Dear ISOGEOCHEM community,

      We have a Delta-Plus that is running Isodat 2.0 (sp 2.63) and is set
up with a dual inlet, continuous flow, and multiport.  We're trying to
measure CO2 gas on the dual inlet for the first time since upgrading to
Isodat 2.0.  I have the right side as the reference and the left as the
sample.  This is a very simple setup that we've used thousands of times in
the past with the old software.  However, I am encountering a problem when
the procedure gets to the pressure/beam adjustment.  I'm wanting each bellow
to adjust to 4000 mV.  I cannot remember from past measurements if Isodat
adjusts the left or right side first.  Either way, what it is doing is not
correct.  It opens valve 25 to accept gas from the reference bellow but
opens the changeover valve in a manner to introduce gas from the SAMPLE
side.  With this arrangement the source obviously does not receive any CO2
and it ends up compressing the sample bellow to 0% at which point I stop the
run.  To me this seems like a script error but I'm typically not modifying
scripts.  I see no where in the method where I have made a mistake, but I
could be wrong.  The bellows have been calibrated, both hardware and
software.  To be more precise, when the pressure adjustment step first
begins the changeover valves are open to take gas from the reference side
but only for a fraction of a second before changing over to accept gas from
the sample side.  All the valves seem to open properly before the pressure
adjustment step.  For example, when performing a peak center it takes the
gas from the reference side as it should. I'm writing to ask if anyone has
noticed a similar bug in the software or if you can offer advice for fixing
the problem?

Thanks in advance,

Joe Lambert
Alabama Stable Isotope Laboratory