AnsweredAssumed Answered

AD7606-6 conversion result

Question asked by deltanick on Mar 11, 2015
Latest reply on Mar 12, 2015 by deltanick

Dear All,

I'm using the board Eval-ad7606-6EDZ to acquire analog signal, this is connect with a dsPIC33 by using the serial interface.

I need an input range of +-5V.

 

 

This is the connection of the pin

SER/!PAR -> Vdrive

RANGE -> GND

REFSEL -> Vdrive

DoutA ->  dsPIC

CONVST -> dsPIC

SCLK -> dsPIC

!CS -> dsPIC

BUSY ->dsPIC

STBY -> Vdrive

OS0 -> GND

OS1 -> GND

OS2 -> GND

 

After power-up the dsPIC send a reset signal to the converter.

I have a problem with the conversion result. When the input voltage is larger than +-2.5V,  the most significant bit of the result goes high, thus the value change the sign. For example if the input is 3V, the conversion result is -2.

Moreover, I have try with the input range of +-10V, RANGE -> Vdrive. In this way the problem is when the input is larger than +-5V, thus the problem persist.  Whith the +-10V range I used 6553.6 as conversion factor.

Which is the possible problem?

 

Thank you for your consideration.

Best regards.

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