OCCRA
Go to Post Any adult can open a door. Some can give direction. A few can give leadership. These are the true mentors. This is where true success comes from. - sanddrag [more]
Home
Go Back   Chief Delphi > Technical > Electrical
CD-Media  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 11-09-2018, 12:35 PM
HoracioJoe HoracioJoe is offline
Registered User
FRC #3620 (The Average Joes)
Team Role: Programmer
 
Join Date: Feb 2018
Rookie Year: 2017
Location: St. Joseph, MI
Posts: 5
HoracioJoe is an unknown quantity at this point
Can't get AMT absolute encoders to work

So we're doing swerve for our first time this year, and we bought a couple of AMT 112S encoders to measure the wheels' azimuth.

To test the encoder we 3D printed a gear with a long shaft which rotates on a bearing attached to the case. It can be seen here:



We used the cable seen on the picture, and based on the datasheet we marked down which wires are what and taped the ones we didn't need. We plugged in the wires to an Interface Board on top of a Talon SRX we have hooked up to a test board.

We use LED's on the board to see if we are getting encoder readings, but when we tried spinning the gear, the A and B LED's on the board didn't blink. We double checked several times that the wires matched the pins on the datasheet to make sure the wiring was done correctly. We swapped out encoders to see if it was the encoder that was faulty but we still didn't get any signal.

To test the individual pins (A and B) we made a small circuit with resistors, a power source and an oscilloscope that plugged into the encoder. We still wouldn't get any voltage oscillations for either pin when we spun the gear.

Does anyone have any experience with these encoders or has had a similar issue? Is there any obvious step that we missed? We are stuck at the moment and don't know what to do.

Any help is appreciated.

Thanks!
Reply With Quote
  #2   Spotlight this post!  
Unread 11-09-2018, 12:39 PM
Marcus Q Marcus Q is offline
Reversible bumpers are my trigger
AKA: Marcus Quintilian
FRC #5406 (Celt-X)
Team Role: Mechanical
 
Join Date: Mar 2012
Rookie Year: 2012
Location: Toronto
Posts: 1,611
Marcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond repute
Re: Can't get AMT absolute encoders to work

What did you set the PPR to?
__________________
2012-2015: 865 Warp7 Team Captain
2016/17: Free Agent Mentor
2018-present: 5406 Celt-X
Reply With Quote
  #3   Spotlight this post!  
Unread 11-09-2018, 12:40 PM
marshall's Avatar
marshall marshall is offline
"Who's Marshall?"
FRC #0900 (The Zebracorns)
Team Role: Mentor
 
Join Date: Jan 2012
Rookie Year: 2003
Location: North Carolina
Posts: 3,033
marshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond repute
Re: Can't get AMT absolute encoders to work

Quote:
Originally Posted by HoracioJoe View Post
So we're doing swerve for our first time this year, and we bought a couple of AMT 112S encoders to measure the wheels' azimuth.

To test the encoder we 3D printed a gear with a long shaft which rotates on a bearing attached to the case. It can be seen here:



We used the cable seen on the picture, and based on the datasheet we marked down which wires are what and taped the ones we didn't need. We plugged in the wires to an Interface Board on top of a Talon SRX we have hooked up to a test board.

We use LED's on the board to see if we are getting encoder readings, but when we tried spinning the gear, the A and B LED's on the board didn't blink. We double checked several times that the wires matched the pins on the datasheet to make sure the wiring was done correctly. We swapped out encoders to see if it was the encoder that was faulty but we still didn't get any signal.

To test the individual pins (A and B) we made a small circuit with resistors, a power source and an oscilloscope that plugged into the encoder. We still wouldn't get any voltage oscillations for either pin when we spun the gear.

Does anyone have any experience with these encoders or has had a similar issue? Is there any obvious step that we missed? We are stuck at the moment and don't know what to do.

Any help is appreciated.

Thanks!
I suspect it's this:

Quote:
Originally Posted by Datasheet
The AMT11 series encoder is designed to operate with a serial UART interface. This interface allows the encoder to be configured and programmed by the AMT ViewpointTM application. Along with programming, the AMT ViewpointTM application uses the serial interface for diagnostics and index alignment. Below are instructions on how to use the serial interface for position zeroing.
You'll likely need to configure it over serial before you can use it. I could be wrong because I haven't worked with these but this seems highly probable.
__________________
"La mejor salsa del mundo es la hambre" - Miguel de Cervantes
"The future is unwritten" - Joe Strummer
"Simplify, then add lightness" - Colin Chapman
Clarke's Laws
Reply With Quote
  #4   Spotlight this post!  
Unread 11-09-2018, 12:45 PM
HoracioJoe HoracioJoe is offline
Registered User
FRC #3620 (The Average Joes)
Team Role: Programmer
 
