Allen-Bradley 1771-KRF/B User manual

Allen-Bradley
Broadband Communication
Interface
(Cat. No. 1771-KRF/B)
User’s Manual

Preface I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Purpose of this Manual I . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audience
II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Precautions
II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vocabulary
II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Related Products
III . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Related
Publications III . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Product Overview 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Objectives 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
What is the 1771KRF? 11
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How the KRF Operates on Broadband 12
. . . . . . . . . . . . . . . . . . . . .
Compatible Devices 14
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Guidelines for Connecting the 1771KRF 21. . . . . . . . . . . . . .
Chapter Objectives 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Highway and Data Highway Plus Networks 21
. . . . . . . . . . . . . .
Remote
I/O Networks 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Network
Guidelines 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical
Applications 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting Channels and Setting Switches 31. . . . . . . . . . . . .
Chapter Objectives 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Available Channels for 1771KRF Module 31
. . . . . . . . . . . . . . . . . .
Setting
the Option Switches 32. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing and Connecting the 1771KRF 41. . . . . . . . . . . . . .
Chapter Objectives 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mounting the KRF 41
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting
the KRF to DH/DH+ or Remote I/O Modules 42. . . . . . . .
Connecting the 1771KRF to the Broadband Cable System 49
. . . . . .
Powering Up the 1771KRF 411
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting the Network with the LEDs 411
. . . . . . . . . . . . . . . . .
Specifications A1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Using the 1771KRF with 6608 Modems B1. . . . . . . . . . . . . . .
Table of Contents

Preface
I
Preface
This manual shows you how to use the 1771-KRF/B Broadband
Communications Interface. It provides information on:
Configuring the DH/DH+ or remote I/O networks using the
1771-KRF/B
Installing the KRF/B
Troubleshooting the KRF/B
WARNING: This equipment generates, uses, and can radiate
radio frequency energy, and if not installed and used in
accordance with this document, may cause interference with
radio communications. It has been tested and complies with the
limits for class A computing device pursuant to Subpart J of
Part 15 of FCC rules, which provide reasonable protection
against such interference when operating in a commercial
environment. Operation of this equipment in a residential area
is likely to cause interference in which case the user will take
appropriate measures to correct.
This digital apparatus does not exceed the Class A limits for
radio noise emissions from digital apparatus set out in the Radio
Interference Regulations of the Canadian Department of
Communications.
The Purpose of this Manual

Preface
II
You should read this manual before attempting to install the 1771-KRF/B.
We assume you are already familiar with the following Allen-Bradley
devices:
Programmable Logic Controllers (PLCs)
Data Highway and Data Highway Plus networks
Remote I/O networks
Data Highway and Data Highway Plus communication device(s) you
are using to communicate through the 1771-KRF/B
If you are not, refer to the appropriate documentation before you begin.
For a list of related publications, see page III.
The following conventions are used in this manual:
This statement Means this
Important points out specific areas of concern
CAUTION damage to equipment could occur
WARNING personal injury could occur
In this document we refer to the:
1771-KRF/B module as the “KRF” or “KRF module”
Data Highway and Data Highway Plus networks as “DH/DH+”
networks
Audience
Safety Precautions
Vocabulary

Preface
III
Allen-Bradley offers a wide range of interfaces for DH/DH+ and remote
I/O networks, including:
For this Product Order this Catalog
Number
DH/DH+ Asynchronous (RS232C or RS422A) Interface
Module (Desk T op)
1770KF2
DH PLC2 Family Communication Adapter Module 1771KA2
DH RS232C Interface Module 1771KE/KF
DH PLC3 Communication Adapter Module 1775KA
DH+ to DH Interface Module 1785KA
DH+ PLC2 Family Communication Adapter Module 1785KA3
DH+ RS232C Interface Module (Rack Mount) 1785KE
PLC5 Family Programmable Controllers Series 1785L T
DH/DH+ PLC3 Communication Adapter 1775S5
PLC2 Scanner 1772SD2
Remote I/O Adapter Module 1771ASB
Important: Be certain you have the Series 6600 single channel translator
with the correct channel before you begin. You must have this component
to operate the 1771-KRF. Refer to table 3.A for a list of available
channels.
For more information on DH/DH+ and remote I/O networks and channel
translators, refer to these publications:
Title Publication Number
Data Highway Overview Product Data 17702.39
Data Highway Plus Overview Product Data 17852.6
Channel T ranslators Product Data 66002.4
Data Highway Cable Assembly and Installation Manual 17706.2.1
Remote I/O Adapter Module Product Data 17712.48
PLC5 Family Processor Assembly and Installation Manual 17856.6.1
PLC3 Family Controller Programming Reference Manual 17756.4.1
MiniPLC2/02, 2/16, 2/17 Processor User ' s Manual 17726.5.8
Remote I/O Adapter Installation Data 17712.162
These publications are available from Allen-Bradley. Contact your local
Allen-Bradley sales office for more information.
Related Products
Related Publications

