NETWORKING
SNAP PAC R-Series Controller User’s Guide
24
Using the Controller in an Independent Network
The third way SNAP PAC R-series controllers can be used is by developing an independent network. An
independent network gives a high level of communication speed and volume, as well as high security. If you
have no existing Ethernet network, you can use off-the-shelf Ethernet components to build one. Consider
using industrial-grade Ethernet components for harsh and challenging environments.
You may also need a separate network for critical control applications. Again, the choice depends on your
requirements for data transactions, data security, and whether a near-deterministic system is necessary.
If you are building your own network, remember that each controller must have a
fixed
IP address. See the
PAC Manager User’s Guide
for more information on IP addresses.
Since Ethernet and TCP/IP are worldwide standards, there are a number of commercially available resources
for learning about building and maintaining such a network. One excellent resource is the
MCSE Training
Guide: TCP/IP
by New Riders Publishing; many others are also available. We strongly suggest you learn as much
as possible about the subject and plan your network carefully before beginning, in order to get the best
performance from your system.
Communicating with the System via Modem
A fourth way to use a SNAP PAC R-series controller is with a modem connection. This use is ideal for remote
installations (for example, a communication tower or a pipeline) or in other places where a wired Ethernet
network is not practical. Communication via modem uses the Point-to-Point Protocol (PPP) over an RS-232
link instead of an Ethernet link.
The system can dial out to a PC connected to a modem, or the PC can dial into the system, or both. If the
system is also communicating via Ethernet, the network ID for the PPP interface on the controller must be
different from the controller’s Ethernet IP network ID.
For more details on configuring the controller for use with a modem, see
.
Using the Controller in a Wireless LAN
A Wired+Wireless PAC-R (SNAP-PAC-R1-W or SNAP-PAC-R2-W) can also be used in a wireless local area
network (LAN) built with components that meet 802.11a, b, or g standards, depending on which works best
for your environment. Both ad-hoc and infrastructure modes are supported. The best security, however, is
available only in infrastructure mode.
Remember that you must use PAC Manager on a wired network to configure wireless communication
parameters, before you can use the PAC wirelessly.
Modem
Modem
Computer
Telephone lines
SNAP PAC R-series
controller and I/O on
rack
