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???
04/16/08 00:22
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#153416 - ground planes
Responding to: ???'s previous message
Mahmood Elnasser said:
I built a load cell board with LCD based on the AD7730 DIP package and I got satisfying results from first board using anlog and digital solid ground planes meeting in one point under the AD7730, with some minor drift proplems.


There's no need to have separate analog and digital ground planes, in spite of what most ADC and DAC data sheets tell you. Consider a system with more than one ADC. Where do you connect the ground planes together?

Simply pour one plane, and pay attention to your signal routing. Keep digital and analog signal traces as far away from each other as possible, and avoid allowing them to cross.

Where do you connect the shield? do you leave it open or do you connect it to both analog inputs with balancing resistors?


A shield is an extension of the chassis, and as such should be connected to the enclosure. Then make sure your enclosure connects to the circuit common.

-a


List of 36 messages in thread
TopicAuthorDate
Load cell shield            01/01/70 00:00      
   Earth ground            01/01/70 00:00      
      where is Earth ground ...            01/01/70 00:00      
         yes but..            01/01/70 00:00      
            Why Ain- is grounded...            01/01/70 00:00      
               read datasheet of AD7730            01/01/70 00:00      
                  it's correct            01/01/70 00:00      
            try Yourself and tell us result            01/01/70 00:00      
            Connect the shield to analog ground!            01/01/70 00:00      
               I tend to forget            01/01/70 00:00      
                  Good idea!            01/01/70 00:00      
                     Analog gnd            01/01/70 00:00      
                        Exactly!            01/01/70 00:00      
                           Ferrite beads trick!            01/01/70 00:00      
                     Loadcell Shield            01/01/70 00:00      
   ground planes            01/01/70 00:00      
      Hhm...            01/01/70 00:00      
         re: hmm            01/01/70 00:00      
            interesting            01/01/70 00:00      
               RF            01/01/70 00:00      
               RF GSM            01/01/70 00:00      
                  I use use this            01/01/70 00:00      
                  Walkie talkies            01/01/70 00:00      
               Load Cell Screens            01/01/70 00:00      
                  JUST FOR RECORD            01/01/70 00:00      
                  Two enclosures, on safety class I requirements            01/01/70 00:00      
            No proof, of course...            01/01/70 00:00      
   Load cell cable problem            01/01/70 00:00      
      fix it            01/01/70 00:00      
         Problem is            01/01/70 00:00      
            so make Digital Load Cell            01/01/70 00:00      
               good idea            01/01/70 00:00      
                  give picture            01/01/70 00:00      
            Screens and cables.            01/01/70 00:00      
               "Fixed Structure"            01/01/70 00:00      
                  Fixed?            01/01/70 00:00      

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