Digital To Analog Converter DAC Motor Driver Position Sensor Display Unit

Motor DC Position Control Based on Moving Speed Controlled by Set Point Changing Using Fuzzy Logics Control System – Andino Maseleno, Fajar Hayyin, Hendra, Rachmawati Lestari, Slamet Fardyanto, Yuddy Krisna Sudirman ISSN 1858-1633 2005 ICTS 165

4.1. Digital To Analog Converter DAC

The planning system is using 1one DAC 0832 function as input voltage control for motor driver. Next is DAC testing table with variety binary input. Table 2 DAC testing table No. Input Binary Output V Measured 1. 0000 0000 2. 0000 0010 - 2.42 3. 0001 0000 - 2.23 4. 1000 0000 0.65 5. 1111 1111 2.6

4.2. Motor Driver

Motor driver circuit input is Digital to Analog Converter DAC output. Motor driver circuit process analog signal in voltage from DAC to control appropriate motor spinning. For direction control application using microcontroller, is using transistor as in figure 12, contained 4 transistors with Darlington configuration in each transistor contained 2 transistors which is Tip 31A and C9013 for NPN, and Tip 32A and C9012 for PNP.

4.3. Position Sensor

There are 2 sensors to distinguish left or right spinning direction. Sensor circuit contained optocoupler, encoder, lm358 as comparator, and 74HC14 schmit trigger. Optocoupler Optocoupler is an optic sensor, which is capable to change light effect into electric pulse. Inside the optocoupler contained infrared LED and phototransistor. If optocoupler activated, it able to transfer electric energy from infrared LED to phototransistor. For further if infrared light is block then basis collector obstacle getting bigger so collector current decrease and collector voltage closing 0 volt, electric transfer will cut off. Figure 12 Two direction position sensor output Encoder Plastic plate giving black and white stripes on plate fingers with same distance in 180 lines. Each line will read by optocoupler in pulses. To distinguish direction then the line made up and down with different pattern. 74HC14 Schmitt Trigger IC 74HC14 function as square wave inverter amplifier. The imperfect square wave related to Schmitt trigger 74HC14 input, in order to gather the perfect square wave.

4.4. Display Unit

To display set point and motor position using 6 seven segment common cathode. IC input Port came from port B PPI 8255 used as data sender. Display unit using IC CMOS 4511 with BCD input and as decoder that separate set point display and position used by 74HC138. The output data from microcontroller in 8 bit binary will be split into 2 parts. First part contains 4 bit A – D used as IC CMOS 4511 input to display at seven segment. The next 4 bit D0 – D3 used as IC 74HC138 input to address which seven segment will turn on.

4.5. Testing Result Table