NETWORKING
SNAP PAC R-Series Controller User’s Guide
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NETWORKING
From a physical standpoint, SNAP PAC R-series controllers can be networked in several ways:
•
Connected directly to a PC or controller using a crossover cable
•
Attached to an existing TCP/IP Ethernet network
•
As part of an independent network built with standard Ethernet hardware
•
Over a modem connection
•
(Wired+Wireless models only) In a wireless LAN
The networking method you use depends on several things, including whether you need control or data
acquisition, the number of PCs, controllers, and I/O units you are using, the speed and volume of
communication, security requirements, and the availability of an existing network.
Connecting the Controller Directly to a PC or Master Controller
A direct connection using a crossover cable connects just one SNAP PAC R-series controller with one host. A
direct connection is useful for assigning an IP address, configuring I/O points, and testing applications on I/O
units that will be used later on a network.
A direct connection is quick, easy to do, and provides high speed and high security for a small system. The
direct connection eliminates other variables that could interfere with communication, so you can focus on
maintenance and troubleshooting.
Crossover Cables
Use an Ethernet crossover cable for direct connections. The crossover cable must be a minimum of one meter
long. (Maximum length is 100 meters.) For reliability, we recommend you purchase the cable, rather than
build it.
If you build your own crossover cable, you’ll need an RJ-45 male connector at each end. The cable includes
four twisted pairs. Follow the illustration on the next page for wiring the connectors.
NOTE: The illustration on the next page shows both a
straight-through
cable and a
crossover
cable. The
straight-through cable is used for connecting the controller to a hub or switch on a standard Ethernet network. The
crossover cable is used for direct connection to a PC or other host.
If you’re not sure which cable you have, hold up both ends so the connector tab is at the back of each end. Compare
the color sequence of the wires in the connectors. If the sequence is identical for both connectors, it’s a
straight-through cable. If the sequence is different, it’s a crossover cable.
