Varian UNITY INOVA NMR, Установка оборудования, Страница: 19 / 65

Chapter 2. Wideband NMR Module
18
UNITY
INOVA Solids Hardware Installation 01-999044-00 C0501
c. Double click on the
loadpatch
icon. Read the instructions associated with
the installation. The installation may take several minutes.
An alternative to using File Manager is to use a Shell Tool. Open a Shell Tool,
change to the
/cdrom
directory and enter
./loadpath
.
7. Configure VNMR (CONFIG) to have the maximum spectral width of 5 MHz.
8. Go to the next section to test the Wideband NMR Module.
2.2 Testing the Wideband NMR Module
For the following tests disconnect the probe from the preamplifier and terminate the port on
the preamplifier with a 50 ohm load. Set
tpwr=0.0
and
pw=0
to avoid applying power to
the load.
500 kHz ADC Test
Recall an
s2pul
parameter set. Enter
nt=1 sw=100 np=8k tpwr=0 pw=0 go
.
If the run terminates with an error “
np not equal to number of points
” check
the cable connections that were just made.
Wideband Module Test
Enter
sw=5e6 np=8k go
. If no errors occur, enter
wft
and inspect the spectrum.
The noise pattern should be approximately symmetric and contain no spurious signals. The
noise level at ±2.5e6 Hz should be about 1/3 that at the center.
If errors occur check the cable connections. If no errors or spurious signals occur the
installation is complete.
Data Transfer Test
The wideband module makes it possible to acquire data faster than the computer can store
it. A fifo underflow will then occur. VNMR 5.3 and later software warns when this might
happen and suggests a
d0
or
d1
value that will avoid the problem.
For a 1D acquisition with
bs='n'
, data transfer from the Wideline NMR Module to the
Sun occurs at the end of the run. Acquisition of data with the maximum
np
(256k for the
beta boards) and
d1=0
is possible.
For UNITY INOVA when
bs>0
, during arrayed or 2D operation or during real-time display of
acquisition, the data-transfer between the Wideband NMR Module and the Sun takes place
during the
d1
delay period. The minimum value of
d1
(required to complete the transfer)
is determined by the number of points,
np
, and the speed of data-transfer, which depends
on the amount of memory on the Wideline NMR Module. Incomplete transfer causes a fifo-
underflow error. The table below shows typical values of
d1
versus
np
for the current beta
boards (1 MB of memory). Released boards will have 2 MB. They will run with faster data-
transfer rates and trap for most fifo-underflow conditions.
np bs d1(s)
>64k >0, acqi, 2D, or array operation unreliable
64k >0, acqi, 2D, or array 0.4
32k >0, acqi, 2D, or array 0.2