Honeywell SLG 700 Option Manual page 174

Correlation Algorithm
The method by which the distance to product surface and distance to interface is found is based on
correlation between the measured echo curve and reflection models.
The algorithm slides the models across the echo curve and at each step calculate the difference
between the model and the echo curve, referred to as the Objective Function.
Typically the smallest value of the Objective Function corresponds to the level selected by the sensor
algorithms but the values must be below a user defined threshold. In case of multiple local minima,
there is additional logic to select the best candidate.
The final best candidate is used to calculate the distance to the product surface and/or the distance to
interface.
Page 158 FOUNDATION Fieldbus Option User's Guide Rev. 3.0