Hi Greg
What you describe could be one of two possibilities:

1) About 2 years ago we had a similar problem with the reference peak disappearing on CO2 where we would lose a sample due to no ref pulse.  This was intermitent, the worst kind.  Sometimes we would do a CO2 only run where the system would stop (luckily)when doing a peak center due to no ref gas.  It got worse with time increasing in frequency.  Finally I did a HUGE amount of manual ON-OFF of the ref capillary in the ConFlo until I got the ref gas disappearing.  Opened the ConFlo interface and found the capillary bent in a V shape rather then sliding into the open split.  The angle of the capillary through the actuator was just a bit to steep.  I bent (slightly... a few mm) the top plate where the capillary goes through to make it more vertical above the open split.  That resolved it immediatly and for good, no more lost samples due to that.

2) We are running Isodat version 1.5 on our Delta XP GasBench II and Isodat 2.0 on our Delta plus without any problems. Both are running with Windows NT4. We have run for months without any computer glitches.  Our second Delta XP is running on Windows XP with Isodat 2.0

However, I destroy all the original Windows installations from the factory because they are flawed (no patches etc.) for both WinNT4 and WinXP.  Also you can install the operating system in your prefered language.  Isodat runs here on the French Windows without so much as a burp (fine food samples).  All our instrument computers are networked allowing us to process and review data at our desks using Excel or a standalone version of Isodat NT followed by Coplen's LIMS database for final storage.

Initial computer installation problems from the factory:
- NT4: Partionned as FAT16 on C with, on certain systems, an NTFS partition on D.  The FAT file system does not handle well large quantities of files in any given directory and is notorious for heavy fragmenting and losing file pieces with time.  Also FAT is not a very secure filing system, NTFS is much more efficient for reducing this to the point of fragmenting once or twice a year with only 15-20% fragmentation.  The deeper the directory the worst it gets for filenames.  Filenames are limited to 256 characters.  This includes all characters from the root directory to where your samples are stored, including spaces in the filename. For example, if you have samples stored where you installed Isodat then your directory structure could be:
d:\Finnigan\ISODAT NT\Global\User\ConFlo II Interface\Results\your sample set 1\sample-xxx-xxx.cfs
There are almost 100 characters just here.  If you create many sample batch sub-directories with long names and the samples have PRE and POST identifiers you can get some pretty long filenames and potentially at some point begin to lose samples.

For an NT4 installation here is what should be considered:
1) Partition disk into 2 or more partions (C and D) with NTFS partitions.  Often 4 GIG partition for C is fine.  D is formatted, again as NTFS, after all is finished on C.
2) It is important to get all of the proper drivers for the hardware.  NT4 is NOT plug and play, so after the initial installation you need to insatll the PNPISA.ini (right click and install) file from the I386 directory on the CD ROM.  This is followed by the Windows NT4 Service Pack 6a.  Connect to the net and go to Windows Update using IE 5 (IE 5 or better is available on Isodat CD)or higher and install all of the Updates (Very very important).
3) Install the operating system and things like an Office suite on C
4) Install Isodat NT followed by the latest Service Pack on D and setup your instrument.

NB: Make sure you know all of your hardware, before you reformat your harddrive. Check your hardware types and versions to get the right drivers from the CD. We are running one machine on a clone home built computer.  Others are running with the Dell machines that came from the factory.

For Windows XP installations on the DeltaXP:
1) Same as above, format C and D as NTFS.  The C can be about 5-6 Gigs with the operating system and other software you may want to use (Office suite).  Same as above, can be in your own language.  D is for documents and Isodat.
2) Windows XP is Plug and play.  It will find pretty much all your hardware on it's own.
3) Install ALL THE SERVICE PACKS for WinXP using the Windows Update on IE 6 or better.  It is critical that Service Pack 2 (or higher) be installed.  It resolves many issues with third party drivers.  For example, if you have only 2 COM ports for peripherals, you can use the BAFO BF-810 USB-COM cable that gives you up to 256 COM ports.  The drivers did not work before SP2 for WinXP.  We are using it on one of our sytems with two GCs and two autosamplers.  It is completely transparent to Isodat.
For the older Deltas, I am still experimenting with a USB-GPIB cable to communicate with the system.  My old GPIB-ISA card does not seem to have a driver for Windows XP.  However, for all the more recent cards (PCI-GPIB) you can find the driver at the National Instrument web site.

PS Get help from your IT Reps if you are not confortable with operating system installations.  Why a C and D partition: If you lose the operating system due to corrupted files or, as happenned to me recently on a 3 year old hardrive, have a dying disk, you may be able to recoup the data before scrapping the harddrive by installing the operating system on D and transfering all data to a safe location.

Gilles

NOTE: Nouvelle adresse de Courrriel / New e-mail address

Gilles St-Jean
Chercheur / Research Scientist
U. d'Ottawa / U. Of Ottawa
Science de la Terre / Earth Sciences
140 Louis Pasteur, Marion-101
Ottawa. Ontario, Canada, K1N 6N5
Tel:(613)562-5800 xt6830(Bureau 1/ Office 1)
                  xt6839(Bureau 2/ Office 2)
                  xt6836(Lab.)
Téléc./Fax: (613)562-5192
Courriel/E-mail: [log in to unmask]
Web: www.isotopes.science.uottawa.ca




> -----Message d'origine-----
> De : Greg Cane [mailto:[log in to unmask]]
> Envoyé : 24 octobre, 2003 17:50
> À : [log in to unmask]
> Objet : [ISOGEOCHEM] Isodat NT 1.5 freezing
>
>
> We've been using Isodat NT 1.50 over the last 2 months with
> no problems
> whatsoever, analysing N2O samples for nitrogen and oxygen
> isotopes in a
> continuous flow environment. However, I have begun experiencing a
> recurring problem with Isodat whereby it seemingly freezes at
> random at
> the start of a sample. In our method script, we do a peak
> center at the
> start of each sample and an error occurs displaying "Peak center could
> not be found". At this point, the program freezes and my
> analytical run
> is halted. Like I said, it's random and I've just begun having this
> problem. I'm able to get the software and my analytical run up and
> running again by rebooting the PC. Might this problem be associated to
> an accumulation of .cf files in the results folder? Any
> thoughts/suggestions?
>
> Much appreciated,
>
> Greg Cane
> Princeton University