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ADS1232REF: Calibration weight is stuck negative

Chris Owens
Prodigy 40 points
Part Number: ADS1232REF
Other Parts Discussed in Thread: ADS1232

I was told to post here by Renan Adriano from TI Customer Support.

The calibration value is stuck negative which causes all mass measurements to be incorrect. 

It appears the following link describes another user with the same issue.

http://e2e.ti.com/support/data-converters/f/73/t/710220

I have tried to cycle through the digits in order to get the calibration mass to be positive without any luck.

Please advise on how to rectify the issue.

Other Information

  • ADS1232 V1.2
  • My units are lbs if that makes a difference
  • I do not have the means to reflash the device

  • 0
    TI__Guru** 112725 points

    Hi Chris,

    Welcome to the E2E forum! SW4 and SW5 move through the digits and SW2 and SW3 move the position of the cursor/menu item.  Try moving the cursor using SW2 until it is under the '-' or the '0' and then try to use SW4 to move the number positive.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Prodigy 40 points

    Hi Bob,

    Thanks for the response.  Unfortunately, I have tried to to move the digit positive as you suggested without any luck,

  • 0 in reply to Chris Owens
    TI__Guru** 112725 points

    Hi Chris,

    Just so we are clear, the '--' adjacent to the CW ('CW--') is normal. The 'CW-- --' would be negative.  In your picture you showed on the LCD 'CW-- -- 03.lb'm but it is not clear what position is blinking.  If the '3' is flashing you need to move the cursor by pressing the SW2 button.

    Unfortunately there are only a few buttons and the functions relating to them can be a bit confusing.  Once in the configuration mode, the SW3 and SW4 move through the various configuration menu items and the SW1 and SW2 change the option.  However, the calibration option is slightly different.  In this option the SW3 and SW4 move the cursor through the various positions before exiting the menu item.  In the case of the least significant digit, the response appears to sometimes get out of sync and is only correctable if you move the cursor left of the least significant digit.

    Let me know what you are currently seeing on the LCD, and the position that is blinking.  Also describe specifically what happens as you press the various switches.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Prodigy 40 points

    Bob,

    I appreciate your help.

    The position that is blinking in the image is the `--` sign. The blinking digit is the not the digit that gets modified when SW2 or SW3 is pressed... the digit to the right of the blinking digit is modified.   The least significant digit (tenths digit?) is not present on the screen but is modifiable by the SW2/SW3 presses.  I can see this due to the fact the 1's digit will change with every 10 presses on the least significant digit.

    I have tried to increment/decrement all 3 digits that are available 100s of times without any change in the minus sign.

  • 0 in reply to Chris Owens
    TI__Guru** 112725 points

    Hi Chris,

    I finally found a combination where I get the control to stick and the value will always be negative.  There appears to be a rollover issue relative to the position of the cursor.  Have you tried pressing the RESET and simply starting over?  I will continue to investigate to see if there is another way to get the values to return to a positive value once it appears to be stuck negative.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Prodigy 40 points

    I unfortunately stored the values to the EEPROM and the RESET button has no effect.

    At this point is it possible to exchange the board I have for a new one?

  • 0 in reply to Chris Owens
    TI__Guru** 112725 points

    Hi Chris,

    This is definitely a bug in the firmware.  The maximum value is to be limited to 99.9 and the minimum to 0. There should never be a negative number.  The validation to force the value within the range of 0 to 99.9 is after the parameter is written to what is stored in flash instead of before.  Unfortunately I feel this will still be an issue with a new board as the firmware has the same bug. 

    I also stored a negative value to the flash and of course I had the same result as you in that the value stored is restored to memory upon reset.  On a positive note I was able to move the negative value to a positive value.  The reason is the number stored is a floating point number and not all of it is visible.  In the case of negative numbers the tens digit is not properly displayed and the code shifts the response to the ones digit.  So let's say the number stored was -150 and you see a flashing '-' sign and 50. If you press the SW4 button you will see a response of -40 which is adding a positive value to the negative number.  Pressing the SW4 switch again changes to 30 and so on.  It appears that as you press the button the number will just continue roll through the values of 9 to 0.  However what you are actually doing is adding a positive number to the CW value.  So depending on how negative the value is, pressing SW4 enough times will keep adding to the count until the negative number becomes positive.

    The number of times you need to press SW4 will depend on what number you actually stored to flash.  If you press SW3 you will subtract from the count and if you press this button 100 times, you will need to press SW4 100 times just to get back to the starting point.  So while you are in the Config menu, scroll through the options until the '-' is flashing and then only press the SW4 button until the number becomes positive.

    If you still can't get this to work, I can try to get you another board.  Please send me your contact information to:

    mailto:pa_deltasigma_apps@ti.com

    Best regards,

    Bob B