Horizon
™
Model 704
Guided Wave Radar
Level Transmitter
D E S C R I P T I O N
The Horizon Model 704 Transmitter is an intermediately
priced 24 VDC, loop-powered, liquid level transmitter
based upon Guided Wave Radar (GWR) technology.
The transmitter is designed to provide all of the
performance advantages of GWR. Available in a non-
rotatable, single compartment plastic or aluminum
housing, this transmitter offers simple configuration
with three push buttons and a 2-line
×
8 character
liquid crystal display. The Model 704 covers a broad
application range by utilizing coaxial and twin rod
probes.
T E C H N O L O G Y
Horizon Guided Wave Radar is based upon Time
Domain Reflectometry (TDR). TDR utilizes pulses of
high frequency electromagnetic energy transmitted
down a probe. When a pulse reaches a surface that has
a higher dielectric than the vapor space in which it is
traveling, the pulse is reflected. High-speed timing
circuitry precisely measures the total transit time and
provides an accurate measure of the liquid level.
F E A T U R E S
•
Two-wire, 24 VDC, loop-powered transmitter
•
HART
®
communications (optional)
•
Varying dielectric constant or specific gravity
will have minimal effect on performance
A P P L I C A T I O N S
MEDIA:
Liquids or slurries; hydrocarbons to water-
based media (dielectric constants from 1.7 to 100)
VESSELS:
Most process or storage vessels up to rated
probe temperature and pressure
CONDITIONS:
Virtually all level measurement and con-
trol applications including those process conditions
exhibiting visible vapors, turbulence and varying dielec-
tric media or specific gravity
•
Probe designs up to +400° F (+200° C),
1000 psig (70 bar)
•
Available with coaxial and twin rod probes
•
No calibration or level movement required
•
16 foot (4.8 meter) measuring range
•
Lexan
®
or Cast aluminum housings
•
Optional 2-line
×
8 character LCD and 3-button
keypad
•
IS, XP, and Non-Incendive approvals