ADS1259EVM-PDK Error code 5055

Hi Tao,

I'm very sorry to hear that you spent so much time waiting only to have ADCPro and the ADS1259EVM-PDK software throw an error.  I'll have Greg and Kevin look at this on Monday morning and see if they can provide you a reason/solution for/to this error code.

Hi Tom,

Thank you very much for looking into this issue. To better assist you and your coworkers, I have tried a couple of scenarios. Here is what I find out:

Case 1: If I keep the block size as 983340 and change the sample rate to 400SPS, the data acquisition will take about 0.68 hour (983340/400/3600=0.68), and I can get the output voltages without problems.

Case 2: If I change the block size to 483340 and change the sample rate to 60SPS, the data acquisition will take about 2.24 hours (483340/60/3600=2.24), and I will get the error code 5055.

Case 3: If I change the block size to 243340 and keep the sample rate as 60SPS, the data acquisition will take about 1.13 hours (243340/60/3600=1.13), and I will get the error code 5055.

Case 4: If I change the block size to 203340 and keep the sample rate as 60SPS, the data acquisition will take about 0.94 hour (203340/60/3600=0.94), and I can get the output voltages without problems.

Case 5: If I keep the block size as 203340 and change the sample rate to 50SPS, the data acquisition will take about 1.13 hour (203340/50/3600=1.13), and I will get the error code 5055.

From these cases, it seems that there is a 1-hour acquisition time limit either in the ADCPro or ADS1259EVM-PDK software. If the acquisition time exceeds 1 hour, the software throws out error code 5055; otherwise, it will give the acquired data. In the ADCPro user manual, I did not see an acquisition time limit. The only limitation is the block size, where its maximum is 1,048,576 samples per channel.

I hope my findings will help.

Thanks,

Tao

Tao -

Thank you for the experiments you performed.  It indeed appears that their may be something that happens around the 1 hour period that causes problems. We have not noticed this behavior before, so we will have to investigate this further.

Hi, 

   I meet the same problem. Is there any solution for this problem now?

  Thanks a lot!

Hi You Li,

I'm not aware of any solutions to this problem...

What settings were you using when you ran into this issue?

Best Regards,
Chris

When I set the sampling rate is 16.7 Hz and to record 57000 samples.

Hi You Li,

I don't think the number of samples is the issue; the problem seems to be related to collecting data over a long period of time. Are you trying to perform a long-term test with the EVM?

Unfortunately, right now we are not planning to provide a fix for this issue.

Best Regards,
Chris

Hi, Chris,

      Yes, it is a long-time sampling and the sampling time is about  one hour. I also tried half hour sampling time at sampling rate =16.7 or 15Hz. However, they also gave me Error code 5055.  I am not sure what I can do about this issue. Just avoid low sampling rate and long sampling time?

Hi You Li,

The low-sampling rate shouldn't be an issue, so long as you also select a smaller block size...

You could try using the "Data Recorder" function in ADCPro to collect a series of shorter sample periods. If you enable the "Auto" increment function and collect a smaller block size data using "Continuous" acquisition mode, you'll get several text files which you can combine into a longer data record. Note that the data might not be perfectly contiguous (you might miss some samples between data files), but if that doesn't matter to you then perhaps this would be a potential workaround to this limitation.

Best Regards,
Chris

Hi, Chris,

      I tried use the "Continuous" acquisition mode and save the data. I know there may be some samples are not captured. However, I assumed if my signal ( which is generated by my testing DAC) is very slow, then the time for data files switching is not important. 

      So my DAC is running at 0.8 Hz and the EVM sampling rate is 60Hz.  But I got a big problem, I found there are offset between samplings of different data files.  For example, as I show in the following figure, there is about 500 LSB jump between two different data files. At that jump point, the testing DAC's output is not changed.  I found it is always a about 500 LSB move up between different data files.  Could you please give me solution?

      Thanks a lot!

    

Hi You Li,

I'm not sure why the offset would change like that...

Are you sure that the change is offset occurring between data files and not within a single data file?

What kind of signal are you supplying from the DAC, and how is connected to the ADC inputs?
...When I test a DC input, I don't see a shift in the offset between "continuous" conversions.

What are you using for the "block size" in ADCPro?

Best Regards,
Chris

yes, the offset is occurring between data files.


The DAC is a 20 bit DAC and its supply voltage is 3.3 V. It provides square wave shape signal.

For example, the DAC 's input code are as
10000000000000000000001
10000001000000000000001
10000000000000000000010
10000001000000000000010
10000000000000000000011
10000001000000000000011
...


Its output is connected to the PGA input of the EVM (J8.3 and J8.4).

I choose the sampling rate is 60 SPS and block size is 18000

Hi You Li,

It's possible that something could be changing between conversions, since the ADC may be stopping and starting conversions. This can cause some transient effects.

What do you use for the DAC's reference voltage?

Also, have you tried enabling the the PGA280's current buffers?

Best Regards,
Chris

My DAC's reference voltage is generated by LTC6655 reference

How to enable the PGA280's current buffers? Will it help?

Thanks a lot!

Hi You Li,

ADCPro might give you the option to enable these buffers on the "PGA - Input Switch" tab. I don't have access to an ADS1259EVM at the moment, so I'm not able to try it out. These buffers are suppose to help with transients that may occur, say when switching an input MUX.

Does the offset you see ever settle back down to it's previous level or is it a permanent change?

This offset could also be a gain error due to a shift in the reference voltage. Are you able to try using the REF5025 from the ADS1259EVM as the reference for your DAC? If the DAC and ADC were to share the same reference, any change in reference voltage would cause a similar error to both the DAC and ADC, which would tend to cancel out the observed error.

Best Regards,
Chris