Figure 6-2: Threshold Principle
3.0
$
$
%
&
%
'
(
A. The echo peak is below the threshold (dotted line) and is suppressed by the device.
B. This echo peak is interpreted as the product surface, since it is the first peak closest to
device that is above the surface threshold.
C. Threshold
D. Amplitude
E. Distance
Related information
Guidelines for setting the amplitude thresholds
Normally, the amplitude thresholds are automatically set by the transmitter, and no
manual settings are needed. However, due to the properties of the product, it may in rare
cases be necessary to adjust the amplitude thresholds for optimum measurement
performance.
Guidelines for setting the surface threshold
Before changing the Surface Threshold, ensure the product level is at least 20 in. (0.5 m)
from the lower side of the device flange.
•
Surface Thresholds should never be set to values less than 4 Cnts.
•
Set the Surface Threshold to about
⅓
of the weakest surface echo amplitude in the
measuring range.
Service and troubleshooting
Reference Manual
February 2020
00809-0100-4308
120
Rosemount 3308 Series
Summary of Contents for Rosemount 3308A
Page 8: ...Contents Reference Manual February 2020 00809 0100 4308 viii Rosemount 3308 Series ...
Page 10: ...Introduction Reference Manual February 2020 00809 0100 4308 10 Rosemount 3308 Series ...
Page 22: ...Transmitter overview Reference Manual February 2020 00809 0100 4308 22 Rosemount 3308 Series ...
Page 74: ...Installation Reference Manual February 2020 00809 0100 4308 74 Rosemount 3308 Series ...
Page 96: ...Configuration Reference Manual February 2020 00809 0100 4308 96 Rosemount 3308 Series ...