Encoder Basics

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Encoder Basics

Post by admin »

Acorn Encoders Basics


1. Encoder Type:
Centroid Acorn CNC controller Encoder input requires quadrature, differential encoders for Spindle encoder use which operate on 5VDC. This is the most common type of encoder. Encoders labeled "TTL type" (single ended, non differential) are unsuitable, and fortunately are rare and converter boxes are not recommended.

2. Encoder Signals:
a) The following signals must be present and wired: A, /A, B, /B, Z, /Z, +5VDC and ground.

Note: The Z channel is sometimes labeled as I, C or "marker". The "/" symbol may also be
expressed as "-", "NOT" or "!" or a line over the letter, it means the signal is the complement
(opposite) of the channel specified.

b) Signal levels:
The "low" signal level must be less than 0.5 VDC and the "high" signal level must be at least 3.5 VDC. ACORN supplies around 50mA that is typical of most encoders.

3. Encoder Resolution:
Typical Machine tool applications (milling machines, lathes and routers) require at least 1000 line (4000 counts per rev) encoders, We recommend any where from 1000 to 2000 line (= 4000 to 8000 counts per rev) encoders. To achieve reasonable accuracy for good threading and rigid tapping.



Encoder wiring at the Acorn
DB9 Body = Cable Shield

Pin Function
1 No Connection
2 GND
3 Z\
4 A\
5 B\
6 Z
7 A
8 B
9 +5 VDC
db9m-solder side.gif
db9m-solder side.gif (1.3 KiB) Viewed 41899 times
db9m-pin side.gif
db9m-pin side.gif (1.16 KiB) Viewed 41899 times
encoder cable.JPG
encoder cable.JPG (21.75 KiB) Viewed 20404 times
related Acorn Spindle Encoder thread.
https://centroidcncforum.com/viewtopic.php?f=60&t=1925
cnckeith
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Re: Encoder Basics

Post by cnckeith »

We sell 2000 line (8000 counts per revs) encoders that accept common sized motor encoder shafts on our website.

2000 Line Encoder (8000ppr)
This differential encoder not only suppresses noise in the system that can be harmful to encoder signals, but also outputs a quadrature signal giving 8000 counts per revolution of the motor. This is ideal for machines already equipped with DC brush servos to enhance the speed and precision of the machine. Available in 6 mm, 1/4", 3/8", and 1/2" hollow shaft sizes
comp_encoder_large.jpg
comp_encoder_large.jpg (44.95 KiB) Viewed 41828 times
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
Centroid_Tech
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What are the wire colors of the encoder pigtail?

Post by Centroid_Tech »

Question: Somehow the encoder pigtail was damaged. What are the wire colors of the encoder pigtail?

Answer:
Pin Signal Color
1 A Blue
2 A/ Blue/Black stripes
3 B Green
4 B/ Green/Black Stripes
5 Z Violet
6 Z/ Violet/Black Stripes
7 Vcc Red
8 GND Black
9 Shield Heavier Black wire
When requesting support, please ALWAYS post a current report. Find out how to take a report from your Acorn, CNC11 or CNC10 system here: https://www.youtube.com/watch?v=Ecvg0VJp1oQ.

If your question is PLC, Macro or program related, please also post a copy of the program or macro as well.

Without the above information we may not be able to help and/or reply until the required information is posted..
Centroid_Liviu
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Re: Encoder Basics

Post by Centroid_Liviu »

Encoders labeled "TTL type" (non differential) will not work with our control. We have 2000 line (8000ppr) encoders in 6 mm, 1/4?, 3/8?, and 1/2? hollow shaft sizes available if you need to swap yours out.
When requesting support READ THIS POST first. https://www.viewtopic.php?f=60&t=1043

Please ALWAYS post a FRESH report. To make a report: https://www.youtube.com/watch?v=Ecvg0VJp1oQ.

(We pride ourselves on providing timely solid technical support but, without good information we may not be able to help and/or reply until such information is posted.)
Centroid_Liviu
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Re: Encoder Basics

Post by Centroid_Liviu »

You would need a differential quadrature output the same as the encoders (minus the Z channel). Do you have a manufacture and model number for the scales you wish to use? Please note that each axis will still need an encoder signal.
When requesting support READ THIS POST first. https://www.viewtopic.php?f=60&t=1043

Please ALWAYS post a FRESH report. To make a report: https://www.youtube.com/watch?v=Ecvg0VJp1oQ.

(We pride ourselves on providing timely solid technical support but, without good information we may not be able to help and/or reply until such information is posted.)
cnckeith
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Re: Encoder Basics

Post by cnckeith »

10 mm encoders are in stock. we also have 10,000 line encoders in stock as well. call or email for shaft sizes available.
also proper shielded encoder cable and shielded vfd with drain is in stock at very affordable prices.
also new Oak and ALlin1dc schematics sets are available along with the latest Oak and Allin1dc installation and operator manuals on this page
http://www.centroidcnc.com/operator_manual.html
Attachments
cable.JPG
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
cnckeith
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encoder mounting video, servo motor encoder retrofit

Post by cnckeith »

new video on encoder mounting by martyscncgarage.

https://youtu.be/bd2GzrBAn9A?list=PLXhs ... STDELrnNx2
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
cnckeith
Posts: 7539
Joined: Wed Mar 03, 2010 4:23 pm
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Contact:

Re: Encoder Basics

Post by cnckeith »

I could find on this series of encoder actually publishes the low and high signal level specs! So, what's the real deal with all this signal level stuff?!

Thanks in advance for any assistance you can provide!
[/quote]

3.5 to 5 volts is what you want.. you get any lower than that and you'll get differential errors.
attached is dynapar endcoder spec sheet. centroid uses the 2000 line (8000 count per rev encoders) as a minimum spec encoder.
I've been personally using a Quantum Devices 10,000 line (40,000 count per rev) encoders on all installations with Allin1DC for the last few years with great results.
attached is a pdf photo. you can buy these from centroid or other sources as well and that is what i recommend to use.
Attachments
encoder spec sheet 2.PDF
(486.92 KiB) Downloaded 510 times
encoder spec sheet.PDF
(634.55 KiB) Downloaded 485 times
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
DICKEYBIRD
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Location: Collierville, TN USA

Re: Encoder Basics

Post by DICKEYBIRD »

Does the recommendation for at least 1000 line encoders apply to mill & lathe spindles as well as axis servos?

edited to add: Sorry guys, looks like I need to RTFM more thoroughly before asking questions! I just saw that the recommended encoder for the Acorn is 2000 lines.
Milton in Collierville, TN

"Accuracy is the sum total of your compensating mistakes."
martyscncgarage
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Re: Encoder Basics

Post by martyscncgarage »

Milton,
I would not go less than 1000, 2000 is better spindle or servo motors
automationdirect.com is a good source for encoders as is Centroid. Try and stay away from ebay, its not worth the trouble....
Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
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