ProSoft Technology ILX34-AENWG - Manual (Page 59)

Planning and Implementing Wireless Networks PSW-PWD ♦ ProSoft Software
User Manual ProSoft Wireless Designer
ProSoft Technology, Inc.
Page 59 of 91
July 8, 2009
Will the equipment be relocated over time?
For processes that move over time (such as mining operations) industrial
wireless can save significant costs since cabling does not need to be re-installed
every time the process moves. When designing a wireless network for this
purpose, it is prudent to understand the long term plans for the process (where it
will move) and design the wireless network accordingly.
Are there any special regulations and environmental requirements?
It is important to find out the local government regulations regarding RF use. The
wireless network hardware must meet the RF and certification requirements of
that country. This is specific to the country of installation and can impact
frequency band, RF power output, and RF modulation methods. Local
regulations may limit the performance of the wireless network.
Also, some installation sites (such as oil and gas systems) require special
certifications for installation in hazardous rate locations where explosive
materials may be present. It is important to have proper approvals such as Class
I, Division 2 or ATEX for these installations.
Each site requires a power source to power the wireless modem. If power is not
available (such as for a repeater site), then a battery with solar recharge may be
required.
Finally, review of environmental conditions of each site is necessary to ensure
network reliability and hardware life. It is important to choose wireless equipment
that meets the temperature requirements (often extreme at industrial sites) and
protect the equipment from moisture and corrosive materials.
5.2 Plan the Network
Once the application is defined, the next step is to plan the network. This
includes selecting the wireless technology, modem hardware, antenna types and
antenna coax.
What is the network topology?
The simplest wireless topology is point-to-point where two sites are connected
together for data exchange.
For SCADA networks, the most common topology is point-to-multipoint where
one master site communicates (and collects information) from multiple remote
sites.
Star Topologies are similar to point-to-multipoint topologies but permit
communication between all sites, not just master to remote/remote to master.
The most common example of a Star Topology is wireless networks for portable
computer access where an access point in the center of the star.