2
2
P R E - I N S TA L L AT I O N C O N S I D E R AT I O N S
Choosing a location:
(See Figure 1)
1) Anticipated Range:
Plan installation to stay within the
range of the antenna selected. Monitor's standard
antenna (small rubber duck style) can achieve dis-
tances of 5000 ft (1 mile) or greater in ideal conditions.
Longer transmission distances can be achieved with
higher performance antennas.
2) Idealizing Range:
The 900MHz frequency band is
capable of propagating around obstacles. However,
optimum performance is achieved when antennas are
positioned in the line of sight of each other. Whenever
possible, select antenna locations that are elevated
and where the signal can travel without being impeded
by large steel obstacles (such as the steel buildings).
An example of an ideal installation is as follows: One
Wireless Communication Interface (radio/antenna) is
on an office roof wired to the control system (i.e.
Silo
Track
™ system) and the second Wireless
Communication Interface (radio/antenna) is on the top
of the silo attached to a safety railing wired to the
sensors.
3) Cabling effects:
Due to the low transmission power of
the radio, it is preferable to keep the antenna as close
to the Wireless Communication Interface (radio mod-
ule) as possible. Whenever possible mount the anten-
na directly to the Wireless Communication Interface
(radio module). In some challenging applications, it
maybe necessary to install a higher performance
antenna that requires co-axial cabling between the
radio and the antenna. The co-axial cable introduces
loss into the system thereby negating some benefit of
the better antenna. In these applications, keep the
coaxial cable as short as possible. Monitor's standard
length is three feet (perhaps just long enough to reach
past/through a metal barrier). It is always preferable
to use the hardwired medium (RS-232/RS-485) to span
the distance from the control system/sensors to the
Wireless Communication Interface (radio module) than
to use extended lengths of coaxial cable to span the
distance between the Wireless Communication Inter-
face (radio module) and the antenna.
The
Silo
Patrol
®
inventory monitor “smart” sensors (Refer
to Bulletin 343A) can be used in conjunction with the
Silo
Track
™ Inventory Management PC-Based Software
(Refer to Bulletin 343B). Communication between the
Model SMU “smart” sensors and the
Silo
Track
software is
accomplished via 2-wire RS-485 communication format.
The
Silo
Patrol
Wireless Communication Interface can be
used to replace the RS-485 wiring between the “smart”
sensors and the PC. With reliable and affordable tech-
nology, the
Silo
Patrol
Wireless Communication Interface
can be used to lower the cost of installation and to over-
come obstacles that make hardwiring impractical or
impossible.
Figure 1