Chapter 1
11
Product Overview
In this chapter, you will read about:
what the 1771-KRF is
how the KRF operates on broadband
compatible devices
The KRF is a module that lets DH, DH+, and remote I/O stations
communicate over a broadband cable system. Figure 1.1 shows the KRF’s
hardware features:
Figure 1.1
1771KRF
hardware features
XMTG
RCVG
FAULT
2
SH
1
BROADBAND
1771–KRF
Diagnostic
Indicators
(see page 4 - 11)
Connector for
Data Highway,
Data Highway Plus or Remote I/O
module
(see page 4 - 3)
Broadband
F" connector
(see page 4 - 10)
17270
Chapter Objectives
What is the 1771KRF?

Product Overview
Chapter 1
12
A broadband communication system is an alternative way to connect
communication equipment. Numerous separate networks share a single
coaxial cable, eliminating separate wires for each network. Broadband
cable systems use the same type of cable used in Community Access
Television (CATV), which can cover large distances using standard CATV
devices. Its high level of noise immunity is well suited to the industrial
environment, since communication takes place at RF frequencies well
above motor noise, arc welder noise, and AC noise.
Imagine the broadband cable system as a tree-like structure that has
several trunks and various branches with taps. When the system is
expanded, new devices are tapped in to the branches. Further expansions
can be made by adding branches.
tap
branch
trunk
expansion
Just as CATV provides users with multiple channels on one cable,
broadband systems provide multiple data channels using RF technology to
divide the bandwidth of the cable into separate frequency bands. In data
systems, the frequency space that one CATV channel occupies is often
divided into many subchannels that offer separate services. Data
communication on CATV systems use channel pairs for two-way
communication. Each separate network occupies its own pair of channels
or subchannels. A message from a device on the cable is transmitted on
an inbound channel to a central location called the headend. Here, a
translator device transfers the message to an outbound channel that
broadcasts it to all devices that receive the channel. In this way, a data
channel replaces a daisy-chained twisted pair cable connection.
How the KRF Operates on
Broadband

Product Overview
Chapter 1
13
The KRF module takes the signals from the DH/DH+ or remote I/O
module as input and transmits them on the broadband cable. This allows
the DH/DH+ and remote I/O protocol to be transmitted directly over the
broadband link, creating a communication link on a broadband cable
instead of on the traditional twinaxial baseband cable. The
communication rate over the DH/DH+ or remote I/O link is 57.6 or
115.2K baud. The baud rate you use depends on the modules you are
using.
The KRF acts as a companion module to each DH/DH+ or remote I/O
module on the broadband. You need one KRF for each DH/DH+ or
remote I/O module that communicates over the broadband. The KRF’s
industrialized, single–slot, 1771 form factor design lets you install it in
any 1771- I/O chassis.
You connect the KRF to the DH/DH+ or remote I/O module with a length
(up to 100 ft) of twinaxial baseband cable. Connect the KRF to broadband
with a standard broadband drop cable.
The KRF is frequency agile over 18 subchannel pairs, which allows 1-18
DH/DH+ or remote I/O links to operate directly on a single broadband
cable system.
The table below shows the possible interfaces for broadband alone and
with the KRF module. A single cable system could carry all of these
services in addition to closed circuit TV security systems, satellite
distribution channels and more to create a total facility communication
system.
Table 1.A
Broadband/KRF
Possible Interfaces
Ethernet Arcnet MAP DH DH+ Remote I/O
Broadband X X X
Broadband + KRF X X X X X X

