How To Configure The Algorithm - Honeywell SLG 700 User Manual

7.8.7

How to configure the algorithm

Under normal circumstances, the transmitter will automatically find the level of the surface and
interface (if applicable) using the configuration that was shipped from the factory:
1. Step through the basic configuration and make sure that all entries are correct.
2. Review the Probe Parameters under Advanced Configuration and ensure that all
entries are correct.
Capture an echo curve as described in section
3.
4. Navigate to the Correlation Algorithm page and load the captured echo curve.
5. Select the reflection model (Reference, Surface, Interface or End of Probe).
The selected model appears on the upper graph as a brown line to distinguish it
6.
from the blue echo curve.
7. Click and drag cursor to move model over relevant part of the curve. The example
curve shown in the figure below represents a scenario of a two liquid non-flooded
application with oil on top of water. In the example the transmitter has correctly
located the surface of the upper oil layer, but has failed to find the interface
boundary between the oil and water due to a model mismatch. In this case the
Interface model should be selected and dragged to a location to the right of the
Surface reflection where the interface is known to be.
8. The closer the model shape matches the curve shape, the lower the Objective
Function value, as shown in the lower right-hand corner below the bottom graph. In
the example, the brown Interface model does not match the blue curve at the
selected position (240 cm) so the Objective Function value is high (greater than 1).
9. Zoom view: Use the mouse to draw a zoom box around the model, then click and
drag the model position for best match to the curve. Notice that by dragging the
model over the similarly shaped blue curve at 338cm, the Objective Function value
has decreased from 1.004 to 0.658, indicating a higher correlation between the
shapes.
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Figure 24: Adjusting the Correlation Algorithm
TIP: By slowly dragging the model back and forth over the curve you can
home in on the position with the lowest Objective Function value.
SLG 700 Series HART Option User's Manual
7.9.4.
Revision 5