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multi cal system PGA309 software

yechun yao
Prodigy 110 points
Other Parts Discussed in Thread: PGA309, MULTI-CAL-SYSTEM, PGA309-HT

hi ti,

     could  you  give me  a new beta version of the Multi-Cal PGA309 software. i download oid version , but that one just sopport DMM 34401, thank  you !

  • 0
    TI__Mastermind 27715 points

    Hello Yao,

    You can download the installer for version 2.1 of the Multi-Cal PGA309 software here: http://bit.ly/1IE8amm

    If you prefer to use the source code, download it here: Multi_CAL_PGA309.zip

    Best regards,

    Ian Williams
    Linear Applications Engineer
    Precision Analog - Op Amps

  • 0 in reply to Ian Williams
    Prodigy 105 points
    Hello Ian,

    The link that you provided for version 2.1 of the software doesn't seem to be working for me. Can you re-post it/update the link?

    Thanks,
    Greg
  • 0 in reply to Greg Harrington
    TI__Mastermind 27715 points

    Hello Greg,

    Sorry about that. Please try the link below:

    Best regards,

    Ian Williams

  • 0 in reply to Ian Williams
    Prodigy 105 points

    Thank you Ian, I was able to download it and install it. I'll be testing the setup later this week.

    Regards,

    Greg

  • 0 in reply to Ian Williams
    Prodigy 105 points
    Hello Ian,

    I was able to calibrate a pressure sensor with the PGA309 with an output of 2.5V to 4.5V.

    However, I wasn't able to successfully do the calibration with a secondary amplifier attached to the output of the PGA309. The secondary amplifier has a gain of 2.5 and an offset of -2.5V. This corresponds to an output of 0V to 5V out of the secondary amplifier and if you back calculate the output for the PGA309 is 2.5V to 4.5V.

    I checked the box for the secondary amplifier and put 2.5 in the gain box and -2.5 in the offset box. In the output target boxes I put 5 for the max target and 0 for the low target box.

    The secondary amplifier design works; I connected it to the PGA309 after I did the calibration for 2.5V to 4.5V and got the correct output of 0V to 5V.

    However, I'd like to calibrate the full 0-5V output through temperature to compensate for any temperature errors that the secondary amplifier introduces.

    Am I doing something wrong, or is this a bug in the multi-cal-system software?

    Thanks,
    Greg
  • 0 in reply to Greg Harrington
    TI__Mastermind 27715 points

    Hello Greg,

    I believe you have an error in your gain and offset calculation. With input (x) of 2.5V to 4.5V, gain (m) = 2.5, and offset (b) = -2.5, the output (y) is as follows:

    y = m*x + b
    y = 2.5*(2.5V, 4.5V) - 2.5V
    y = (6.25V, 11.25V) - 2.5V
    y = 3.75V, 8.75V

    You instead need a gain of 2.5 and an offset of -6.25V. If your secondary amplifier is working as you say, then it shouldn't need adjustment. Simply adjust your offset to -6.25 in the pre-cal file and try a new calibration.

    Best regards,

    Ian Williams

  • 0 in reply to Ian Williams
    Prodigy 105 points
    Thanks Ian, that worked!

    I was assuming that the order of operations in the software was the same as my secondary amplifier. On my amplifier I'm subtracting the 2.5V right away for a 0-2V signal, then gain that up by 2.5 for a 0-5V signal. Since I only have +/-8V rails on the secondary amplifier, I didn't even think to apply the gain first then subtract out the resulting 6.25V offset.

    Thanks,
    Greg
  • 0 in reply to Greg Harrington
    TI__Mastermind 27715 points

    Hi Greg,

    Glad that it worked!

    Best regards,

    Ian Williams

  • 0 in reply to Ian Williams
    Prodigy 105 points

    Hi Ian,

    When I run the multi-cal software and use 1 to 7 temperature points everything works great, however when I try to do 8 temperature points it seems like the eeprom doesn't get written correctly.

    I also noticed on the tab labeled OVER TEMPERATURE RESULTS only has 7 visible temperature points for each sensor, even though I have run 8 temperature points.

    Is this a bug?

    All of the cal data is written to a .xls spreadsheet, but I can't figure out how to import that into the multi-cal software so that I can try to re-write the data.

    Do you have any suggestions?

    Thanks,

    Greg

  • 0 in reply to Greg Harrington
    TI__Mastermind 27715 points
    Hi Greg,

    This may be a bug - I'll look into it. Just so I'm clear, you're calibrating at 8 discrete temperatures? Have you seen a performance increase by doing this? Typically we see no significant improvements after three temperature points.

    Best regards,

    Ian Williams
  • 0 in reply to Ian Williams
    Prodigy 105 points

    Hi Ian,

    Yes, we are trying to build the table with 8 discrete temperatures.

    We are using the PGA309-HT from -65F to +176F, with this wide temperature band we do see a performance increase with more temperature points.

    Thanks.

    Greg

  • 0 in reply to Greg Harrington
    TI__Mastermind 27715 points
    Hi Greg,

    I see. You are then using the internal temp ADC mode, and your bridge sensor is located near your PGA309?

    Best,

    Ian
  • 0 in reply to Ian Williams
    Prodigy 105 points

    Hi Ian,

    Yes, the bridge sensor is located close enough to the PGA309 that the PGA309 and associated components see the full temperature.

    We have experimented and successfully used both the internal temperature mode as well as an external temperature sensor in external mode; both giving similar results as far as the temperature compensation of the amplified output.

    I was experimenting to see if more than 7 temperature data points would give us better results when I ran into this issue with the 8 temperature data points.

    Thanks,

    Greg