Product Overview
Chapter 1
14
The following Allen-Bradley devices have been tested and qualified with
the 1771-KRF:
Table 1.B
1771KRF
Qualified Modules
Module Compatible Devices
Data Highway
1785KA (Data Highway port)
1771KE/KF
1771KA2
1774KA
1770KF2
1775KA
Data Highway Plus
PLC5/12
PLC5/15
PLC5/25
1784KTK1
1784KT
1785KE
1770KF2
1785KA3
1785KA (Data Highway Plus port)
Remote I/O Scanners
1775S5
1775S4B
1775S4A
5150RS
1772SD2
Series 1784L T
Remote I/O Adapters
1771ASB
1771NA (used in the T 30 terminal and the 2705 Ready Panel)
Series 1784L T
1771ASC
1771DCM
Important: The 1771-KRF has been qualified with the above DH/DH+
and remote I/O modules on a broadband cable system with a radius
Compatible Devices

Product Overview
Chapter 1
15
(distance from headend to furthest KRF) of four miles. If your
application exceeds this distance, contact your local Allen-Bradley
representative for assistance.
Allen-Bradley will continue to test additional DH/DH+ and remote I/O
interfaces and will update you as testing is completed.
If you have any further questions about devices you wish to interface to
the 1771-KRF, contact your local Allen-Bradley representative.

Chapter 2
21
Guidelines for Connecting the 1771KRF
This chapter contains the following:
what DH/DH+ networks are
what a remote I/O network is
network guidelines
typical applications using the KRF
Data Highway and Data Highway Plus are local area networks that allow
peer-to-peer communication between PLCs, computers, and other
intelligent devices:
Data Highway
DH connects up to 64 nodes and has a communication rate of 57.6K baud.
It implements peer-to-peer communication through a modified
token-passing scheme called floating master. In this arrangement, each
node has equal access to be master. The nodes bid for temporary
mastership based on their need to send information. Fault recovery
timeouts are used if mastership token is lost.
Data Highway Plus
DH+ connects up to 64 nodes and has a communication rate of 57.6 or
115.2K baud. It implements peer-to-peer communication with a
token-passing scheme to rotate link mastership among its nodes. DH+
also uses timeouts to recover from a fault that disables the node that has
the token. Use a DH+ link when you want to connect a small number of
nodes that communicate frequently on a common link. For example, you
would use DH+ to connect a small group of PLC-5s (usually 10 or less)
involved in a single integrated process.
Chapter Objectives
Data Highway and Data Highway
Plus Networks

Guidelines for Connecting the 1771KRF
Chapter 2
22
A remote input and output (remote I/O) network is a local area network
that supplies PLCs with digital and/or digitally encoded plant floor
information.
Remote I/O modules reside at some location other than the chassis that
contains the master PLC processor. Local I/O modules reside in the same
chassis as the master PLC processor. A chassis of remote I/O modules is
electrically connected to the devices it controls on the plant floor.
Remote and local I/O can consist of digital or digitally encoded analog
values.
You can configure PLC processors as master devices that scan adapter, or
slave devices. Slave devices monitor the I/O data and provide
information requested by the master PLC processor via block transfer
commands. This I/O information is used in the PLC ladder logic program
to control a process. The KRF module allows remote I/O information to
be transferred onto the broadband cable system, which increases the
physical distance between local PLC networks and remote I/O modules.
Remote I/O Networks

