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ADIS16365 interface with dsPIC

Hi everyone , it's the first time to me here.. i have a strange problem ..

i am working on ADIS16365 interface with dsPIC , I wrote a code to extract all these data :

1- Power supply measurement

2- x,y,z gyroscope output

3-  x,y,z accelerometer output

4 - x,y,z gyroscope temperature output

i read all these data correctly except accelerometer y output , it gave a strange output

i used the same methods and calculations with accelerometer x and z and there wasn't any problem , i didn't use burst mode to extract these data ,  i send a command every time

for example , i used  this part of code to read accelerometer x :

         SPI2_Write(0x0A00);                        // Send data via SPI


          XGValue = SPI2_Read(buffer);              // Read the MSByte

          info[4] = (XGValue & 0b0011111111111111); //Strip off the ND and EA flags

so, any help ?

  • We will be glad to help.  What is strange about the data you are observing in the y-axis accelerometer data?  What are they other sensors reading?  What orientation is the device in while you are measuring this?  In other words, what should we expect if it were operating normally?  Thanks! We appreciate your post and look forward to your response. 

  • Thanks for your response .. actually , all other sensors reading are perfect , accelerometer x is almost 0 , accelerometer z is -1 approximately , gyros are almost 0 and their values changes logically with ADIS16365  movement , supply voltage is 5 volt and temperature readings are perfect .

    during these readings , i put ADIS16365 IMU  on a table  , so , i expected some offset value , but the problem was here :

    accelerometer y readings came like this :





    all these strange readings are coming without any change in ADIS16365  position ,  i replaced this IMU by a new one but the problem was same , so , could you please suggest any solution for this strange problem ?

    it looks like the address of accelerometer y  is not 0x0C , but i checked it in the datasheet and it is 0x0C

    so, any help ?

  • What units are you associating with these numbers?

  • G is the unit  .. so , for example , if we take -4.63620 as an output , that means acceleration y = -4.63620 * 9.8 = -45.43476 .. so, it is a strange output 

  • I agree with you; that is well outside of normal expectation.  Do you have anything connected to pins 22, 23 or 24? 

  • Sorry for late .. I checked these pins and nothing connected .. I used SA16375 IMU breakout board and I remove the jumper that connected to pin 23 .. so , nothing connected to these pins ..

  • Thank you for sharing this! To be honest, I am stumped.  Pins 22, 23 and 24 offer access to the analog portion of each accelerometer's signal chain.  This had utility in an early application, but when we discovered that it was so easy to introduce undesirable influence, we decided to make these pins into "no connect" lines. Since you have two units, which are doing the exactly the same thing, on the same axis, while the rest of the device continues to work well, it is hard to imagine this as some sort of random failure event.  Is there any chance the units were subjected to any handling or application shock that is beyond the rated levels in the datasheet?  I am not sure what else to look at, but if you are convinced that you are doing everything correctly in the digital signal processing portion of your system, we do have a failure analysis service, which you can request, through your original point of sale.  Since that group does not use this forum for their inputs, you will want to provided a clear summary of your observations, methods and data (with annotations to make highlights easy to find).  When our F/A team has little or no description of the behavior, they are very limited in what they can do.  You can reference this discussion, but it would help to make sure that a link to this discussion is included in the F/A request form.   

  • This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

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    EZ Admin