Used to achieve position control of optical technology provides a with a fixed landmark points combination of linear or rotary motion components to achieve a simple and repeatable movement method of , this method not only spend much money, and ease of design. Figure 1 shows the simple and basic design to achieve in order position control , which uses with a pair of photodiodes in parallel the work of a power op amp fast response time. Thus achieving a components small number of system , can be clearly defined work environment, high reliability , accuracy and repeatability. Figure 1 shows circuit using a power op amp a pair of photodiodes differential output combine to drive motor to the right the direction of rotation until the two photoelectric currents are equal , thereby achieving sequential position control . when you Moment to a fixed input current switch to the amplifier input, the amplifier drives the motor in the desired direction of rotation will cause the motor the two landmarks between movement . When does not meet the mark points the input current is cut off when , CF on the charge continue to electric motor power. to ensure that the motor to Required the direction of continued turn , when the first photocell is illuminated , the electric motor to receive the optical management output generated by power .

When the second photocell is illuminated when its current the motor reverses , so the system lock flag point . Using the Differential configuration to eliminate the optoelectronic devices the temperature of instability and time instability of caused by the the error . The system uses a simple switch ( Figure 1) to produce forward and reverse two kinds of rotation. As the motor response time and system inertia in different applications vary widely, you can applications select CF and RF to achieve the suitable damping . CF must be small enough so that the motor the sign point of through the the second photocell before the realization of reversal , otherwise , the system will continue to campaign to the next flag point. If CF the value of is too small , then serious overshoot or oscillation , leading to transmission failure , or even burning motor.

Optical circuit a power op amp to achieve sequence of position control.

To be too dilutive to a minimum, Figure 1 RF1 and RF2 to the control loop stabilize gain of 1 point. You can also apply a braking force to shorten the response time, is with the RL and CL a lead network , so that the amplifier the sensor output of changes to fix the motor drive. Figure 1 motor has 14V of the EMF ( electromotive force ), and can reverse when conduction the output transistor with 46V voltage. This time, power the worst -case consumption , you have to control SOA ( safe operating area ) verification of the power consumption.

Shows beam the sensor the best calibration of . You just the beam aim for each photodiode of the work area , you can achieve the best calibration. Beam must be irradiated to the of each photodiode photosensitive area half. When it is determined "hole "in size, to consider beam position the photodiode the distance between . If the beam is too large, the sensor in positioning the range does not produce any change. Beam is too small will be in Optical sensitive area between along the centerline to produce a nonlinear transfer function. This nonlinearity makes it difficult to select the circuit the damping capacitor value of CF capacitance , and require the use of brighter light.