Gain doesn't work as expected

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Chris Holt

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Jan 21, 2014, 3:11:04 PM1/21/14
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The CEE is starting to work well for my application and I am pretty excited about learning more about it. 

I would like to increase the gain to improve the aliasing of my measured small voltage.  When i increase the gain to 2x the measured voltage drops by half on the pixelpulse readout and not much changes.  when I set it to 4x the measured voltage drops by 1/4.  It seems that the software is compensating but the device isnt implementing the expected gain.  What can I try to fix this?  

Thank you for your help.

Chris

Ian Daniher

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Jan 21, 2014, 3:18:01 PM1/21/14
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Hi Chris,

Sorry to hear you're having trouble! Can you share the information at http://apps.nonolithlabs.com/edge/debuginfo?

When a gain is selected, the full scale voltage will reduce to 5v/gain, as shown at http://i.imgur.com/rPiOYFP.png. From your description, it sounds like the full scale voltage isn't being modified? Can you take a screenshot of pixelpulse demonstrating the erroneous behavior?

Thanks!
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Ian
on behalf of Kevin & Nonolith Labs


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Chris Holt

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Jan 21, 2014, 6:45:09 PM1/21/14
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I am pulsing 190mA as the source and am measuring the heating of a fine wire that is approximately 1-2 ohm in resistance.  when the wire heats the resistance rises slightly and I want to see this.  In these screen shots I am starting with 1x and changing the gain to 2X and 4x.  the amplitude of the responding voltage decreases when i change the gain. 
Slide2.JPG
Slide3.JPG
Slide4.JPG
Slide1.JPG

Chris Holt

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Jan 21, 2014, 7:03:28 PM1/21/14
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This is the debug information

Nonolith Connect

Version: 1.3

Platform: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/32.0.1700.41 Safari/537.36

CEE

hwVersion: 1.0

fwVersion: 1.3a/ebdffb2a2848da1d*

serial: 239533834393FFFF40FFA0001200

EEPROM data:

Status 64
00: ee 6c e2 90 03 fc 04 fe
08: 16 07 f4 06 6f 06 56 06
10: ff ff ff ff ff ff ff ff
18: ff ff ff ff ff ff ff ff
20: ff ff ff ff ff ff ff ff
28: ff ff ff ff ff ff ff ff
30: ff ff ff ff ff ff ff ff
38: ff ff ff ff ff ff ff ff

Kevin Mehall

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Jan 22, 2014, 9:46:02 AM1/22/14
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Hi Chris,

Can you try reflashing your CEE's firmware?
http://apps.nonolithlabs.com/fwupdate?image=cee_1.0/fw_1.2.json

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Kevin Mehall
Nonolith Labs


Chris Holt

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Jan 22, 2014, 4:21:24 PM1/22/14
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I tried the re-flash but it seems to be doing the same thing.
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