BASF 6106 - Drive Motor Control

2.2.3 DRIVE MOTOR CONTROL (FIG. 2-18)
The drive motor used in the BASF 6106 and 6108
is a Oe-motor. Start and stop of the motor is
controlled from the host system by the inter-
face signal MOTOR ON. After the drive motor
is started, a delay of 0.5 sec is needed to
allow proper
motor speed, before reading or
writing. The speed of the drive motor is con-
trolled by the integrated circuit ESM 227. It
holds the EMF of the drive Oe-motor to a con-
stant value. Because the speed of the drive
motor
is proportional to its EMF, the speed
.12 V
will be also constant. With the potentiometer
R47 the drive motor must be adjusted to a disk
speed of
300 RPM. The output voltage of the ESM
227 is controlled by the MOTOR ON-signal at
Pin
12 of the chip. If MOTOR ON i5 inactive (low)
Tl will be closed and holds T2 open. The drive
motor stops.
An active MOTOR ON-signal opens Tl
and T2 is enabled. The drive motor is running and
regulated, so that the Flexy Oisk is rotating at
300 RPM.
T10 limits the drive motor start current to 0.7 A.
J/P6
~------~-----------------+---------; 4
I
RPM ADJUST
I
R 83
FIGURE 2 - 18 DRIVE MOTOR CONTROL
2 - 14