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AD719X Reference Detect Not Working

Question asked by olso4539 on Sep 24, 2012
Latest reply on Oct 12, 2012 by MaryMc

I recently ran into a problem with the reference detect on the AD7193.  Reference Detect is not working properly on Ch3 only.  I posted one sample of hex output from 4 independent AD7193s on the same pcb.  All channels are open circuit reference.

 

As you can see from the status append on channel 3 (43 = error + ch3) the ADC recognizes there is an error, but does not reliably set the data all high nor does it set the NOREF bit (63 = error + noref + ch3).  Is there something special about Ch3?  Is there something else i might have set wrong?

 

 

Register Settings

 

ADC110030F5781C2100
ADC210030F578142100
ADC310030F578142100
ADC410030F578142100

 

 

I just tried something new.  When the temperature sensor is turned off, the reference detect works on Ch3.  Any ideas why the temperature sensor might interfere with the reference detect only on ch3?

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