Avance II
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General description
Avance II is series of Bruker BioSpin Group produced Avance NMR spectrometers (consoles) with up to 8 RF (Radio Frequency) channels, plus lock channel. This console has a modernized version Avance II+ also which was equiped with IPSO (Intelligent Pulse Sequence Organizer) and was transition model to Avance III console. Avance II was produced for NMR spectrometers from 200 to 900 (950) MHz. Around 2007 y. Avance II was replaced with Avance III series of consoles.
The main difference of Avance II from earlier Avance series of spectrometer consoles is introduction of the DRU (Digital Receiving Unit) and the more extensive integration of different spectrometer functions into one physical block (device). Together with the application of DRU, instead of the separate ADC like were SADC, HADC or FADC the new RXAD board which integrates together receiver and ADC was also introduced. Avance II uses oversampling for the signal analog-digital conversion, and the digital lock system working on the same referencing frequency with which quadrature detector of observe channel is feeded. This allows to get spectrum reference frequency on the basis of lock signal and get correct chemical shifts scale for spectrum automatically. The console is controlled by the Bruker TopSpin software (not supported by XwinNMR).
Specifications
Resolution of the frequency generation is <0.005 Hz and <0.006 deg for its phase. Minimum time for digital phase and amplitude setting is 50 ns and for frequency setting is 100 ns. Time for the frequency and phase real switchings is <300 ns for frequency and phase, <100 ns for the amplitude setting. Timing resolution for operations 25 ns, system clock timing is 12.5 ns. Dynamic range of ADC up to 20 bits. Frequency stability <3X10-9 per day and <1X10-8 per year.
Architecture
Avance II console is implemented in three different chassies: MicroBay (only 200-400 MHz and up to 3 channel configuration), OneBay (up to 4 channels and 600 MHz?) and TwoBay (Up to 8 cannels and 900 (950) MHz, and for MAS). The main parts of the Avance II console are AQS (AQuisition System) or newer version AQS/2 and BSMS/2 (Bruker Smart Magnet System). In TwoBay configuration two AQS-s modules can be installed simultaneously which is used for additional RF channels.
In AQS or AQS/2 are located the (main) devices (blocks): DRU (Digital Receiving Unit) or DRU-E (used starting from 700MHz and for solids), RXAD (Receiver with integrated Analog to Digital converter) or RXAD-BB (for solids), REF (REFerence Unit) or REF/2 (same, but for two AQS-s), SGU (Signal Generation Unit), FCU3 (Frequency Control Unit) or FCU4, TCU3 (Timing Control Unit), ACB (Aquisition Control Board) plus PSD board or ACB-S (in the case AQS BLA-s), GCU (Gradient Control Unit), CCU10 (Communication Control Unit)or CCU11, PSU (Power Supply Unit) units, PSM1 (Power Supply Module) and PSM2 or PSM5 . AQS/2 can also contain internal amplifiers (BLA2BB, BLAX300, only for MicroBay configuration), preamplifiers (PREAMP XBB and PREAMP 1H2H and Cover module, used only in MicroBay configuration), and ROUTER3/5 (Router),PSD/3. AQS/2 can contain more than one (except DRU, REF, and some others) of each of those units.
BSMS/2 contains: ELCB (Extended Lock Control Board) or CPU/3 (Central Processing Unit) plus LCB (Lock Control Board), SLCB (Sample Level Control Board), GAB (Gradient Amplifier Board), PSB (Power Supply Board), SCB13 or SCB20 (Shim Control Boards), BVT (Bruker Variable Temperature), L-TX (Lock Transmitter), L-RX (Lock Receiver), 2H-TX (Lockswitch), PNK (console pneumatics).
Additionally, depending on configuration, Avance II console chassis can be configured with various power amplifiers (BLA), differnt VTU (Variable Temberature Unit), MAS devices, etc.
To the console external devices, like HPPR (High Power Preamplifier) or HPPR/2, KBC (keyboard), PC (computer), sample changer and others, are and can be connected.
Maintenance
Cleaning periodically the console filter located in the console front door and maintaining the proper room temperature are essential. Apart from this check the helium boil off rate of the magnet.
Bugs
1) There are observed problems with locking and lock signal displaying, when the system is up a long time. The BSMS or console reboot solves this problem.
2) In the case of longtime experiments with rapid pulsing, there are observed problems with the communication with AQS (probably with DRU unit in it). During of the aquisition the realtime FID and spectrum can't be monitored on screen after some time (after around 1-2 million scans) or the communication fails completely and after this the new aquisition can´t be started at all. The AQS or Console reboot solves this problem.
3) There are problems with peak picking in TopSpin (version ?). The peaks are not marked during this process sometimes. To overcome this problem type <sr> in the command line.
4) After the complete power failure the console must be booted (switched on) for the first and then the computer running Win XP with Topspin 2.0. In the another order TopSpin cant connect with BSMS correctly and the lock will absent for the program.
