SCB20
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Parameter Min. Type Max Unit Notes
Power Amplifier Temperature
for Shut Down
165 °C
Current Limit (Power Amplifier) 3.5 A
Current Limit (shunt)
for Shut Down
1.2 A
Table9.1: Electrical Characteristics
1. The SCB20 boards are calibrated in the factory to achieve this accuracy. The uncalibrated
gain error is significantly higher.
2. The sum of all Shim currents (absolute values) of one SCB20 board must not exceed this
value. Additionally, the constraints of the power supplies must be taken into account
(including the dissipation loss of the SCB20). Therefore, the maximum available current
sum may be further reduced in rare occasions.
3. Measured with a Z-Shim (Boss-2) and an additional Resistor of 2.7 Ohms (consideration
of wiring and connectors). See the diagrams below:
Figure9.1: Step Response with Step Size of 200mA (left) and 2.0A (right)
9.3 Configurations
There are basically two standard configurations - one SCB20 providing the necessary
number of currents for BOSS1 and two SCB20 covering all other types of shim systems.
Configuration for a specific Shim System is done by loading a specific BOSS matrix. The
corresponding files are delivered with the TopSpin installation, the latest versions can be
downloaded from the ftp server ftp://ftp.bruker.ch.
BOSS1 Systems do not need a BOSS file - the predefined matrix is already available in the
ELCB software. It was theoretically possible to override this matrix by a specific file, however
there hasn‘t been any corresponding file defined so far.
All other Shim Systems (BOSS2, BOSS3, Wide Bore) require the according BOSS data to be
loaded once. This is normally handled by the TopSpin application - or it must be performed
manually during the installation. The complete BOSS data remain then in the nonvolatile
memory of the ELCB.
9.3.1 BOSS1 Configuration
One SCB20 is sufficient for any type of a BOSS1 Shim System. It is recommended to plug
the SCB20 into slot 8/9, since the H0 Current is only available at the corresponding
backplane connectors J18 and J20.
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General