Dear Chris:
I found nothing in the self-help pages that helped with this problem. The
reason for the long wait before re-contacting you is that I spent six weeks
on vacation and when I returned, my computer died. When I got it running
again, the first thing I did was run the program to see if it would fail -
hoping that the problem was my computer all along. It wasn't the computer.
The program ran nicely for several hours, then simply stopped in the usual
fashion without error messages. At that point, the only thing one can do is
terminate the program.
HELP!
S. F. Bush
----- Original Message -----
From:
To: Bush, Stewart
Sent: Wednesday, April 18, 2001 1:20 PM
Subject: Re: (Reference#2330-LBH227) Intermittent hangs of program during
execution
>
> Note: Your reference number is included in the subject field of this
> message. It is very important not to remove or modify this reference
> number, or your message may be returned to you.
>
>
> Stewart --
>
> Thank you for contacting National Instruments. I apologize for the
> delay.
>
> The following webpages address issues similar to yours:
>
> http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/594586
> 84cf7861cc862565410061db3b?OpenDocument
>
> http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/8d5bed
> 8d77b96c49852563a9004585bd?OpenDocument
>
> http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/348367
> 225079f32e86256930006fd480?OpenDocument
>
>
> This webpage contains a link to another webpage that talks about
> performing
> a loopback test:
> http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/e22da8
> 5e97818de78625678c0069bfc9?OpenDocument
>
> This test will help determine if there is a problem with the serial
> driver,
> port, etc.
>
> If the suggestions on these webpages do not help solve your problem
> please
> let us know.
>
>
> Regards.
>
> Christopher Mitchell
> National Instruments
> http://www.ni.com/support
>
> ------------------------------------------------------------------------
> ------
>
> Problem Description :
> We control a stepper motot of a monochromator using the serial ports to
> communicate with the ISA control modules. We step the motor, control
> high
> voltage power to the PMT detector, and acquire intenstiy data from the
> PMT.
> In addition we have an NI-LabPC+ interface card (non Plug-and-play) with
> which we control a constant temperature bath and collect temperature
> information.
>
> All of the control and data acquistion is carried out simultaneously.
> Typically we will establish the temperature of the sample, collect up to
> 100 signal-averaged spectra, store the spectral data, alter the
> temperature, and repeat the collection of spectral data. The time
> required
> for a complete thermal profile requires the above process to be repeated
> over and over - usually three to four days of continuous operation.
> We are trying to use LabView to automate this process. While the
> operation
> proceeds smoothly using our LabView programs(some of the basic VI's were
> created by ISA), at some point, in the execution the program hangs with
> no
> error messages.
>
> In some instances of program failure, we have had an error light(motor
> busy) turn red. Using this as a starting point, we have backtracked to
> try
> and find the cause of the problem. We believe that the problem
> originates
> in the lowest level Serial Port Read VI. It is our belief that the
> Serial
> Port Read VI is missing or misreading data perhaps due to timing
> problems.
> This only occurs rarely, but when it does occur the system stops and
> appears to wait for data, which it never gets. To try and correct this
> problem, the Serial Port Read.VI was replaced with the Serial Read
> WithTimeout.VI. This served to exacerbate the problem. The program would
> not excute at all. It seems that the Serial Read WithTimeout.VI is
> designed to work with VISA applications only (plug-and-play), and our
> LabPC+ card is non plug-and-play.
>
> We are desperate for help! I can forward the file/program to you if it will help. I have already tried all suggestions given so far but nothing you have suggested has helped. This is an important
> research problem in which we have invested a great deal of time trying
> to
> make LabView software work for us. At this time the unreliable software
> is
> the main obstacle to this project being completed.
> NI Software :
> LabVIEW
> Version :
> 6.i
> OS :
> Windows 98
> NI Hardware :
> LabPC+
> Drivers :
> N/A
> Other Hardware/Instruments :
> 3Com Network adapter, Soundblaster, USB ports We communicate with other
> hardware through the serial ports: includes ISA SpectrAcq2, ISA high
> voltage PMT supply, ISA retro control monochromator box.
> CPU :
> Pentium
> RAM :
> 128
> Vendor :
> MIcrocomputer Center (MCC)
> Customer Information :
> Stewart Bush
> UNC Charlotte
> US
> sfbush@email.uncc.edu
> Ph: (
> 704
> )
> 687-4435
