Reference Information; Detector Description; Theory Of Operation; Time Domain Reflectometry (Tdr) - Genesis ED1 Installation And Operating Manual

63-601 Genesis Models ED1 & ED2 Multiphase Detector
2.0

Reference Information

This section presents an overview of the operation of the
Genesis Multiphase Detector, information on troubleshoot-
ing common problems, listings of agency approvals, lists of
replacement and recommended spare parts, and detailed
physical, functional, and performance specifications.
2.1

Detector Description

The Genesis is a 24 VDC (SELV) powered Multiphase
Detector utilizing Time Domain Reflectometry (TDR) to
detect various layers of emulsion within a vessel. The
Genesis is comprised of three basic components:
• A remote top of probe housing
• A base of tank main electronics housing
• Flexible interconnecting conduit with mounting bracket
2.2

Theory of Operation

2.2.1 Time Domain Reflectometry (TDR)

TDR uses pulses of electromagnetic (EM) energy to measure
distances or levels. When a pulse reaches a dielectric discon-
tinuity (created by the surface of a process medium), part of
the energy is reflected. The larger the dielectric discontinu-
ity, the larger the amplitude (strength) of the reflection.
TDR has been used for decades in the telephone, computer,
and power transmission industries. In these industries, TDR
is used to successfully find wire or cable breaks and shorts.
An EM pulse is sent through the wire, traveling unimpeded
until it finds line damage due to a break or short. A reflec-
tion is then returned from the damaged area of the wire,
enabling a timing circuit to pinpoint the location.
In the typical TDR level transmitter, a waveguide with a
characteristic impedance in air is used as a probe. When part
of the probe is immersed in a material other than air, there
is lower impedance due to the fact that a liquid will have a
higher dielectric constant than air. When an EM pulse is
sent down the probe and meets the dielectric discontinuity
that occurs at the air/liquid surface, a reflection is generated.
What makes the Genesis special is the fact that, not only is
a signal sent down from the top of the probe, there is also a
signal being sent up from the bottom of the probe. This
unique (patented) combination of signals, along with
advanced internal algorithms allows the device to report
Upper Hydrocarbon level, the top of the emulsion, the
interface (water), and possibly sediment below.
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