• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 31 subscribers
  • Views 705 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMP006 Calibration S0 problem

Sheng Luo
Intellectual 430 points
Other Parts Discussed in Thread: TMP006

Hi,

I still have problems with S0 calibration. I attached a spread sheet to depict my questions.

As depicted in 'sensitivity change' sheet , I run a matlab script to get customer's a1 and a2. Afterwards,
I evaluate these two groups of a1 and a2.
      |   TI               | Customer
-------------------------------
a1  | 1.75E-03   | 5.77E-03
a2  | -1.68E-05  | -5.63E-05
-------------------------------

As shown in 'sensitivity change' sheet, the TI's sensitivity change over temperature is flatter than that of customer. Two-point calibration is done in 'Calibration' sheet. Two S0 values are achieved. They are used to create two sheets to compare measured values and expected values. TI-case is based on TI solution. Customer-case is based on customer solution. I find temperature drift of customer is better than that of TI.

My questions are
1) How to select two extreme points to achieve better S0 in calibration stage? What's your proposal?
2) How to achieve optimum values of a1 and a2?
3) How to fit expected values better?

Thanks.

BRs,

Luo Sheng
7024.TMP006 S0 Calibration Question.xlsx

  • 0
    TI__Genius 15760 points

    Hi Luo,

    Thanks for using TI E2E Forums. I have forwarded this question to the IR thermal systems engineer. Please allow him some time to review it and get back to you.

    Mayrim

  • 0 in reply to Mayrim Verdejo
    TI__Expert 3370 points

    Hi Luo,

    The temperature range of calibration is very narrow, only 54-56C for Tobj and 31-33C for Tdie. Within a narrow range, noise in the system may dominate the changes in signal due to changes in temperature. I would first recommend to expand the temperature range for at least Tobj to span 20C from the min to the max temperature. Then take measurments at roughly equal spaced intervals, maybe every 3 to 4 degrees C.

    As regards the s0 co-effs, these are dependnet on the material proprtie, specficiacaly the emissivity, and the object height and distance which determines the Field of View.  The TI co-effis are for a laboratory black body with emissivity of 0.94 viewed with a 120 degree field of view. . If the customer object has a different emissivity or field of view, then it will require a different set of co-effs.

    The TMP007 data sheet has a discussion of the Field of View and emissivity which applies to the TMP006 also. The TMP007 data sheet contains some examples of calibrations.  In addition, the TMP007 calibration guide should be appearnig on the web soon.

    Regards,

    Werner

  • 0 in reply to Werner Metz
    Intellectual 430 points

    Hello Werner,

    Yes, you are right. The temperature range shown in excel sheet is very narrow. Wide range was used in calibration stage although it was not shown in excel sheet.

    Thanks to your information. I have looked in TMP007 datasheet. Now SBOU142 — TMP007 Calibration Guide is very important to me because of time to market. When will SBOU142 be available on the web?

    BRs,

    Luo Sheng