Dear Tryu,
I've made some modifications to the Meter Example VI shipped with LabVIEW.
1) Changed the way that the VI looked for the saved images. It will now look in the folder specified by the control "base path". It currently uses Speedo1.png for the full negative scale picture and Speedo4.png for the full positive scale picture. Because Speedo4 is not an actual full positive scale picture, the arc that is generated to describe the needles path is off (see attached screenshot).
2) Changed the full scale percentage and Meter values to correspond to your gauge. You will need to change the constant that is multiplied by the percentage of scale to correspond to the position of the needle in the image you use for the full positive scale calibration (If the needle reads '140', then specify 1.4).
3) Wired a true constant to the IMAQ Read Meter VI to correspond to a white needle on a black background.
It seems to work well except for one of the images, and I believe it will work better when you give the VI full negative and full positive scale pictures for the calibration, or at least at equal angles with respect to the centerline (say at 30 and 120 for your particular gauge).
Please let me know how it goes, and if you have any additional questions.
Best Regards,
~Nate
