Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
03/20/07 13:31
Read: times


 		 #135388 - another experiment
Responding to: ???'s previous message
Just now i was connected 30kg ,2mv/V ,loadcel to AD7730,
5VDC excitation, no digital filter performed in software..
I put over loadcell my phohe (about 110g). Difference between ADC results was about 3. So i have about 70..80 stable ADC units for 110 g on 30kg sensor.

Display is updated twice per second and i'm monitoring this display, no real conversion sample by sample.
Anyway lets calculate:
110/70=1.57->1.5g per stable ADC unit.
(1.5g / 30000g )*10mV = 0.5 microV.

What You have:
12 bits stable -> 4096 stable units.
15mV/4096 = 3.66 microV for stable ADC unit.
First check this "constant power supply".
Or try simple resistive divider, powered by reference voltage of ADC.
regards.




List of 80 messages in thread
TopicAuthorDate
Load Cell            01/01/70 00:00      
   24 bits            01/01/70 00:00      
   Load Cells            01/01/70 00:00      
      Alex            01/01/70 00:00      
         Alexandria library            01/01/70 00:00      
         All Wlcome in alex            01/01/70 00:00      
      opamp            01/01/70 00:00      
         re: opAmp            01/01/70 00:00      
            averaging how long? and noamp!            01/01/70 00:00      
            resume            01/01/70 00:00      
               resume opamps            01/01/70 00:00      
                  NO WAY            01/01/70 00:00      
               Already answered            01/01/70 00:00      
                  Really?            01/01/70 00:00      
                     Yes, really!            01/01/70 00:00      
                        not agree            01/01/70 00:00      
                           you are fully right            01/01/70 00:00      
                              why use opamp?            01/01/70 00:00      
                                 Too specific?            01/01/70 00:00      
                                    not too specific            01/01/70 00:00      
                           What the hell...            01/01/70 00:00      
                              nothing wrong, just old, dont be angry            01/01/70 00:00      
                                 But, what's wrong with "old"??            01/01/70 00:00      
                                    You should know that, Kai            01/01/70 00:00      
                                       shame for me,agree            01/01/70 00:00      
                                       How incredibly stupid to call a 1982's ...            01/01/70 00:00      
                                          were it only so well            01/01/70 00:00      
                                             You are sooo right...            01/01/70 00:00      
                                                Bob Pease            01/01/70 00:00      
                                                   I religously agree            01/01/70 00:00      
                                                   Pease = God?            01/01/70 00:00      
                                             I should add            01/01/70 00:00      
                                 AC Excitation            01/01/70 00:00      
                                    We Became 3 persons            01/01/70 00:00      
                                    AC excitation            01/01/70 00:00      
                                       100 nv ?            01/01/70 00:00      
                                       100 nv ?            01/01/70 00:00      
                                          100nV            01/01/70 00:00      
                                       Weighing lore            01/01/70 00:00      
                                          Looks exactly like VLF noise!            01/01/70 00:00      
                                             to: Kai Klaas            01/01/70 00:00      
                                                Lock-in uses AC excitation            01/01/70 00:00      
                                             AC Excitation            01/01/70 00:00      
                                                Artefacts            01/01/70 00:00      
                                          not 100nV            01/01/70 00:00      
                                             ADCs            01/01/70 00:00      
      probably?            01/01/70 00:00      
   Is "hysteresis" specified for your load cell?            01/01/70 00:00      
      Why dont you answer my question?            01/01/70 00:00      
         even nastier            01/01/70 00:00      
            Mechanical issues            01/01/70 00:00      
               Mech ?            01/01/70 00:00      
         i thought in that            01/01/70 00:00      
   to stefen and eric            01/01/70 00:00      
      And Load Cell type            01/01/70 00:00      
         send to me datasheet of loadcell            01/01/70 00:00      
   a load of stuff on loadcells            01/01/70 00:00      
   The Author            01/01/70 00:00      
      Variation            01/01/70 00:00      
         11bit from 24 bit            01/01/70 00:00      
         Davids answer woefully incomplete            01/01/70 00:00      
      "constant power supply of 15 mv" ???            01/01/70 00:00      
         kind of that power supply            01/01/70 00:00      
            bad experiment            01/01/70 00:00      
      another experiment            01/01/70 00:00      
         CS5532 comparison            01/01/70 00:00      
            30 kg to 3.5g is NOT 1:100,000 it is 1:8,000            01/01/70 00:00      
               yes and not            01/01/70 00:00      
               Erik            01/01/70 00:00      
                  David , what broadband he uses?            01/01/70 00:00      
                  there must be some misunderstanding here            01/01/70 00:00      
                     Simulator            01/01/70 00:00      
                        oh,            01/01/70 00:00      
      You misunderstood something!!            01/01/70 00:00      
         im sorry            01/01/70 00:00      
      Common mode input voltage range is violated!            01/01/70 00:00      
   Please modify your user profile,...            01/01/70 00:00      
      User profile            01/01/70 00:00      
         Haha...            01/01/70 00:00      
      ok I updated my profile            01/01/70 00:00      

Back to Subject List