Encoder Basics

All things related to Centroid Oak, Allin1DC, MPU11 and Legacy products

Moderator: cnckeith

BigWillieStyle
Posts: 7
Joined: Wed Nov 29, 2017 7:26 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Encoder Basics

Post by BigWillieStyle »

Question

Lead, Pitch, TPI all refer to different things but numerically are all equivalent?

*Note in below example TPI is actually 5.08 according to my arithmetic.

5mm Lead = 5mm Pitch = 5 TPI*

Is this correct?
frijoli
Posts: 593
Joined: Tue Sep 12, 2017 10:03 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: Yes
CNC12: Yes
CNC11: Yes
CPU10 or CPU7: No
CNC Control System Serial Number: 1030090099
Location: Outside Winston-Salem, NC
Contact:

Re: Encoder Basics

Post by frijoli »

woffler wrote: Tue Jan 02, 2018 2:11 pm Hi all ,i have a 16 bit encoder differential driver receiver it says on my servo motor for my spindle ,with A+A-,B+B-,Z+Z- it is a 1.8kw servo motor from DMM tech that i use on my lathe .
I was wondering if it would interface with the Acorn board ?
The DMM servo encoder out will work with Acorn.

Clay
Clay
near Winston-Salem, NC
unofficial ACORN fb group https://www.facebook.com/groups/897054597120437/
woffler
Posts: 15
Joined: Tue Jan 02, 2018 12:41 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none
Location: Three Points , Az

Re: Encoder Basics

Post by woffler »

Thanks for the reply Clay
tblough
Posts: 1142
Joined: Tue Mar 22, 2016 10:03 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: Yes
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 100505
100327
102696
103432
7804732B977B-0624192192
Location: Boston, MA
Contact:

Re: Encoder Basics

Post by tblough »

BigWillieStyle wrote: Fri Jan 05, 2018 1:03 am Question

Lead, Pitch, TPI all refer to different things but numerically are all equivalent?

*Note in below example TPI is actually 5.08 according to my arithmetic.

5mm Lead = 5mm Pitch = 5 TPI*

Is this correct?
BigWillie, lead and pitch are the same. TPI is not - it is the inverse of the others. A 0.2" pitch is 1/0.2 = 5 TPI.

Pitch is how far a screw advances in one turn. TPI is turns per inch. So if one turn moves 0.2 inches then 5 turns move one inch. Metric screws are normally specified based on pitches. Imperial screws are classified on turns per inch.

Your example gives the false impression they are equivalent only because 5mm is close to 0.2" but not exactly. 5/25.4 = 0.19685“. 1/0.19685 = 5.08 turns per inch.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
DICKEYBIRD
Posts: 530
Joined: Sat Jul 08, 2017 7:38 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: n/a yet
Location: Collierville, TN USA

Re: Encoder Basics

Post by DICKEYBIRD »

woffler wrote: Tue Jan 02, 2018 2:11 pm Hi all ,i have a 16 bit encoder differential driver receiver it says on my servo motor for my spindle ,with A+A-,B+B-,Z+Z- it is a 1.8kw servo motor from DMM tech that i use on my lathe .
I was wondering if it would interface with the Acorn board ?
Remember that the servo motor must drive your spindle at a 1:1 ratio...no belt reduction.
Milton in Collierville, TN

"Accuracy is the sum total of your compensating mistakes."
cncsnw
Posts: 1571
Joined: Wed Mar 24, 2010 5:48 pm

Re: Encoder Basics

Post by cncsnw »

tblough wrote:lead and pitch are the same. ...
Pitch is how far a screw advances in one turn.
Just to be pedantic here:
- Lead is how far a screw advances in one turn.
- Pitch is the distance between successive thread crests.
- They are the same for a single-start thread (the vast majority of threads you will encounter).
- They are different for multi-start threads: lead = pitch * number of starts.
BigWillieStyle
Posts: 7
Joined: Wed Nov 29, 2017 7:26 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Encoder Basics

Post by BigWillieStyle »

Thanks tb, I appreciate the clarification. Also with regard to encoders, through some additional reading I found a diagram via Dynapar as being a helpful tool for those less familiar, like myself, to delineate the semantics of encoder classification.

http://www.dynapar.com/uploadedFiles/_S ... _29_13.pdf

Image

To the experts, please confirm or correct my assertation with regard to the correct encoder type.
Chaz
Posts: 381
Joined: Thu Feb 08, 2018 7:57 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Encoder Basics

Post by Chaz »

Is there any way to use an encoder that does not make the individual A- B- and Z- available but uses a common instead?

This is the specsheet.

https://docs-emea.rs-online.com/webdocs ... e8dd0d.pdf

Thanks
Chaz
Posts: 381
Joined: Thu Feb 08, 2018 7:57 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Encoder Basics

Post by Chaz »

Probably doesnt matter, it has too low res anyways to be any good it seems.
jmaks
Posts: 8
Joined: Sun Feb 18, 2018 4:11 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: Yes
CPU10 or CPU7: No
CNC Control System Serial Number: E8EB11292335-0206180631

Re: Encoder Basics

Post by jmaks »

Post Reply