Handling Disturbances At The Top Of The Tank - Emerson Rosemount 3308A Reference Manual

Service and Troubleshooting
October 2016
To set the Peak Detection Method to Threshold Intersection, do the following:
1. From the Home Screen, go to Service Tools > Echo Tuning > Advanced.
2. Under Peak Detection Method, select Threshold Intersection and then click Send.
3. Run Verify Level to compensate for any offset error (see
Intersection method. See
Figure 6-12. Thin Oil Layer on Top of Water, Peak Detection Method Set to Threshold Intersection
6.5.2

Handling disturbances at the top of the tank

Adjusting the Near Zone Threshold
The Near Zone Threshold is used to filter out disturbing echoes and noises at the top of the tank. By
default, this threshold is automatically calculated by the device, and is sufficient in most conditions.
However, in the case of unfavorable conditions, you might need to manually set the Near Zone
Threshold. This may for example be the case if a Single Lead probe is mounted in a narrow nozzle, if the
end of the nozzle protrudes into the tank, or if there are disturbing obstacles in the Near Zone (referred
to as the region between 0-3.3 ft (0-1 m) below the Upper Reference Point.
96
"Verify Level" on page 67
Offset error
Actual product surface
is ignored
Surface detected at first intersection with
Surface Threshold, even when there is an
oil peak
for further instructions.
Surface Threshold
Reference Manual
00809-0100-4308, Rev BB
Figure 6-12) introduced by the Threshold
Service and Troubleshooting