A stilling well may be used along with the
transmitter inside the tank. Stilling-well is a pipe
external to the sensor probe and float encasing the
entire assembly protecting it from surface agitation
or from physical damage due to the length of the
sensor probe. A depiction of a transmitter with a
stilling well is provided below.
Figure 4. Transmitter with a Stilling-well
When a stilling well is used, care should be
exercised when installing the tube to center it in
the chamber so that the float can freely travel
the entire length of the probe.
Stilling wells are
required for transmitters over 10 feet or the
instrument cannot be considered under
warranty.
Optional Features that are available with the
LTM-350 but
NOT the LTM-250
are:
1. HART Protocol, which enables:
a. A second digital output proportional to
an interface level (requires a second
float of different specific gravity)
b. A digital temperature output that
reflects the liquid temperature.
c. Advanced diagnostics and features
highly beneficial for commissioning,
troubleshooting or monitoring.
Up to two floats may be used with the LTM-350
only. The second float will typically sense the
interface level (the heavier of the two fluids) in the
tank. The specific gravity of the second float will be
such that it can be totally immersed in the lighter
fluid. The drawing below shows a transmitter with
dual floats, one for total level and the other for
interface level (also available with various process
connections).
Figure 5. Dual Output Transmitter
A dual output transmitter is also available
in a gage mount configuration. Consult factory
for further details.
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