Join Date: Feb 2018
Rookie Year: 2017
Location: St. Joseph, MI
Posts: 5
HoracioJoe is an unknown quantity at this point
Re: Can't get AMT absolute encoders to work

Quote:
Originally Posted by marshall View Post
I suspect it's this:



You'll likely need to configure it over serial before you can use it. I could be wrong because I haven't worked with these but this seems highly probable.
Sorry, I forgot to mention we did configure it over serial before we used it, we made sure it had the latest firmware and configured it.
Reply With Quote
  #5   Spotlight this post!  
Unread 11-09-2018, 12:46 PM
HoracioJoe HoracioJoe is offline
Registered User
FRC #3620 (The Average Joes)
Team Role: Programmer
 
Join Date: Feb 2018
Rookie Year: 2017
Location: St. Joseph, MI
Posts: 5
HoracioJoe is an unknown quantity at this point
Re: Can't get AMT absolute encoders to work

Quote:
Originally Posted by Marcus Q View Post
What did you set the PPR to?
We set it to 4096 CPR, so I think that would be 1024 PPR
Reply With Quote
  #6   Spotlight this post!  
Unread 11-09-2018, 12:52 PM
marshall's Avatar
marshall marshall is offline
"Who's Marshall?"
FRC #0900 (The Zebracorns)
Team Role: Mentor
 
Join Date: Jan 2012
Rookie Year: 2003
Location: North Carolina
Posts: 3,033
marshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond reputemarshall has a reputation beyond repute
Re: Can't get AMT absolute encoders to work

Quote:
Originally Posted by HoracioJoe View Post
Sorry, I forgot to mention we did configure it over serial before we used it, we made sure it had the latest firmware and configured it.
Cool. Have you tried putting in an email or call to CUI and see if they can help with diagnosing the problem?
__________________
"La mejor salsa del mundo es la hambre" - Miguel de Cervantes
"The future is unwritten" - Joe Strummer
"Simplify, then add lightness" - Colin Chapman
Clarke's Laws
Reply With Quote
  #7   Spotlight this post!  
Unread 11-09-2018, 01:08 PM
HoracioJoe HoracioJoe is offline
Registered User
FRC #3620 (The Average Joes)
Team Role: Programmer
 
Join Date: Feb 2018
Rookie Year: 2017
Location: St. Joseph, MI
Posts: 5
HoracioJoe is an unknown quantity at this point
Re: Can't get AMT absolute encoders to work

Quote:
Originally Posted by marshall View Post
Cool. Have you tried putting in an email or call to CUI and see if they can help with diagnosing the problem?
Yea, I sent them an email the other day and I am still waiting for a response. I might give them a call when I get the chance.
Reply With Quote
  #8   Spotlight this post!  
Unread 11-09-2018, 01:12 PM
Marcus Q Marcus Q is offline
Reversible bumpers are my trigger
AKA: Marcus Quintilian
FRC #5406 (Celt-X)
Team Role: Mechanical
 
Join Date: Mar 2012
Rookie Year: 2012
Location: Toronto
Posts: 1,611
Marcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond reputeMarcus Q has a reputation beyond repute
Re: Can't get AMT absolute encoders to work

Is there a reason your using the AMT11 over the simpler AMT10's? I've used those successfully in the past. I'd assume you want the configurable index for your azimuth?

If your getting absolutely nothing on the oscilloscope I'd lean towards some sort of configuration issue.
__________________
2012-2015: 865 Warp7 Team Captain
2016/17: Free Agent Mentor
2018-present: 5406 Celt-X
Reply With Quote
  #9   Spotlight this post!  
Unread 11-09-2018, 02:09 PM
HoracioJoe HoracioJoe is offline
Registered User
FRC #3620 (The Average Joes)
Team Role: Programmer
 
Join Date: Feb 2018
Rookie Year: 2017
Location: St. Joseph, MI
Posts: 5
HoracioJoe is an unknown quantity at this point
Re: Can't get AMT absolute encoders to work

Yes, we went for it because we we want to use the index pulse.

I'll go over the configuration again to make sure its properly set up, thanks!
Reply With Quote
  #10   Spotlight this post!  
Unread 11-10-2018, 12:49 AM
asid61's Avatar
asid61 asid61 is offline
Design Simple
AKA: Anand Rajamani
FRC #1072 (Harker Robotics)
Team Role: Mentor
 
Join Date: Jan 2014
Rookie Year: 2013
Location: Cupertino, CA
Posts: 3,086
asid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond repute
Re: Can't get AMT absolute encoders to work

The AMT102/3 have index pulses, FWIW. I've used AMT103s several times without issue. Going forward, I would recommend them for simplicity's sake.
__________________
Team 1072 2017-present
Team 299 2017
Team 115 2013-2016 (student)

2018 Davis Finalists (w/ 6474 and 3880), 2018 Roebling Winners (w/ 3476, 1323, and 1778)

Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 12:22 AM.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin®
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi