Emerson 3308A Rosemount 3308 Series, Reference Manual, Page: 100 / 198

88
Reference Manual
00809-0100-4308, Rev BA
Section 6: Service and Troubleshooting
December 2014
Service and Troubleshooting
By adjusting the Surface Threshold the product surface is properly detected as illustrated in
Figure 6-6 :
Figure 6-6. Echo Curve Plot after Surface Threshold Was Adjusted
Example 2: Interface Peak not found
In interface applications where the bottom product has a relatively low dielectric constant
(<40), or if the signal is attenuated in the upper product, the amplitude of the reflected signal
from the interface is relatively low and difficult for the transmitter to detect. In such a case it
may be possible to detect the reflected signal from the interface if the Interface Threshold is
adjusted.
Figure 6-7 illustrates a situation where the Interface Threshold is too high. The signal amplitude
peak at the interface between the upper and lower products is not detected in this case.
Figure 6-7. Echo Curve Plot Indicating that the Interface Threshold for the Interface Peak Is
Too High
100
80
60
-60
40
-40
20
-20
0
100
50
0
150
200
250
After Surface Threshold is
adjusted the product surface is
correctly detected
AM
P
LITUDE
DISTANCE
The Interface Threshold is
above the Interface Peak
AM
PLI
T
U
D
E
DISTANCE
Surface Threshold
Product Surface Peak