5.3.5 Fob Calibration Process

Perform the following calibration steps for each fob separately:

  1. If not done already, follow the procedure detailed in CARS Kit PC Evaluation Utility.
  2. In the System Configuration window, choose the fob to be calibrated in the “Selected Fob” drop-down list (see the following figure).
  3. Click the Fob ID button followed by the Calibrate Fob button.
    Figure 5-9. FOB Calibration
  4. Click the Next button within the Fob End-of-Line (EOL) Configuration window.
    Figure 5-10. FOB EOL Configuration Window
  5. Position the LF antenna module and the fob to align the X-axis of the fob with the LF antenna module axis, then click the Measure button. This measures the current X-axis RSSI signal amplitude and updates the result to the “Peak RSSI” field for the X-axis. Click the Measure button several times to ensure the peak value is stable (see the following figure).
    Note: When using the ATA5293-XPRO, the X-10013-002 antenna positioning is the same as the LF antenna module.
  6. Click the Next button.
    Figure 5-11. X-Axis Peak RSSI
  7. Position the fob to align the Y-axis, then click the Measure button. This measures the current Y-axis RSSI signal amplitude and updates the result to the “Peak RSSI” field for the Y-axis. Click the Measure button several times to ensure the peak value is stable (see the following figure).
    Note: When using the ATA5293-XPRO, the X-10013-002 antenna positioning is the same as the LF antenna module.
  8. Click the Next button.
    Figure 5-12. Y-Axis Peak RSSI
  9. Position the fob to align the Z-axis, then click the Measure button. This measures the current Z-axis RSSI signal amplitude and updates the result to the “Peak RSSI” field for the Z-axis. Click the Measure button several times to ensure the peak value is stable (see the following figure).
    Note: When using the ATA5293-XPRO, the X-10013-002 antenna positioning is the same as the LF antenna module.
  10. Click the Next button.
    Figure 5-13. Z-Axis Peak RSSI
  11. Click the Measure button to have the fob perform an internal RSSI measurement and display the results in the “Measured Int. RSSI” field. This measurement is performed by an internal current source, which drives each of the fob’s 3-axis LF antenna coil circuits (see the following figure).
    Note: When using the ATA5293-XPRO, the X-10013-002 antenna positioning is the same as the LF antenna module.
  12. Click the Next button.
    Figure 5-14. Internal RSSI Measurement
  13. Click the Configure button to store the compensation constants into the fob EEPROM (indicated by a blinking LED on the ATAB5702A fob board). Before closing the Fob EOL Configuration window, wait until the LEDs stop blinking.
    Note: If there is only a slight difference in the Int. RSSI values, check the No change check box.
    Figure 5-15. Slight Difference in Internal RSSI
    Note:
    • If there is a significant difference between the “Measured Int. RSSI” and the “EEPROM Int. RSSI” fields, check the “Update EEPROM” check box. This can occur when the fob's components age over time or if a change in the circuit has occurred (for example, evaluating a different 3D coil).
    • Checking the “Update EEPROM” check box updates the RSSI values currently stored in the EEPROM with the newly measured values.
    Figure 5-16. Significant Difference in Internal RSSI Values
  14. Click the LF Test button in the System Configuration window to check if the calibration values are stored in the EEPROM, and to display the RSSI values in the respective fields within the “PEPS Fob Actions” section. The “Ref. RSSI” values under the “PEPS Fob Actions” section must match the “Measured Int. RSSI” values from the Fob EOL Configuration window. Repeat the fob calibration if these values do not match.
    Figure 5-17. RSSI Values