questions about ADIS16265 and EVAL-ADIS

Thank you for your post! You do not need to apologize for answering questions. If you have them, there is a great chance that someone else has similar questions as well, so we appreciate you taking the time to post your questions in this forum. For simplicity, we do try to focus on one question per discussion, but I will break your questions out into separate comments.  If you have follow-up questions, can you copy and past the question and comments associated with that particular topic, into your response, so we can keep this clear?  Thank you! Let's get started!  

Question #1

In refrence to 13 page of ADIS16265 datasheet, when SMPL-PRD[7:0]=0x00, the internal sample rate is 2048 SPS. While we have tested the ADIS16265 with EVAL-ADIS but the maximum sample rate has been equaled to 512 SPS. Why this happened?

NevadaMark>> I haven't tested this particular product in a while, so I will need to set this up and try this myself.  The 2048SPS sample rate setting is fairly unique, when compared with the rest of our products, so perhaps you have found a bug that needs to be addressed. I am not sure how quickly our software resource will be available to confirm this, so please give me 2-3 business days to provide an update on this one. 

Question #2

We have a problem with EVAL-ADIS software. with respect to the data ready synchronization has been enabled (in data capture menu -->data log advanced options) Nevertheless over sample data records(for example: in data records option-->length record =1000, we expected the data records would be equal to 1000 while the data records which have been observed are equal to 1200). What is the reason of what happened?

NevadaMark>> Is this really a problem?  This relates to the structure of the data communications between EVAL-ADIS and the PC.  We had a choice to throw out the extra data or provide it in the output file.  We chose to give you, the customer, that choice.  You can eliminate that the data from your record if this is a problem.  Will that work OK for you?

Question #3

What leads to create the error of: "AdisApi transfer timedout" when the data capture is failed.

NevadaMark>> That typically comes from a loss of the data ready signal, somewhere between the ADIS16265 and the processor on the EVAL-ADIS board. 

Question #4

I couldn’t have understanded the relative between sclk frequency(in tool menu--> SPI) and sample rate (it sets by SMPL-PRD[7:0])to access the corect data capture. for example(for ADIS16266) in sample rate 2429 SPS, the repititive data have been observed mostly. While in sample rate 151 SPS, data variation is high. would you consider the relative between slck frequency and sample rate?

NevadaMark>> The SCLK frequency describes the rate at which the processor (on the EVAL-ADIS) transfers each bit from the ADIS16265.  The sample rate describe the rate at which the output data registers (in the ADIS16265 or ADIS16266) are updated.  In essence, they are unrelated.  The SCLK rate influences how fast the evaluation board can collect data, but it DOES NOT influence the sample rate inside of the ADIS16265.  They are two completely different things. With respect to this part of your question, you might want to start a separate discussion thread, where you quantify the variation you are seeing so we can clearly understand what you are observing and what your question is.  Within this context, I fear that discussion could be too complex would create confusion.  Will that work OK for you?  Happy to help, but I do want to make sure this is clear for you and for any future visitors to this forum.  Thank you!

Question #5

What is your suggestion about the gyro test in dynamic with EVAL-ADIS? What I mean is the EVAL-ADIS would be on the rate table and 4 lines of usb transfered with slipring (there is inside rate table) or EVAL-ADIS would be outside of rate table and 16 lines of gyro (for example ADIS16266) transferred with slipring?

NevadaMark>> Can you post this question in a separate discussion?  I suspect that this could require some dialog, which is different from the rest of these questions. Thank you!

Thank you for spending time, okay, I will copy and paste every question in seprated post. Your soon response would be highly appreciated

Very truly yours

The extra data is no problem but I feel my data capture is incorrect that leads to this problem.with respectto the "disabling DR sync. Will cause over sampled or under sampled data records" I think if the data ready synchronization enable, the records data length should be equal to the same which is determined in data records option-->length record.

Am I right?

Thank you so much for your detailed explanation, I got it, but what is the reason of what I've observed "in sample rate 2429 SPS, the repititive data have been observed mostly. While in sample rate 151 SPS, data variation is high"?

Question #2

We have a problem with EVAL-ADIS software. with respect to the data ready synchronization has been enabled (in data capture menu -->data log advanced options) Nevertheless over sample data records(for example: in data records option-->length record =1000, we expected the data records would be equal to 1000 while the data records which have been observed are equal to 1200). What is the reason of what happened?

NevadaMark>> Is this really a problem?  This relates to the structure of the data communications between EVAL-ADIS and the PC.  We had a choice to throw out the extra data or provide it in the output file.  We chose to give you, the customer, that choice.  You can eliminate that the data from your record if this is a problem.  Will that work OK for you?

NevadaMark>> This seems a bit different from the original question, but happy to help.  Is there a reason you would not want to synchronize this with data ready?  If you do not use data ready, the IMU Evaluation Software provides no opportunity for controlling the data update rates....so yes, you could over-sample or under-sample.