
Motor assembly for adjustment
 RS-380PH is used for the main motor and
RE-280 is used for speed detection. Both
motors are made by the MABUCHI MOTOR Inc. in Japan. Because this assembly
is to adjust a speed control, both motors are directly connected using the
plastic gear. When the center of both motors isn't right, there is
possibility that the gear comes off the shaft of the motor. Pay
attention.

Speed control parameter
The speed control flow of the circuit
this time is shown with the left figure. At the
control circuit, the following three parameters should be
adjusted.
Speed reference value
Control rate value (Deceleration and
Acceleration)
Control period
These
values will be changed with the characteristic of the main motor and the
speed detection motor. In case of the motor, even if the drive electric
current changes, the rotational speed doesn't shift immediately. It takes
time. In case of the small motor, because the mass of the rotor is small,
the rotating speed shifts quickly by the change of the drive electric
current. In case of the big motor, it takes time to change the rotating
speed after changing the drive electric current. The rotating change time
can be made short if the change of the drive electric current makes big.
However, when the change of the drive electric current is too big, the
rotating speed can not be made constant.
Speed reference value is adjusted at the value to set
to speed. Control rate value is adjusted at the
value to set to change. Control period is adjusted at the value
to set to CCPR2H
and CCP2L
registers.
When making a program, I thought
that the speed detection period didn't influence a control characteristic.
Therefore, I didn't make a period value label.
When the control rate value is big
When the detection period is short and
the control rate value is big, the rotating speed of the motor changes
big. When the rotating speed of the motor is above the reference value, a
deceleration control is done.(It reduces an drive electric current)
However, because of the mass of the rotor of the motor, it doesn't react
immediately. Even if it begins deceleration by the A point, the rotating
speed of the motor continues to rise in a little while. In case of the B
point is above the reference value, a deceleration control are done
moreover. In case the speed is above the reference value, the drive
electric current is increased in every period. The deceleration value at B
pont is bigger than A point. Therefore, it continues to decelerate even if
it falls below the reference value. When detecting rotating speed below
the reference value in the C point, acceleration is begun. It is more
strongly accelerated every period like the deceleration. It repeats above mentioned operation and the rotating speed of the
motor changes widely. The speed detection period is
short, the turning change appears conspicuously.
When the control rate value is small
 When the control rate value is
small, a comparatively stable speed control is done. However, the
stability to the load change becomes weak. It takes time until it returns
to the reference value after the rotating speed declines by the
load.
Influence with speed detection
period
You may seem to be able to do a tender
control if you make a speed detection period short. However, it doesn't
meet. But, this relation is in case of my control circuit. In case of the
other control system, it doesn't apply. In case of
my control circuit, it increases a deceleration value or an acceleration
value every period. Even if a control electric current is changed, the
rotating speed doesn't sometimes change immediately. This is because of
the mass of the rotor. When the speed detection period is short, the motor
drive electric current changes widely. As a result, the change of the
rotating speed becomes big. When the detection
period is long, the band of the drive electric current becomes small. As a
result, the change of the rotating speed becomes small. When the detection period is long, the controllability to the load
change declines. However the bad influence comes out when too
long.

Turns on order of the power
A power is turned on after connecting a motor and a control system.
It turns on the motor first and after that, it turns on the controller.
When the power of the motor and the control circuit is the same, it isn't
made. The reason for turning on the power in the order is hereinafter.
When turning on the controller first, because voltage isn't applied to the
speed detector, the control circuit increases a drive electric current and
becomes a maximum drive electric current condition finally. When turning
on the power of the motor in this condition, a motor is driven in the
maximum electric current. As a result, the motor becomes reference speed
gradually after beginning to turn forcefully. When this operation is not a
problem, you don't have to be conscious of the turning on
order.

Adjustment of the control
parameter
You consider the above and adjust the
control parameter. It is troublesome a little.
Adjustment of speed detection
period
When this value isn't appropriate, the rotating speed
of the motor isn't stable. In the case, it attempts to make a period
long. It adjusts by the value of CCPR2H and the CCP2L
registers.
Adjustment of reference value
It sets a variable resistor on the low-speed
side(Left fullness) and it adjusts the low-speed value of the
motor. It adjusts by the value of speed. To change the speed range to adjust with the variable resistor,
the value of R12 should be changed.
Adjustment of control rate
value
When making this value big, the change of the drive
electric current value at each period becomes big. When the load
changes big, it makes this value big. I set to the minimum
value. It adjusts by the value of change.
Please try variously because
these values change with the motor and the detector to
use.
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