CHAPTER 3: SYSTEM INFORMATION
SNAP PAC R-Series Controller User’s Guide
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Segmenting the Control Network
If you need to segment the control system network from the main network backbone, you
can use the two Ethernet interfaces on either the SNAP PAC R-series or an S-series
controller. One interface can be connected to the enterprise network, and the other used
for the control system. See the diagram on
page 33
. (This implementation requires PAC
Project Professional. For more information, see the
SNAP PAC R-series data sheet,
form #1594
and the
SNAP PAC S-series data sheet,
form #1584.) Or you might consider using a router,
network switch, or other gateway device.
NOTE: If you are using wired+wireless models, one of the segmented networks can be a wireless
LAN.
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.
