Flexar® Guided Wave Radar
The Flexar® continuous
level measurement system is a smart guided wave radar device
used for monitoring the level of powders, granules and other
bulk solids as wells as many liquids and slurries.
Proven Flexar® Technology Installed
Thousands Of Bulk Solids Applications
Reliable TDR (a.k.a Reflex Radar)
Technology Used For Decades
“Smart” Transmitter Output
For Use With
Industry-Leading SiloTrack™ Inventory
When All The Pieces Fit Just Right!
The Flexar® continuous level measurement
system is a smart guided wave radar device used for monitoring
the level of powders, granules and other bulk solids. It is also
suitable for use with a variety of liquids and some sluries.
It is used in a wide assortment of vessels and industries for
measuring levels up to 200ft (60m) in height.
Bringing the Pieces Together: Manufactured at our facility
in Elburn, IL, we uniquely combine this proven and strategically
acquired technology with almost five decades of expertise and
focus in powder and bulk solids applications, and with our
management software interface. Monitor Technologies uniquely
provides the best solutions in level measurement and inventory
management of powders and bulk solids.
The Flexar guided wave radar level sensor and/or transmitter
requires no field calibration or re-calibration and can be
setup easily by customer personnel without the use
of any special tools or training. Flexar units are
suited for almost any application, can operate with process
temperatures up to 392° F (200°C), can be provided
with a variety of process connections and can work reliably
with materials having a wide
range of bulk densities and dielectric constants.
available with a choice of two outputs. The standard output
is a “smart” interface for use with SiloTrack™ Version
3.5 PC-based inventory management software. This network-ready
software provides a flexible graphical interface for up to
128 “smart” output
sensors. In lieu of this “smart” output, an optional
analog output is also available.
Flexar® smart guided wave radar level
sensors and transmitters operate using TDR (time domain reflectometry)
principles that were first developed in the middle part of
the 20th century for use in the geological field. Further development
of TDR led to its use in the telecommunication industry for
detecting breaks in cables. Flexar technology was pioneered
in the mid-late 1990’s when TDR was applied to level
measuring applications within the process measurement industry.
In the application
of TDR for process level measurement micro-pulses are continuously
transmitted along a probe or “wave guide” at
the speed of light. As soon as the pulses reach the material
surface they reflect back to the sensor electronics unit. The
time-of-flight of the pulses is calculated and directly related
to the distance from the point at which the sensor is mounted
on the top of the vessel to the material surface (level). The
output from the electronics is continuously updated as the
level of the material surface changes.
Flexar smart guided
wave radar sensors are equipped with two
different measuring modes. In the Direct measuring mode the
pulses directly reflect off the material surface back to the
unit. This mode is used in applications where the material
being measured has a dielectric constant as low as 2.1 for
probes and 1.8 for twin-cable probes.
For materials with dielectric
constant below the above mentioned limits, down to as low
as 1.4, the second measurement mode
is used. This is the TBF (tank bottom following) mode, which
used due to the inability of the pulses to adequately reflect
off of the surface of very low dielectric materials. In this
measuring mode the Flexar sensor has a “short circuit” at
the bottom of the probe at a precisely known distance from
the sensor’s mounting point.
In the TBF mode the pulses travel through air at the speed
of light and then pass through the material in the vessel at
a slower speed, dependent on the specific dielectric constant.
The pulses are reflected at the short circuit back up the probe.
Flexar sensors in the TBF mode measure the time between the
emission and reception of the pulses from the probe short circuit.
Because the return time of a pulse when no material is present
(through air) is known, we can determine the difference in
time between the time-of-flight when empty and the time-of-flight
when filled as being directly proportional to the material
level in the vessel.
The Flexar® smart guided
wave radar continuous level measuring system can be used in
a wide variety of applications, including powders, coarse/fine
granular solids, liquids, foodstuffs and even some corrosive
substances. Flexar sensor technology is proven in many difficult
applications including those where dust levels make it difficult
for other technologies to perform reliably, especially at long
Typical Applications include, but
are not limited to:
Please consult Monitor's
Technical Support Dept. to verify that the Flexar is the
best fit for your specific application. Certain conditions
(like target material dielectric, silo height, etc.) need
to be taken into consideration.
