CR4 - The Engineer's Place for News and Discussion®

Previous in Forum: Bently Neveda Power Supply and Ribbon Damage   Next in Forum: Oven Automation
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







4 comments
Active Contributor

Join Date: Oct 2010
Posts: 14

Encoder

04/17/2012 4:19 AM

which type of Input card are uses in PLC system for Absolute & Incremental Encoder connection.

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 8461
Good Answers: 361
#1

Re: Encoder

04/17/2012 6:52 AM

Absolute: Digital Input (with as many inputs as the number of bits in the encoder output). You may find a dedicated encoder card, or you may need to convert the encoder output code (probably Gray code) to binary.

Incremental: Quadrature up/down counter for A and B (you can implement this with 2 digital inputs and some ladder logic for low speeds). You may or may not want to include the Z input - many quadrature counters in PLCs have provision for Z.

__________________
"Love justice, you who rule the world" - Dante Alighieri
Register to Reply
Active Contributor

Join Date: Oct 2010
Posts: 14
#3
In reply to #1

Re: Encoder

04/17/2012 1:07 PM

How Digital Input card gives us the rotation angle when we uses absolute encoder?

Register to Reply
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 8461
Good Answers: 361
#4
In reply to #3

Re: Encoder

04/17/2012 6:19 PM

Example:

Assume the encoder has 4 bits of resolution - the digital inputs (possibly after converting the code) will give a number between 0 and 15.

0 then represents 0°, and each other number represents (the number x (360/16))°.

So if the number was 8, for example, the shaft angle would be (8 * (360 / 16))° = 180°. OK?

Here's a table which may explain it better:

Input 3Input 2Input 1Input 0Gray CodeBinary Code Decimal NumberAngle
00000000000000.0
000100010001122.5
001100110010245.0
001000100011367.5
011001100100490.0
0111011101015112.5
0101010101106135.0
0100010001117157.5
1100110010008180.0
1101110110019202.5
11111111101010225.0
11101110101111247.5
10101010110012270.0
10111011110113292.5
10011001111014315.0
10001000111115337.5
__________________
"Love justice, you who rule the world" - Dante Alighieri
Register to Reply Score 1 for Good Answer
Guru
Popular Science - Cosmology - New Member Technical Fields - Technical Writing - New Member Engineering Fields - Energy Engineering - New Member Engineering Fields - Electrical Engineering - New Member Engineering Fields - Control Engineering - New Member Engineering Fields - Electromechanical Engineering - Old Member, New Association

Join Date: Apr 2008
Location: Lexington, KY
Posts: 1038
Good Answers: 56
#2

Re: Encoder

04/17/2012 12:26 PM

It may depend on the brand or manufacturer of the PLC you want to use.

Beckhoff Automation uses an EL5151 card as a dedicated encoder interface. Allen Bradley uses a couple of types depending on the model of controller you want to use.

High speed counters will frequently be used with a separate input for reseting to zero.

Happy Hunting!

__________________
A great troubleshooting tip...."When you eliminate the impossible, whatever remains, however improbable, must be the truth." Sir Arthur Conan Doyle
Register to Reply
Register to Reply 4 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Deepak.9 (1); JohnDG (2); NotUrOrdinaryJoe (1)

Previous in Forum: Bently Neveda Power Supply and Ribbon Damage   Next in Forum: Oven Automation

Advertisement