What is meant by Rotary Incremental Encoder Index Pulse “gating”?


qd145_sealed_open

Gating refers to the width of the Z (index) pulse relative to the A and B channels. With ungated devices the edges of the Z pulse have no hard relation to A & B.

Gating to channel A, requires the Z pulse to be high once per revolution and only when A is high.

Gating to channels A&B high requires the Z pulse to be high once per revolution and only when A AND B are high.

Gating to A creates a Z pulse roughly 180 Electrical Degrees in duration while gating to A&B creates a Z pulse roughly 90 Electrical Degrees in duration.

Gating to a smaller duration increases the precision of the Z pulse, but also requires the motion system to be able to read the Z channel at a faster rate.

Gating is sometimes required by certain drive/amplifier/controller manufacturers.

QD145 Z (Index Pulse) Specifications:

incremental-encoder-gating1
Ungated Z
Z-A/A-Z min = 0 Electrical Degrees
Z-A/A-Z max= 225 Electrical Degrees
Z width min = 180 Electrical Degrees
Z width Max = 540 Electrical Degrees

Z Gated to A
Z width min = 135 Electrical Degrees
Z with max = A true

Z Gated to A&B
Z width min = 45 Electrical Degrees
Z width Max = A&B true

incremental-encoder-gated1

Ungated Z
Z true over A&B> 45 Electrical Degrees
Z-A&B/A&B-Z min = 0 Electrical Degrees
Z-A&B/A&B-Z max= 315 Electrical Degrees
Z width min = 180 Electrical Degrees
Z width Max = 540 Electrical Degrees

Z Gated to A
Z width min = 135 Electrical Degrees
Z with max = A true

Z Gated to A&B
Z width min = 45 Electrical Degrees
Z width Max = A&B true

Any optical encoder related questions can be posted here or sent to info@quantumdev.com .

For more information on optical encoders visit the main Quantum Devices Inc. Web site at http://www.quantumdev.com.

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About Quantum Devices Inc.
Quantum Devices, Inc. (QDI) Barneveld, WI, was established as a Wisconsin corporation in October 1989, as an outgrowth of activities in the general area of optoelectronics. The main goal of QDI is to provide customers with a complete source for all stages of product design and development, starting from concept to a marketable commodity. These products include application specific Silicon Photodiodes, Optical Encoders and Light Emitting Diodes (LED) for commercial, industrial and medical applications. QDI's photodiodes and LED's are used in instrumentation for photosynthesis and photobiological research, biomedical and medical instrumentation for measuring blood sugar levels (glucometer), oxyhemoglobin and pulse rate (pulse oxymeter). One of the most dramatic products developed at QDI was the application of LED lighting systems for use as the light source for Photodynamic Therapy (PDT). Sales of QDI products include both domestic and international markets. Quality and reliability are very important concepts in maintaining our company wide commitment to overall product performance. Quality simply means continuous process improvement. We are committed to continually increasing our product excellence through increased quality and reliability. Quantum Devices, Inc. is ISO 9001 certified and the ISO Standard will provide the guidance for the vital function of maintaining our commitment to constantly improve our product quality. Quantum Devices is now proud to introduce it's new line of rotary encoders. Incorporating QDI's patented sensor technology, our QPhase™ Family of Encoders feature high resolution, increased frequency response and superior reliability over temperature (0 to 120 degrees C). QDI incremental and absolute encoders set a new standard and are backed by a 2 year factory warranty. We invite you to request an evaluation unit, additional information or price quotations. Mission Statement Quantum Devices is dedicated to the principle that light provides the power for all life on earth. We believe the quality, delivery and control of light is essential to the wellness of man and his advancement into the future.

2 Responses to What is meant by Rotary Incremental Encoder Index Pulse “gating”?

  1. Pingback: Understanding Incremental Encoder signals « Quantum Devices INC

  2. Pingback: Optical Encoder Waveform Triggering « Quantum Devices INC

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