The maximum range for solids applications
is limited to 100ft (30m) due to load limits possible from
ranges. Liquid applications can extend up to 200ft (60m).
Any application requiring a continuous level measurement
where the process temperature does not exceed 392° F (200°C)
(40bar) is possible. The 316 stainless steel probes and threaded
or flanged process connections make the Flexar continuous
level measuring system ideal for almost any bulk solid and
application. To ensure a successful and reliable application,
the Monitor Technologies factory-based technical support
group to see if Flexar is right for your application.
Remote Inventory Monitoring
If material levels need to be monitored at one or many
locations (i.e. your facility, a location down the street,
or a plant
on the other side of the world) the Flexar system can
provide continuous, reliable and accurate measurements. Using
3.5 software, inventory monitoring from remote locations
has never been easier.
No Moving Parts.
Unlike weight and cable based systems of old, Flexar® guided
wave radar level sensors are state-of-the-art and use a time-proven
electronic method for continuous measurement of a material
level. This non-mechanical means of measurement helps ensure
With Dielectric > 1.4
(TBF Mode). Flexar sensors are capable of sensing and measuring
the level of most any material. Materials with dielectric
constants below 1.8-2.1 require the use of our TBF (tank
bottom following) measuring mode.
Unaffected By Dust
And Changes In Material Properties.
The technology employed in Flexar
units has been proven to be unaffected by airborne dust
even during pneumatic filling operations. Unlike through-air
technologies such as ultrasonic, through-air radar and
laser, Flexar can reliably measure in dusty environments
without sacrificing performance or reliability.
Range Of Probes.
In order to handle the assortment of applications possible
with Flexar, Monitor offers a range of probe styles including
single-cable, twin-cable and single-rod. All probes are
constructed of 316 stainless steel, have traction load
handling capabilities suitable for their respective applications
and are easily field replaceable. Consult with Monitor’s
factory-based technical support personnel to select the
right probe style for your application.
Assortment Of Process Connections.
To meet the required bulk solids and liquid applications
we have prepared a selection of process connections that
will ensure a smooth and simple installation. Flexar
sensors can be provided with 1-1/2” NPT, 1-1/2” BSP
G, 2” ANSI or DIN DN50PN40 flange connections.
Probe type will determine the available process connections.
Dual Compartment Enclosure.
The Flexar smart guided wave radar sensor uses an enclosure
with two compartments, each with its own access cover.
This allows separation of access for wiring and setup/display.
The setup/display compartment is provided with a cover
window allowing local viewing of the LCD display. In
addition, every unit is provided with either two 1/2” NPT
conduit entrances (NPT threaded and ANSI flanged process
connections) or M20 cable connectors (BSP threaded and
DN flanged process connections).
Local LCD Display And Setup.
Each sensor includes a built-in user interface consisting
of a three-line backlit LCD display, three pushbuttons
and three magnetic sensors (used to perform setup and
interact with the unit without having to remove the display
Universal Power Supply.
Power supply choices include a universal high voltage option
100-240 VAC and a low voltage 24 VAC/VDC option.
Choice of outputs.
The standard output for all Flexar guided wave radar units
is a “smart” RS-485 communications interface
for use with SiloTrack™ Version 3.5 inventory management
software. In lieu of this “smart” interface
an analog 4-20mA output is available.
Remote electronics available.
The standard unit includes the electronics integrally mounted
with the sensor. However, remote mounted electronics
is optionally available for applications where the electronics
are desired to be mounted away from the probe due to
extreme vibration, temperature or for convenient access
to the local operator interface. The remote electronics
version includes a pre-wired 16.4ft (5m) interconnecting
All units include the CE
mark and are approved for use in ordinary locations.
Single Cable 0.16” (4mm)
Single Cable 0.31” (8mm)
Single flexible 316 SS cable with counterweight
Single Flexible 316 SS cable with counterweight
Vessel height < 150ft (45m); Liquids; Some solids
Vessel height < 100ft (30m);
Powders and other bulk solids (consult Monitor)
Twin Cable 0.16” (4mm)
Single Rod 0.38” (10mm)
Two flexible 316 SS cables with spacers between them at
intervals, w/ counterweight
Vessel height < 10ft (3m); Liquids; Some powders
Interface Control Console
The HMI2 operator interface control console provides convenient,
local interface for Monitor’s “Smart” RS-485
SiloPatrol® SMU SE cable-based inventory monitoring sensors
and/or Flexar® guided wave radar sensors. HMI2 allows for
monitoring up to 32 SMU and/or Flexar sensors. The multi-functional
HMI2 controls sensor operations, displays measured and calculated
data and performs/displays system and sensor diagnostic messages.
