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-   -   Accelerometer Example of New Crio (http://www.chiefdelphi.com/forums/showthread.php?t=99772)

Joe Ross 20-01-2012 16:44
Re: Accelerometer Example of New Crio
 
Quote:
Originally Posted by jhersh (Post 1109875)
Not sure what "flat cable" you are talking about. If it is the DB-37 cable from the kit, then it "only works" if you fix the cable end to not be reversed.
Several people have reported it worked with the fixed cable in this year's kit, but not the DB37 from a previous year's kit.

Looking through previous year's KOP lists, it looks like there have been several sources. In 2009 and 2010, it was a cablestogo pn 02688. Last year it was SF Cable pn D720-03. Maybe one of these was missing a pin that related to I2C.

zlong 22-01-2012 14:00
Re: Accelerometer Example of New Crio
 
We also struggled with the ADXL345 in I2C mode. Running the included LabVIEW example the device worked intermittently. I looked at SDA and SCL with an O-Scope and noticed they where kind of floating when communication had error-ed out. My fix for this was to place a 100 ohm pull up resistor on both SDA and SCL. This made the ADXL345 perform wonderfully on the I2C bus. We have implemented this fix on our robot and so far have been very happy with the ADXL345's performance.

Joe Ross 22-01-2012 14:22
Re: Accelerometer Example of New Crio
 
Quote:
Originally Posted by zlong (Post 1111200)
We also struggled with the ADXL345 in I2C mode. Running the included LabVIEW example the device worked intermittently. I looked at SDA and SCL with an O-Scope and noticed they where kind of floating when communication had error-ed out. My fix for this was to place a 100 ohm pull up resistor on both SDA and SCL. This made the ADXL345 perform wonderfully on the I2C bus. We have implemented this fix on our robot and so far have been very happy with the ADXL345's performance.
100 ohms seems like a lot for I2C to me. The [url=http://www.usfirst.org/sites/default/files/uploadedFiles/Robotics_Programs/FRC/Game_and_Season__Info/2012_Assets/Digital%20Sidecar.pdf]Digital Sidecar is supposed to have 3.16k on SDA and SCL. Can you check if those pullups are working?

Doug Norman 23-01-2012 09:15
Re: Accelerometer Example of New Crio
 
Quote:
Originally Posted by billbo911 (Post 1102599)
We can figure out how to run the I2C ADXL345 example, but where we are struggling is how to go about integrating the vi's into our robot project.

Can someone please point us in the right direction to help us figure out how to add support for the ADXL345 via I2C to our project?
You might take a look at the tutorial. From the LabVIEW Getting Started Window, click Tutorials, and then choose Tutorial 7 - Integrating Examples into Robot Code.

billbo911 23-01-2012 09:37
Re: Accelerometer Example of New Crio
 
Quote:
Originally Posted by Doug Norman (Post 1111766)
You might take a look at the tutorial. From the LabVIEW Getting Started Window, click Tutorials, and then choose Tutorial 7 - Integrating Examples into Robot Code.
Thanks Doug, I'll have our programmers do this today.
I believe I have a handle on it now, but I want them to understand the process. So, between the tutorial and my experience, we should be if fine shape!

Gary Bonner 26-01-2012 00:35
Re: Accelerometer Example of New Crio
 
1 Attachment(s)
My Labview Getting Started window does not list any tutorials. Can they be found anywhere else?

Alan Anderson 26-01-2012 01:06
Re: Accelerometer Example of New Crio
 
Quote:
Originally Posted by Gary Bonner (Post 1113725)
My Labview Getting Started window does not list any tutorials.
It looks like you might not have installed the NI LabVIEW update linked from the Kit of Parts page.

rwood359 26-01-2012 01:12
Re: Accelerometer Example of New Crio
 
Quote:
Originally Posted by jhersh (Post 1109879)
It works with my thick round one. Maybe yours is just damaged.

-Joe
We couldn't communicate on the I2C bus using the round cable. Switching to the flat cable fixed the problem.

jhersh 26-01-2012 15:21
Re: Accelerometer Example of New Crio
 
Quote:
Originally Posted by rwood359 (Post 1113738)
We couldn't communicate on the I2C bus using the round cable. Switching to the flat cable fixed the problem.
Good to know. Seems like there must have been a bad set of cables one of the previous years. I'm a little surprised that teams didn't complain about this in the year the bad cables were included. I guess no team tried to use I2C in that year. Given that this is the first year with a challenge that benefits from an accelerometer, I guess that makes sense.

-Joe


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