Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 9)

Introduction
Chapter 1
1-5
A KF2 module provides either a point-to-point link or a multi-drop link
between an Allen-Bradley Data Highway and an intelligent asynchronous
device. By “intelligent asynchronous device” we mean any device that
complies with RS-232-C or RS-422-A electrical standards and that can be
programmed to handle the communication protocol described in
Chapters 4 through 6 of this manual. Throughout this manual, we will
also use the term “computer” in a general sense to refer to this type of
device. Some examples include:
An Allen-Bradley Advisor 2+ TM Color Graphic System
A PLC-3 Programmable Controller and Connected Communication
Adapter Module (Cat. No. 1775-KA)
A PLC-2 Family Programmable Controller and Connected PLC-2
Family/RS-232-C Interface Module (Cat. No. 1771-KG)
A PLC-4 Microtrol Programmable Controller and Connected
Communication Interface Module (Cat. No. 1773-KA)
A Variety of Minicomputers and Microcomputers
In point-to-point configuration, the KF2 module connects one intelligent
asynchronous device as a single station on a Data Highway. Figure 1.2
illustrates this configuration. Point-to-point links can use either peer-to-
peer (full-duplex) or master-slave (half-duplex) communication.
Figure 1.2
Point-to-Point Links
Computer
Modem
Modem
KF2 Module KF2 Module
Computer
KF2 Module
1771-KG
Module
PLC-2/30
Processor
11687
Allen–Bradley Longline
RS-232-C Link
(7,000 Cable-Ft. Max.)
Modem Link
Asynchronous Link
(50 Cable-Ft. Max.)
Data Highway Link
Data Highway Applications