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AD7730 incomming Data

Question asked by AhmedAwad on Apr 5, 2016
Latest reply on Apr 12, 2016 by AhmedAwad

Dear Sir...

 

Iam working on weigher design for 15 Kg range, i can read from internal register of AD7730,

I configured in bipolar mode, HIREF 1 (5V), Range +_20mV 24bit.

 

The result of calibration Internal Full scale calibration = 0x593CEA

                                       Internal Zero Scale Cal          = 0x800000

 

I have two problems as follows :

1. if i configure the chip for uni-polar mode the output becomes zeros !!!!!!

2. If i configured for bipolar mode it give me the following result :-

 

--4/5/2016 19:42:41 [RX] - 59 3C EA 80 00 00  ( Internal Full and Zero Calibration)

--4/5/2016 19:42:41 [RX] - EB B9 A7 E5 FF FF FF FF FF FF FF FE FF F8 5F FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ------ 11  (24 bit bytes)

 

91 80 80 01 01 23 02 46 02 8C 04 04 08 09 18 12 30 10 60 20 24 40 48 C0          8  (24 bit bytes)

91 80 80 01 01 23 02 46 02 8C 04 04 08 09 18 12 30 10 60 20 24 40 48 C0

91 80 80 01 01 23 02 46 02 8C 04 04 08 09 18 12 30 10 60 20 24 40 48 C0

91 80 80 01 01 23 02 46 02 8C 04 04 08 09 18 12 30 10 60 20 24 40 48 C0

91 80 80 01 01 23 02 46 02 8C 04 04 08 09 18 12 30 10 60 20 24 40 48 C0

91 80 80 01 01 23 02 46 02 8C 04 04 08 09 18 12 30 10 60 20 24 40 48 C0

 

As you see in first line the result of full and zero calibration as in the data sheet now the coming data from AD7730 is strange but after the first 11 bytes  there are 8 bytes repeated the same even if i disconnect the Load cell.

 

Any Advice....

Ahmed

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