Emerson Process Management 5300 manual Use Automatic Echo Tracking Settings, Damping

Reference Manual

00809-0100-4530, Rev BA July 2009

Rosemount 5300 Series

Use Automatic Echo Tracking Settings

When this check-box is selected, the transmitter automatically sets the echo tracking parameters to a constant value based on the configured tank environment and measurement mode.

Echo Timeout: defines the time in seconds before the device should start to search for a surface echo outside the Close Distance window after it was lost. After an echo was lost, the device does not start searching (or set Invalid Level) until the specified time has elapsed. In some applications, especially with solid products or applications with foam, the surface echo may disappear for periods of time. This value can be increased to prevent the device from entering alarm mode too early after the surface is lost.

Close Distance: defines a window centred at the current surface position where new surface echo candidates can be selected. The size of the window is ±Close Distance. Echoes outside this window will not be considered as surface echoes. The device will without delay jump to the strongest echo within this window. This value can be increased if there are rapid level changes in the tank. If the value is too large the device might select an invalid echo as the surface echo.

Damping

The Damping parameter defines how fast the device reacts to a change of the level value (step response). A high value makes the level steady but the device reacts slowly to level changes in the tank. A low value makes the device react quickly to level changes but the presented level value can be somewhat jumpy. The default value is 2 seconds. Note that increasing the damping value will also prolong the system response time. The damping value can also be changed from the Output, General tab.

C-13