
98
Reference Manual
00809-0100-4811, Rev DA
Section 6: Service and Troubleshooting
January 2015
Service and Troubleshooting
Figure 6-5. After Changing the Amplitude Threshold the Transmitter Detects the Interface
6.2.4 High level rates
The measurement signal is filtered in order to minimize the influence of disturbing noise. In
most measurement situations, this does not have a noticeable effect on the response time to
level changes. However, if high level rates occur, it may be necessary to reduce the damping
value to allow the transmitter to respond quicker. If there is too much noise, the damping value
may be increased in order to get a stable measurement signal.
You can use the RCT software or a Field Communicator to change the damping value. For the
HART Communicator use the key sequence [1, 3, 5].
In the RCT software, open the Setup > Output tab and enter the desired damping value:
The damping parameter determines how quickly the transmitter responds to level changes and
how robust the measurement signal is against noise. Technically, a damping value of 10 means
that in 10 seconds the output from the transmitter is about 63% of the new level value.
Consequently, when there are rapid level changes in the tank, it may be necessary to decrease
the damping value for the transmitter to be able to track the surface. On the other hand, in
noisy environments, and if level rates are low, it may be better to increase the damping value to
have a stable output signal.
The amplitude threshold is adjusted
below the peak to allow the interface
peak to be detected
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