Guidelines for Connecting the 1771KRF
Chapter 2
23
Use the following guidelines when you want to add a DH/DH+ or remote
I/O network to your broadband system:
You need a channel translator (use the Allen-Bradley 6600 channel
translator) at the head-end of the broadband cable system
The 1771-KRF has been tested with a wide variety of DH/DH+
interface modules. Before installing the 1771-KRF, refer to the page
1-4 to verify that it has been tested with the DH/DH+ or remote I/O
module you intend to use
Configure all KRFs that connect devices on a common network or
subnetwork for the same channel pair
The KRF operates on a cable system that meets the requirements of the
MAP/TOP or IEEE 802.7 broadband media specification
To determine the maximum allowable distance for your application
from the KRF DH/DH+ or remote I/O module to the headend
translator, see page 1-4
You need one KRF module for each DH/DH+ or remote I/O port you
connect to the broadband
The baseband twinaxial cable between the DH/DH+ or remote I/O port
and the KRF should be as short as possible. The maximum length for
this cable is 100 ft
The maximum number of nodes allowed on the DH/DH+ broadband
link is 64
The communication rate over the DH/DH+ or remote I/O link is 57.6
or 115.2K baud. The baud rate you use depends on the modules you
connect to and their configurations
The maximum number of nodes on a remote I/O link depends on the
processor type (See the appropriate user’s manual for details)
Important: The 1771-KRF acts as a modem to connect individual
DH/DH+ or remote I/O stations to a broadband DH/DH+ or remote I/O
network. Do not connect more than one DH/DH+ or remote I/O device to
the twinaxial cable of the KRF.
This section contains four typical applications for the KRF involving:
a single DH broadband link
a single DH+ broadband link
a DH broadband backbone linking DH+ twinaxial baseband
subnetworks
a single remote I/O broadband link
It shows you how these networks are configured and explains the benefits
of each.
Network Guidelines
Typical Applications

Guidelines for Connecting the 1771KRF
Chapter 2
24
Data Highway on Broadband Configuration
Broadband cable and modems replace daisy-chained twinaxial media and
offer a greater distance between nodes, as well as multiple networks
coexisting on one cable. Figure 2.1 shows a typical DH on broadband link
configuration where KRFs create a single DH broadband link.
Figure 2.1
Typical
DH on broadband configuration
VAX or any
asynchronous
host Advisor PC
1770KF2 1771KE
KRF KRF
KRF KRF KRF KRF
PLC2
1771KA2
PLC2
1771KA2
PLC3
1775KA PLC3
1775KA
Translator
RS232
baseband cable 100 ft max.
Data Highway on broadband
17271
Table 2.A contains more information about figure 2.1:
Table 2.A
Configuring
a single DH link on the broadband network
These Devices Connect this to the Data
Highway Broadband Cable Link
KRFs + 1771KA2 Communication Adapter
Modules
PLC2s
KRFs + 1775KA Communication Adapter
Modules
PLC3s
KRFs + 1771KE/KF DH/RS232 Communication
Controller Modules
host computers
KRFs + 1770KF2 DH/RS232 Communication
Interface Module
host computers

Guidelines for Connecting the 1771KRF
Chapter 2
25
Data Highway Plus on Broadband Configuration
Broadband cable and modems now replace daisy-chained twinaxial media
and offer a greater distance between nodes as well as multiple networks
coexisting on one cable. Figure 2.2 shows a typical DH+ on broadband
configuration where KRFs create a single DH+ link.
Figure 2.2
DH+
on broadband configuration
KRF KRF KRF KRF
PLC2
1785KA3 PLC5
Advisor PC
1785KE
KRF
VAX or any
asynchronous
host
1770KF2
KRF
Translator
KRF
T50
Data Highway Plus on broadband
100 ft max
RS232
baseband cable
PLC2
1785KA3 PLC5
1784KT
17272
Table 2.B explains the configuration in figure 2.2:
Table 2.B
Configuring
a single DH+ link on the broadband network
These Devices Connect this to the DH+
Broadband Link
KRFs + 1784KT Communication Adapter
Modules
T 50s, T/35s, IBM A T/XT and
compatible computers
KRFs + 1785KA3 Communication Adapter
Modules
PLC2s
KRFs + builtin DH+ port of the PLC5 PLC5s
KRFs + 1785KE DH/RS232 Communication
Controller Modules
host computers
KRFs + 1770KF2 DH/RS232 Communication
Interface Module
host computers

