Specifications

Rockwell Automation Publication AG-SG001G-EN-P - April 2015 55
Choosing Data Communication Equipment Chapter 3
Choosing Dedicated Wire/
Power Line Modems
You can easily integrate dedicated wire/power line modems into your application.
You need a suitable dedicated wire pair or power line and an RS-232 interface.
The following table lists the recommended dedicated wire/power line modem
supplier and modem models. Consult the vendor for installation requirements
and detailed information about their product offerings.
Choosing a Cellular
Transmission System
Cellular modems are increasingly being used in SCADA applications to increase
productivity and uptimes. One of the key benefits of the cellular modem over
WLAN modems is that cellular modems are able to offer more network coverage
mobility. Being able to collect and distribute data without the limitation of
wireless hotspots or having a dedicated wired network using cellular network is
powerful. Typically a cellular modem is used when the network coverage
requirement is large and when use of satellites or other technology is not cost
effective. Cellular networks are predominantly offered as major technologies
namely, GSM (Global System for Mobile Communications) and CDMA (Code
Division Multiple Access). The GSM technology is more popular across different
countries while the CDMA is more popular in the U.S.
Cellular Network Architecture
The diagram below shows a typical cellular network layout.
Supplier Transmission Rate Topology Modem Model
DATA-LINC
Group
9600 bps Point-to-point
Point-to-multipoint
MDL500
(1)
(1) suitable for power line installations.
1200 bps Point-to-point
Point-to-multipoint
LLM1100
19200 bps Point-to-point DLM4000
Remote Site
Remote LAN/Devices
Gateway
Mobile Interface
gets IP address
from Cellular
Cellular IP
Network
Host Site (HQ)
Customer
WAN or