Panasonic BB-HCM547A, Service Manual

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BB-HCM547A
4.6. Pan and Tilt Motor Control Circuit
PAN drive motor and TILT drive motor are driven under the control from the CPU (IC101).
[PAN drive control]
PAN drive control circuit is mounted on the Main board.
For the PAN drive control, the CPU (IC101) generates a variety of pulses that are applied to the PAN motor diver (IC608) to con-
trol the speed and direction of the rotation of the motor. In addition, the reference voltage is exchanged and it is generated the
PAN motor diver (IC608) by CPU(IC101) output port and the current to the PAN motor is used to control the torque of the PAN
motor and to the W1-2 control drive of the motor.
The W1-2 control drive is the method to increase the rotational resolution of the motor, and with this method of the W1-2 control
drive the accuracy of 1.875
°
(7.5
°
/4) has been achieved for the PAN motor minimum step angle of 7.5
°
. The motor control signal
from the motor driver (IC608) for the PAN drive is applied to the PAN drive motor via the 4-pin connector (CN653)
In the position control, the home position for the PAN control is detected by the PAN sensor (IC606; photo coupler) when the
power is turned on, and then the position is open-loop controlled by the software. In order to remove variations among products,
the output from the PAN sensor (IC606) is input into the comparator (IC607) and the output (PAN_S) from the comparator is
detected in the CPU (IC101).
The motor drive power supply (VM voltage) for the PAN drive motor driver (IC608) is +12 V that is supplied from the IO board.
[TILT drive control]
The TILT motor driver (IC403) and TILT sensor (IC401) which are The TILT drive control circuit are mounted on the TILT board.
For the TILT drive control, the CPU (IC101) on the Main board generates a variety of pulses that are applied to the TILT motor
driver (IC403) to control the speed and direction of the rotation of the motor. Since the TILT drive control does not require such
rotational resolution as required in the PAN drive control, but the “W1-2” control method is used. In the TILT drive unit, the accu-
racy of 1.875
°
(7.5
°
/4) has been achieved for the TILT motor minimum step angle of 7.5
°
. The motor control signal from the
motor driver (IC403) for the TILT drive is applied to the TILT drive motor via the 4-pin connector (CN403).
In the position control, the home position for the TILT control is detected by the TILT sensor (IC401; photo coupler) when the
power is turned on, and then the position is open-loop controlled by the software. In order to remove variations among products,
the output from the TILT sensor (IC401) is input into the comparator (IC607) on the CPU board and the output (TILT_S) from the
comparator is detected in the CPU (IC101).
The motor drive power supply (VM voltage) for the TILT drive motor driver (IC403) is +12 V that is supplied from the IO board via
the Main board.