際際滷

際際滷Share a Scribd company logo

Optical Encoder

Download as PPT, PDF
Hasnain Nazir Sherwani
Hasnain Nazir Sherwani

This document discusses an optical encoder which converts rotational motion into an electrical signal. It consists of a light emitting diode (LED), slotted disk, and phototransistors. As the disk rotates, light pulses from the LED pass through its slots and are detected by the phototransistors, generating a sine wave. This wave is converted into a square wave and measured to determine pulses per revolution and revolutions per minute (RPM) using a LabVIEW program, allowing rotational speed to be monitored.

1 of 12
Downloaded 173 times
Optical Encoder Group MembersGroup Members Hasnain Nazir(ME23)Hasnain Nazir(ME23) Mubashir Ayub(ME27)Mubashir Ayub(ME27) Arif Wahid(ME25)Arif Wahid(ME25) Assadulllah(ME80)Assadulllah(ME80)
Introduction An optical encoder is a complex system which converts a mechanical rotary motion (angular position or speed) into a usable electrical signal.
Optical Encoder
An encoder is a photoelectric emitter receiver pair looking through a slotted disk.
Optical Encoder
The encoder operates on the principal of optics. Light from the LED passes through the disc, the mask, and into the photo transistors. The photo transistor outputs a sine wave which corresponds to the flashing light pulses from the LED. The sine wave is then converted to a square wave into DAQ/NI ELVIS II.
Pulse rate or Pulses per Revolution is defined as the number of physical lines and corresponding spaces on the code disc. A pulse is equal to one complete 360 degree Electrical(not mechanical) square wave from an encoder.
A LabVIEW Measurement of RPM We can use the Pulse Measurements.vi to measure the period, pulse duration, or duty cycle from a waveform array.
We can convert the period measurement to revolutions per minute by inverting the period to get frequency and multiplying by 60 to get rpm. For scaling, divide by 1000 to get krpm.
Use the DAQ Assistant to collect 1000 V samples for the tachometer graph and provide an input signal array for the Pulse Measurements.vi.
Optical Encoder
Run this VI and take your motor for a spin. See and hear how responsive the motor is to a rapid change in the rpm setpoint.

More Related Content

Optical Encoder

  • 1. Optical Encoder Group MembersGroup Members Hasnain Nazir(ME23)Hasnain Nazir(ME23) Mubashir Ayub(ME27)Mubashir Ayub(ME27) Arif Wahid(ME25)Arif Wahid(ME25) Assadulllah(ME80)Assadulllah(ME80)
  • 2. Introduction An optical encoder is a complex system which converts a mechanical rotary motion (angular position or speed) into a usable electrical signal.
  • 4. An encoder is a photoelectric emitter receiver pair looking through a slotted disk.
  • 6. The encoder operates on the principal of optics. Light from the LED passes through the disc, the mask, and into the photo transistors. The photo transistor outputs a sine wave which corresponds to the flashing light pulses from the LED. The sine wave is then converted to a square wave into DAQ/NI ELVIS II.
  • 7. Pulse rate or Pulses per Revolution is defined as the number of physical lines and corresponding spaces on the code disc. A pulse is equal to one complete 360 degree Electrical(not mechanical) square wave from an encoder.
  • 8. A LabVIEW Measurement of RPM We can use the Pulse Measurements.vi to measure the period, pulse duration, or duty cycle from a waveform array.
  • 9. We can convert the period measurement to revolutions per minute by inverting the period to get frequency and multiplying by 60 to get rpm. For scaling, divide by 1000 to get krpm.
  • 10. Use the DAQ Assistant to collect 1000 V samples for the tachometer graph and provide an input signal array for the Pulse Measurements.vi.
  • 12. Run this VI and take your motor for a spin. See and hear how responsive the motor is to a rapid change in the rpm setpoint.