Pcba-Base - Bernina 330 Service And Maintenance Manual

2.3 PCBA-Base

The PCBA-Base is based on SMD (surface-mounted device) technology. The SMD components make a
highly compact circuit configuration possible.
SMD-populated printed circuit boards cannot be repaired with a conventional tool!
The microprocessor on the PCBA-Base
receives an analog signal from the foot
control which it converts into a digital
signal and relays as a reference setting.
The motor speed is set to the required
value by a target/actual comparison.
When the foot control is released (target
value zero) the microprocessor activates
the electric brake. The motor decelerates
very quickly, and stops at the requested
needle position.
After the machine is switched on, the
stepping motors are in a random position.
The microprocessor-control memory can
also contain a random value. In order to
have defined conditions, the stepping
motors are rotated into their defined
positions through a command from the
microcomputer, and the position value is
set to zero in the memory. It is possible to select and sew each stitch program with this initial position.
The PCBA-Base controls the processes between the individual motors. It analyses the sensor signals and
displays the results on the screen. The display and the position sensors are built into the PCBA-Base
a) Interface buttonhole sensor
b) Interface LED Sewing light
c) Interface Winder Motor
d) Interface Stepping Motor Stitch Width
e) Interface Stepping Motor Stitch Length
f) Interface Main Motor
g) Connection cable connector to PCBA-Power
h) Interface PCBA-RET
i) Light prism for synchronization disc
j) Microprocessor
BERNINA International AG · Seestrasse 161 · CH-8266 Steckborn · Switzerland
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1) Speed control
2) LCD display
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