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What is meant by Rotary Incremental Encoder Index Pulse “gating”? June 11, 2014

Posted by Servo2Go.com in Technical Support Information.
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Quantum Devices Optical Encoder

Quantum Devices Optical Encoder

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

More information on ‘Quick Ship’ Industrial Rotary and Modular Shaft Encoders can be viewed at-

http://servo2go.com/supplier.php?id=1057843244

For more information please contact:

sales@servo2go.com
Toll Free Phone:   877-378-0240
Toll Free Fax:       877-378-0249
www.servo2go.com

 

Tags:  Encoder, Incremental Encoder, Absolute Encoder, Single-Ended Encoder, Differential Encoder, Servo2Go, Quantum Devices

 

 

Finding the Index on an Incremental Encoder with a DMM January 31, 2013

Posted by Servo2Go.com in Product Video's, Technical Support Information.
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Sometimes you don’t have the right tools to do the job.

Lets say you needed to identify where the index pulse was firing on your incremental encoder, but you left your oscilloscope in your other jacket pocket, and now all you have on hand is a DMM.

Well fear not, finding the index with a multimeter is possible although a bit tedious.

The index fires once per revolution and at higher line counts this makes it VERY easy to miss.   Since there is some delay in a multimeter’s display time, you will need to rotate the encoder very slowly to catch a change in voltage level.

The Blue box has a nine-volt battery inside that I regulated down to 5Vdc for the encoder power.   I have pulled out connections to ground (Black wire) and the index channel (Orange wire).  When the index fires, the voltage will go from zero to five volts.

More information on the encoders from Quantum Devices can be found at the link below-

http://www.servo2go.com/supplier.php?id=1057843244

For more information, please contact:

Editorial Contact:

Warren Osak
sales@servo2go.com
Toll Free Phone:  877-378-0240
Toll Free Fax:   877-378-0249
www.servo2go.com