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ADS1248 EVM Data Recorder Issues During 4 Wire RTD Measurement

Steven Bramsiepe
Prodigy 120 points
Other Parts Discussed in Thread: TUSB3410, ADCPRO, ADS1232

Hello again.

Thanks for any help that can be given however I previous posted about an error with gathering data. Its not coming up with any error but the data its saved is useless. I should note that i did a 1 hour test not using the data recorder and it looked ok.

I am doing a ratiometric measurement of a pt100 + a 10kOhm bias resistor as the reference. The settings on the software are:

PGA: 64
SPS: 5
AI0/1
Vref0
Internal reference on
IDAC 100uA @ IEXC1
Power Supply +-2.5V

The connections are on the IEXC1, AI0/1 the reference +- pins to the right of the analogue inputs. The final connection goes to the 2 AGND pins on the bottom right.

The problem here as well is that i can do a small sample test, say 10 samples and it looks fine. However I then tell it do a 18k samples and i dont get to see what the data looks like until it finishes. 

Any help that can be given to resolve this is much appreciated as we require knowing which device we want to use soon.

Steven

  • 0
    Prodigy 120 points
    I did another test over night and looked at the data. It seems to be working again however this has been an issue multiple times now and is a problem. Thanks for any help,
    Steven
  • 0 in reply to Steven Bramsiepe
    TI__Guru* 97465 points

    Steven,

    One other thing that might be an issue is the operating system. If you are using Windows 8 or higher, there might be problems that we haven't seen yet. At this point we're not really supporting that operating system, but there have been people who have been able to run it without problems.

    However, I want to follow up on a method that I mentioned in a previous post. Have you tried to run the EVM through a terminal program? It's rather simple and I've been able to take a large amount of data and send it to a text file. It may be a bit more complicated to set up the device, but you should be able to set it up, run it, and collect data rather easily.

    Since the EVM operates as a virtual COM port, you can send it basic commands and get data through a streaming mode.

    First you find the EVM on the com port. Here I've opened up the device manager and found the TUSB3410 device on COM3. The COM port will depend on your system and you'll need to open the device manager to find which port it is found on:



    I've gotten hyperterm (which I think I was able to get for free) and opened a new connection which I've called test. Then I connect to COM3.



    For communciations I set the baud rate to 230400, 8 data bits, no parity, 1 stop bit, and set the flow control to none.



    After that I can send commands to the EVM. Start with "q" which lists the setting of the device. I also set the data rate to the lowest setting and tie the inputs together on AIN0. "s" will start the stream of data and space bar will allow you to stop.


    Then I go to the Transfer tab and select Capture Text which will allow you to send anything coming over the line to a text file. There might be some issues with the fact that there is no flow control, but with lower data rates, I think it'll be unlikely that there will be a problem. When you're done, you can go back to the Transfer tab and stop the transfer. Additionally, the terminal program doesn't stop, so you can see the data as it comes up.

    Since this is a bare bones method of getting the data, it should have less of an issue with getting what you need. Regardless you should try this and see if it works. Was able to collect data within 10 minutes.



    Joseph Wu

  • 0 in reply to Joseph Wu
    TI__Guru* 97465 points
    Steven,


    One more thing, the console commands for the terminal can be found in this post with an attached pdf:

    e2e.ti.com/.../526705


    Joseph Wu
  • 0 in reply to Joseph Wu
    TI__Guru* 97465 points
    Steven,


    A colleague just reminded me that you could use ADCPro to set up the device in the configuration that you want. After that, you exit ADCPro and the EVM is left in that state. Then you could open up the terminal program and stream the data. This would probably save you a lot of time in the set up and getting data.


    Joseph Wu
  • 0 in reply to Joseph Wu
    TI__Prodigy 10 points

    Has anyone had success getting this EVM to work inside Labview?

  • 0 in reply to Byron Shulver
    TI__Guru* 97465 points

    Byron,


    The short answer is yes, it has been done before. You can setup an NI-VISA com channel and communicate to the device. The console commands are given in a one of the posts in this thread.


    Joseph Wu

  • 0 in reply to Joseph Wu
    TI__Guru* 97465 points
    Byron,


    Just for a complete answer for this post, something similar was done with the ADS1232 and was described in this post here:

    e2e.ti.com/.../479163


    Joseph Wu