Guidelines for Connecting the 1771KRF
Chapter 2
26
Data Highway Broadband Backbone/Data Highway Plus Subnet
Configuration
Broadband cable and modems now replace daisy-chained twinaxial media
and offer a greater distance between nodes as well as multiple networks
coexisting on one cable. The 1785-KA is typically used to link DH+
baseband subnetworks over a DH backbone. This lets you increase the
number of DH+ nodes that can share information without lowering
throughput within subnetworks. Figure 2.3 shows the DH backbone/DH+
subnet configuration where KRFs create a DH broadband backbone.
Figure 2.3
DH
broadband/DH+ subnet configuration
VAX or any
asynchronous
host
1770KF2
KRF
RS232
Advisor PC
1771KE
KRF
100 ft max
Translator
KRF KRF
baseband cable
RS232
1785KA 1785KA
PLC3
1775S5 PLC2
1785KA3 PLC5 T50
PLC2
1785KA3
PLC3
1775S5 PLC5
baseband
Data Highway Plus
baseband
Data Highway Plus
17273
Data Highway on broadband
1784KT
Configure the network as follows:
Data Highway Plus twinaxial baseband subnetworks are linked to the
broadband backbone via KRFs attached to the Data Highway port of
the 1785-KA DH/DH+ Communication Adapter modules
KRFs are used with 1770-KF2 and 1771-KE DH/RS-232
Communication Controller modules to connect host computers to the
Data Highway broadband backbone

Guidelines for Connecting the 1771KRF
Chapter 2
27
We recommend this configuration to optimize overall system performance
by minimizing the number of nodes on each of the DH+ subnetworks.
This configuration also optimizes overall system performance by isolating
local traffic to the individual DH+ subnetworks. The DH protocol is used
on the broadband backbone.
See the 1785-KA DH/DH+ Communication Adapter Module manual
(publication 1785-6.5.1) for more details on this application. The manual
contains examples of DH baseband applications that are valid for
corresponding DH on broadband applications using the KRF.
Remote I/O Broadband Link Configuration
In this application, the KRF and standard remote I/O modules create a
single remote I/O link that resides directly on the broadband. The block
transfer read and write scanning of remote I/O is sent over the broadband.
Figures 2.4, 2.5, and 2.6 show possible remote I/O broadband link
configurations for PLC-5, PLC-3, and PLC-2 programmable controllers.
Table 2.C on page 2-9 tells you what scanner or adapter you need to
configure the network in each example.
Figure 2.4
Remote
I/O on broadband link using the PLC5 Programmable Controller
PLC5
KRF
KRF KRF KRF KRF
1771ASB 1771ASB 1771ASB 1771ASB
Translator broadband
baseband cable
remote I/O on
17883

Guidelines for Connecting the 1771KRF
Chapter 2
28
Figure 2.5
Remote I/O on broadband link using the PLC2 Programmable Controller
PLC2
KRF
KRF KRF KRF KRF
1771ASB 1771ASB 1771ASB 1771ASB
Translator
baseband cable
1771SD2
broadbandremote I/O on
17884
Figure 2.6
Remote I/O broadband link using the PLC3 Programmable Controller
PLC3
KRF
KRF KRF KRF KRF
1771ASB 1771ASB 1771ASB 1771ASB
Translator
baseband cable
1775S5
broadbandremote I/O on
17885
Table 2.C lists the devices you use to connect each programmable
controller to the remote I/O broadband link.

Guidelines for Connecting the 1771KRF
Chapter 2
29
Table 2.C
1771KRF
Configurations for PLC5, PLC3, and PLC2 Programmable Controllers
Use these devices T o connect these devices to the
remote I/O broadband link
1771KRF and builtin remote I/O port of
the PLC5
PLC5
1771KRF and 1771ASB adapter I/O chassis
1771KRF and 1772SD2 scanner PLC2
1771KRF and 1775S5 scanner PLC3

Chapter 3
31
Selecting Channels and Setting Switches
In this chapter, you read about:
available channels for the KRF
setting the option switches on the KRF
The KRF module is frequency agile, which means you can change the
operating subchannel as your application requires. The KRF operates on
these standard CATV channel pairs:
T12/L
T13/M
T14/N
Table 3.A shows the frequencies for each channel pair:
Table 3.A
KRF
channel pair frequencies
Channel Pair
T ransmit (MHz) Receive (MHz)
T12 to L 35.75 to 41.75 228 to 234
T13 to M 41.75 to 47.75 234 to 240
T14 to N 47.75 to 53.75 240 to 246
Chapter Objectives
Available Channels for 1771KRF
Module