Labconco Type C1 Biosafety Cabinet Models 30468 - Manual (Page 35)

Product Service 1-800-522-7658 35
Controlling the motor’s operation with a microprocessor adds numerous
advantages. Motor speed can be efficiently controlled across a speed range
that would damage or destroy a PSC motor. Given enough microprocessor
memory and power, the manufacturer can program in any number of user-
selected programs controlling motor speed, power and even direction of
rotation. The ultimate expression of the power of the ECM was the
development of the constant volume algorithm, by General Electric, and
used in the Axiom BSC. By testing a prototype model to a variety of airflows
and filter pressures, the motor/blower can be “characterized” for that size
cabinet. This characterization allows for the creation of a model-specific
motor-blower curve. By programming the curve values into the motor during
assembly, the motor will deliver the correct volume of air as the HEPA filters
load.
Electronics
The Axiom utilizes two microprocessors. The first is part of the ECM motor,
attached to end of the motor housing, as shown in Figure 1-10. This
processor controls motor operation, and communication with the display
board. The second is located on the control board, located on the right side
wall, as shown in Figure 1-11. It controls the display and its interface to the
touchpad.
Figure 1-10
The ECM Microprocessor board is encapsulated in
epoxy to prevent moisture and dirt contamination of
the microelectronics.
Figure 1-11
The control board assembly
(located on the right side wall)