The HMI2 is easily programmed to display calculated level,
volume, weight or percent in addition to the basic distance
measurement. Manual readings are taken by depressing the MEAS
button, followed by the channel number, followed by ENTER.
The HMI2 can also be programmed to operate the SMU “Smart” RS-485
sensors automatically. Menu options allow the user to select
days of SMU operation (such as Mon.-Fri.), time window (such
as 7 a.m.-3 p.m.) and measurement interval (minimum 30 minutes).
3.5 Inventory Management Software provides users with
an unsurpassed, flexible graphical interface for Flexar® smart
guided wave radar sensors. Together, SiloTrack Server
and Client software can provide inventory monitoring
and management to a virtually unlimited number of users,
both internal and external to your facility. This allows
easy implementation of remote monitoring and vendor managed
Monitor up to 128 sensors/with up to
5 sensors per vessel
to setup and use
monitoring via LAN, Internet/WAN or dial-up
3-line; Backlit LCD; 3 pushbuttons;
3 magnetic sensors for setup without cover removal
Materials of Construction:
Aluminumm, powder coated
316 Stainless Steel
316 Stainless Steel
16.4’ (5m) pre-wired interconnection cable
Dielectric = 80 (water)
Top = 15.75” (400mm)
Bottom = 0.8” (20mm)
Dielectric = 2.4 (oil)
Top = 19.7” (500mm)
Bottom = 3.9” (100mm)
Dielectric = 80 (water)
Top = 9.8” (250mm)
Bottom = 0.8” (20mm)
Dielectric = 2.4 (oil)
Top = 13.0” (330mm)
Bottom = 0.8” (20mm)
ENCLOSURE TYPE 4X, IP66
Integral Electronics Only
CSA(US/C) Class I, Div 1,2, Groups B, C, D;
Class II, Div 1,2, Groups E, F, G; Class III
Monitor Technologies LLC warrants
each Flexar® guided wave radar continuous
level measurement system and HMI2 it
manufactures to be free from defects in material and workmanship
under normal use and service within two (2) years from the
date of purchase. The purchaser must give notice of any defect
to Monitor within the warranty period, return the product intact
and pre-paid transportation charges. The obligation of Monitor
Technologies LLC under warranty is limited to repair or replacement
at its factory. This warranty shall not apply to any product
which is repaired or altered outside of the Monitor Technologies
LLC factory, or which has been subject to misuse, negligence,
accident, incorrect wiring by others or improper installation.
Monitor Technologies LLC reserves the right to change the design
and/or specifications without prior notice.
The TrueCap® Model MK-2 RF Capacitance
point level probe is designed to provide a superior and stable sensitivity
threshold making it suitable for a variety of powder / bulk solids
and some liquid or slurry applications.
Advanced features of the
Model MK-2 include: > Automatic immunity to material build-up on the
probe by its driven shield design > Push-button calibration > Enhanced temperature
Maximized reliability via smart sensing algorithms like “self-validating” fail-safe
protection > Visible status LED on ordinary location
units > Versatility through a variety of configuration
options including: hazardous location version, split architecture
design, quick-connect process connection, stub probe, cable extensions,
solid extensions, Nylon® probes, Ryton® - equiv. probes,
A practical application for the TrueCap would be to use this level sensor where
a residual material build-up on a different sensor would cause a false
material level indication.
Principle of Operation for the TrueCap RF Capacitance Level Probe:
wall and the active probe element establish an impedance reference between each
other when exposed to air which has a dielectric constant of 1. When materials
with a dielectric constant greater than 1 are in close proximity to the probe,
the impedance of the sensing field between the sensor and the vessel
wall will change. Once the amount of change exceeds a threshold that
was electronically determined during the calibration process, an
output relay will either be energized or de-energized depending upon
the position of the fail-safe selector on the probe’s electronic
circuit board. A change of as little as .5 pico-farad is all that
is necessary for the probe to sense the presence of material.