Remtron
®
Engineered Systems
User Manual
12
9M02-9028-A021-EN
Version 4.0
5.
Operations
Cattron CommandPro
®
Wireless Control Systems are designed to control industrial machinery. These rugged
controls are built to survive the wear and tear of life in factories, mills and foundries.
These systems comply with operation requirements under Part 15 of the FCC Rules and Regulations. This means
that neither the operator nor the company need apply or register for a license to operate this equipment.
The basic system consists of a transmitter and a receiver. The transmitter sends commands to the receiver
through radio waves in the 900 MHz band. Receivers operate at 120 VAC 50/60 Hz power. Operation from other
power sources is also available.
5.1
How the System Works
5.1.1 Frequency
Cattron CommandPro
®
equipment operates in the 902 to 928 Megahertz (MHz) frequency band. A wavelength at
our frequency is 12.9 inches.
Like light, 900 MHz radio signals pass through glass and plastics, and reflect off of walls, buildings and metal
structures. Unlike light, 900 MHz radio signals penetrate all plastics including those opaque in color, as well as
thin-gauge steel, dry wood, dry concrete, plasterboard, fog and rain. However, the signal will not readily pass
through trees, earth, water, people, aluminium, copper and some window tints.
5.1.2 Range and Antenna Coverage
Antennas convert radio signals into radio waves and convert radio waves back into radio signals. They can send
and receive in all directions or in a single direction, depending on their design.
An omnidirectional antenna is like a light bulb, and a directional antenna is like a flashlight. Metal objects reflect
radio waves, just as a mirror next to a light bulb will reflect light. Metal objects near an antenna alter the intended
pattern of an antenna by either shading or reflecting signals.
Our s
tandard antennas are omnidirectional; they ‘see’ equally well in all directions. We have other antennas that
will ‘see’ further in one direction for special applications.
5.1.3 License-Free Channels
The 902 to 928 MHz spectrum accommodates many license-free users and is set aside by the FCC as an ISM
Band (Industrial, Scientific and Medical). We have the ability to change frequencies in this band and have 81
different channels that we can assign to the transmitter and receiver. The actual frequency is coded into the
receiver and transmitter at the factory but may be changed to one of the other 80 channels in the field if desired.
Other devices in this band include wireless phones, computer data links and inventory equipment. As a condition
of using this band, products must accept and handle interference from other users.
The 900 MHz band works well for most users, and not being burdened with licensing regulations is desirable. The
FCC has allowed 50,000 microvolts per meter field strength on this band, which is 250 times higher than other
unlicensed frequencies below the band. This allows our systems to operate very reliably in the presence of other
signals.
