Bruker Fourier 300, Quick Start Installation Manual

Page: 17 / 22

17 Z33048_00_01
Appendix
Appendix A
A.1 Main Differences Between Fourier and AVANCE
The main differences between the Fourier and AVANCE are that with the Fourier:
•
The lock works at 1 kHz instead of 6 kHz, which means that sidebands are closer
together. Also, the lock parameters have different units for BSMS values.
• The shims and the BSMS field are not automatically set after power up. You will
need to load a valid shim set using “
rsh
” to set the shim currents, and switch on the
lock in the BSMS panel to set the current BSMS DAC value.
• The shim values range from -32768 to 32768. When converting from an AVANCE
shim file, you will need to halve the values to get a good starting point.
• There is no PID self tune for the lock, VTU and spin parameters. Since the Fourier is
only sold with one probe, the defaults, when operated at 4 bar, are usually good
enough for all experiments. Refer to the service manual for defaults.
• There is no PICS. You will need to copy “probe.ph” to the corresponding directory.
• The “
wobb
” command doesn't work from within TopSpin. There is a wobble function
using a stand-alone program. Refer to the service manual for details.
• There is a different pulse programmer language. Refer to the service manual for
details.
• The Digitizer Type must be set to “DRMS”.
• The Aq.mod must be set to qsim.
• The Fn_Mod must be set to TPPI or QF.
• The BC-Mod must always be set to OFF.
• The GPNAM must always be RECT.1
.
Table 1.1. Typical BSMS Values for the Fourier
P: 0.1 to 0.8 depending on solvent. Higher values mean more
proportional
gain.
I: 0.1 to 0.8 depending on solvent. Higher values mean more
integral
gain.
Power: -12 to -28 dBm depending on solvent.
Note
: The values shown in the BSMS panel are attenuations from 0 dBm.
Filter: 4 for strong solvents, 1000 for weak solvents. The numbers are not the
bandwidth in Hz but the number of averages per second. A value of 1000
is equivalent to 1 Hz, 4 is equivalent to 250 Hz.
Field: 0 to 4095. A value of 2048 means no current flowing in H0 Coil. The ideal
value is between 1500 and 2500, to allow for magnet drift. The BSMS
field has the opposite polarity, i.e increasing the value of the field DAC by
1000 steps will cause a shift left (i.e increase the frequency) by 20 ppm.