Hello everyone,
A short while ago, I posted a question concerning issuing an XWin-NMR
command from outside of the XWin-NMR program, in particular from our UPS
system. I received a number of responses, and I wish to thank you all.
Because about half of the responses wanted to learn what I found out, I
am posting this summary.
Firstly, no one provided a way to issue an XWin-NMR command (such as
HALT) from outside of the program. It would seem, therefore, that this
is impossible.
One person was concerned about how the PWRDWN proceedure was
implemented. He suggested that it would be better if the amps were
powered down, but the console should continue to operate so that the
fans could dissipate any heat. I agree that this would be
preferable. It may be possible to modify the PWRDWN.BAT to include such
functionality, but I do not know how to do so.
I did receive numerous messages that suggested ways to minimize the
amount of lost data when the system was shut-down as a result of a power
failure. These solutions loosely fall into two catagories:
1. modify the pulse program to include a write statement, and
2. make use of an AU program such as "interleave".
Modifying a typical 1D-NMR pulse program to include a write statement
(2D experiments already have such a statement) is pretty
straightforward. However, because there are so many different 1D pulse
programs (eg. zg30, zgpg, dept135, etc.), each one would need to be
similarly modified.
The "interleave" AU program makes use of the TD0 parameter. When the
interleave AU is executed, then the parameters NS and TDO are read from
the current dataset, and NS scans are acquired, TD0 times, giving a
total number of scans equal to NS*TD0. So, if NS = 256, and TD0 = 10,
then the total number of scans will be 2560. If a power failure occurs
during this experiment, then the maximum number of scans lost will be 255.
Because we operate our centre as a multi-user, hands-on facility, and
since we are often making use of an autosampler, and ICON-NMR, I have
decided to write my own AU program and have incorporated it into our
standard 1D-NMR datasets as the AUNM parameter. The intent was that
the program would work transparently: if a user submits an experiment
with 5000 scans, then the program will execute 19 loops of 256 scans
each, and then a 20th loop of 136 scans. The data is written after each
loop.
Thanks again to everyone who responded.
If anyone would like a copy of my AU program, please let me know.
Also, if anyone knows how to modify the PWRDWN.bat file to have the amps
power-down for a few minutes before the rest of the console, that too
would be appreciated.
Cheers,
Bob.
-- Dr. Bob Berno NMR Operator, ARMRC Department of Chemistry Dalhousie University Halifax, NS B3H 4J3 Website: www.armrc.chemistry.dal.ca Phone: (902) 494-6034 Fax: (902) 494-1310
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