hangups with serial comm!

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Message 14 of 14