16 pulse rotary motor encoder

[The_UnforgiveN]

Hi all,

I have an incremental rotary encoder. It says it's 16 pulse with A & B channels. But in the servo driver tuning software it asks me the value of the encoder in terms of "lines/rev".

What should "lines/rev" equivalent of a 16 pulse incremental rotary encoder?

Thank you

 

[MikeMl]

I wonder if it is expecting an absolute encoder, where say a (0-255) 8-bit encoder would have eight "lines"? How many encoder-input pins does the controller box have?

 

[House0Fwax]

It sounds like the software is expecting the kind of encoder found in ink jet printers.
The kind that read a disc with many lines per revolution
https://www.electro-tech-online.com/custompdfs/2009/12/Agilent_Optical_Encoders.pdf

 

[jbeng]

I expect the lines per rev parameter they are referring to is equivalent to pulses per rev. In this case, it sounds like 16.

Jeff

 

[MikeMl]

The 16 Pulse per rev encoder is actually capable of encoding 4X16=64 positions because of the quadrature relationship between the two channels. So is this a 16 line encoder, or is it a 64 line encoder?

 

[Mr RB]

Lines per rev is exactly what it says. A quadrature encoder with 16 lines on the glass disk produces max of 16x4 "edge events" per rotation. One of the encoder outputs would make 16 high pulses per rotation.

 

[gary350]

The rotory incoder you have should several glass disc mounted on a shaft that rotates. The first disk will be divided into 2 parts, 1/2 black and 1/2 clear.

The second disc will be divided into 4 parts, 1/4 black, 1/4 clear, 1/4 black, 1/4 clear.

The third disc will be divided into 8 parts, 1/8 black, 1/8 clear, 1/8 black, 1/8 clear, 1/8 black, 1/8 clear, 1/8 black, 1/8 clear.

The 4th disc will be divided into 16 parts, 1/16 black, 1/16 clear, 1/16 black, 1/16 clear, 1/16 black, 1/16 clear, 1/16 black, 1/16 clear, 16 parts, 1/16 black, 1/16 clear, 1/16 black, 1/16 clear, 1/16 black, 1/16 clear, 1/16 black, 1/16 clear.

The 5th disc will be divided into 32 parts.

The 6th disc will be divided into 64 parts.

The 7th disc will be divided into 128 parts.

An so on. It depends on the encoder as to how many disks it will have and how accurate it is designed to be but most are accurate to .0005" of an inch. All an encoder does is provide information to the computer that can be used to tell the system the exact location of a moving object.

 

[jbeng]

What gary350 described would be a type of absolute encoder. However, I have never seen an encoder with more than one disk inside. They may very well exist, but I have never seen one - especially one with several disks. I have always seen multiple code tracks etched on one disk.

For a servo system such as one the o/p wrote about, I expect the encoder is the incremental type.

Regarding number of lines/rev of an encoder, here are a couple of glossary excerpts.

The first is from: Dynapar Encoder Glossary

"LINE COUNT
Line count is the number of equally spaced radial lines per 360 mechanical degrees on the incremental encoder code disk."


The second is from: **broken link removed**

"Line Count
This is often used to mean resolution. It refers to the number of lines that are contained in the code pattern of the code disk on an incremental encoder."


Jeff