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Case Studies
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| Elmo
Customer Case Study - GE Medical Systems |
| ELGEMS, a wholly-owned subsidiary of GE Medical Systems, was searching for the means to reduce production
costs in its Millennium VG series Gamma camera, while at the same time maintaining top accuracy and efficiency. |
| The Millennium
VG camera performs highest-quality functional anatomic
mapping. It contains a complex array of devices that enable
the patient to sit or lie on a movable table while the
camera performs real-time automatic body contouring. Imaging
is performed by two Nal detector assemblies with high-precision
collimators mounted on the gantry. The collimators incorporate
variable geometry detectors that feature 90° and 180°
positioning for complete anatomical coverage. |
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| The ELGEMS
Millennium VG PET Scanner |
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| In order to control
the various motors driving the movable table and the adjustable
collimators along the various axes, several drive controllers
were needed. Such a configuration tended to be both costly
and space consuming. What was needed was a compact and
cost-efficient assembly of multi-axis drivers that could
concurrently control the scanner motors while guaranteeing
the highest level of reliability and functionality. |
In order to meet the special requirements of the Millennium VG scanners, Elmo
decided to design an innovative assembly - the ELG-2000 - that consists of two separate drive units:
the ELG-15/55 and the ELG-15/200. The two units are derived
from Elmo's field-proven Violin
series of miniature servo amplifiers for DC brush motors.
Each unit is a multi-axis controller containing three current amplifiers for three different axes, a built-in
power supply with a single-phase AC input, a DC-to-DC converter and a MOSFET-based shunt regulator for 15A current. |
| The entire ELG-2000
assembly is therefore capable of controlling six axes in the
Millennium VG scanner: two axes for the movable table, and two
axes for each collimator. The assembly can be further enhanced
in the future to incorporate more drive units to provide added
multi-axis motion control. |
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| One
of the two ELG-2000 units. The two units together
provide simultaneous control over six motion axes. |
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| ELGEMS
estimates that incorporation of the ELG-2000 assembly into the
Millennium VG scanners has provided savings of 10% in production
costs, stemming from reduced assembly time and lower component
prices. The miniature system, one-fifth in size of the drive
previously used, can be quickly and easily mounted And just
as important: a major side benefit of the ELG-2000 assembly
has been a significant enhancement in system performance and
reliability. |
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