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BE 57-660 Eclipse Model 700 Guided Wave Radar Transmitter
3.2.5 Overfill Capability
Although agencies like WHG or VLAREM certify Overfill
proof protection, defined as the tested, reliable operation
when the transmitter is used as overfill alarm, it is assumed
in their analysis that the installation is designed in such a
way that the vessel or side mounted cage cannot physically
overfill.
However, there are practical applications where a GWR
probe can be completely flooded with level all the way up
to the process connection (face of the flange). Although the
affected areas are application dependent, typical GWR
probes have a transition zone (or possibly dead zone) at the
top of the probe where interacting signals can either affect
the linearity of the measurement or, more dramatically,
result in a complete loss of signal.
While some manufacturers of GWR transmitters may use
special algorithms to “infer” level measurement when this
undesirable signal interaction occurs and the actual level
signal is lost, the ECLIPSE Model 700 offers a unique solu-
tion by utilizing a concept called Overfill-Safe Operation.
An Overfill-safe probe is defined by the fact that it has a
predictable and uniform characteristic impedance all the
way down the entire length of the waveguide (probe). These
probes allow the ECLIPSE Model 700 to measure accurate
levels up to the process flange without any non-measurable
zone at the top of the GWR probe.
Overfill-safe GWR probes are unique to ECLIPSE GWR,
and coaxial probes can be installed at any location on the
vessel. Overfill-safe probes are offered in a variety of coaxial
designs.
3.3
Troubleshooting and Diagnostics
The ECLIPSE Model 700 transmitter is designed and engi-
neered for trouble-free operation over a wide range of oper-
ating conditions. The transmitter continuously runs a series
of internal self-tests and displays helpful messages on the
large graphic liquid crystal display (LCD) when attention is
required.
