Category: A-B

Communication Link

The 1747-DCM can physically reside on the RIO Link with any other adapter. It is

compatible with all RIO scanners.

1747-DCM Modules are connected in a daisy-chain configuration using

Belden™ 9463 cable. See the example below.

Extended Node Capability

The 1747-DCM features extended node capability. Extended node capability allows

you to have up to 32 adapters on the RIO link using an 82Ω termination resistor at

both ends of the RIO link for all baud rates.

IMPORTANT Extended node capability can only be used if the scanner and all

adapters on the RIO link have extended node capability.

System Overview

The Direct Communication Module, catalog number 1747-DCM, connects any

SLC 500 programmable controller with expansion chassis or SLC 500 Modular

Programmable Controller to a supervisory Allen-Bradley programmable controller

via the RIO Link, providing a distributed processing system. The 1747-DCM allows

these supervisory processors to transfer data between one another. The 1747-DCM

appears as an RIO adapter to:

• a PLC processor with integral RIO scanner on the RIO Communication Link

• an RIO scanner, catalog number 1771-SN or 1747-SN, on the RIO

Extended Node Capability

The 1747-DCM features extended node capability. Extended node capability allows

you to have up to 32 adapters on the RIO link using an 82Ω termination resistor at

both ends of the RIO link for all baud rates.

IMPORTANT Extended node capability can only be used if the scanner and all

adapters on the RIO link have extended node capability.

Switchover Conditions

The 1747-BSN module transfers control from the primary to the secondary

processor (switchover) if one of the following fault conditions occurs in the

primary system:

• power failure

• major fault in the processor

• 1747-BSN module fault

• primary processor mode change from Run to Program

Note: In order for switchover to occur, both primary and

secondary modules must be working without faults prior

to the event that triggers the switchover.

The 1747-BSN module provides backup functionality for the following:

• DH+ or RIO on a single pair of modules – Both may be backed up when two

or more pairs of modules are used.

• RS232 – Any RS232 device communicating with channel 0 of the SLC

controller may be backed up provided hardware-handshake lines are not

required. These ports only allow switchover of the transmit, receive and

ground wires for RS232.

Configuration Errors

The module reports the following configuration errors by flashing the fault LED:

• two 1747-BSN modules are configured with the same address

• LSL addresses are not consecutive (addresses must be numbered 0, 1, 2,etc.)

• last LSL switch is not set in the last module in the link

• last LSL switch is set in a module that is not the last in the link, or

• primary and secondary modules do not have the same configuration settings

(secondary module shows the configuration error)

Overview

The 1747-BSN Backup Scanner Module provides a high-speed communication

channel between two modular SLC 500™ (5/02 or higher) processors. The 1747-

BSN backup system uses a set of modules, with one or more 1747-BSN modules

residing in the primary system and one or more complementary modules in the

secondary or backup system. The primary system controls the operation of

remote I/O, while the secondary system monitors communications via the highspeed

serial link (HSSL) and is available to take over control in the event of a

fault in the primary system.

The backup scanner has the capability to switch between two communication

channels. The first channel is configurable as Remote I/O (RIO) or Data

Highway Plus™ (DH+). The second channel is used to switch one RS232/485

channel in order to provide connection for electronic operator interfaces.

A backup system using the 1747-BSN modules supports up to eight BSN

modules in each processor chassis, connected by a local status link (LSL). Only I/

O residing in remote chassis is backed up. Local I/O is not backed up. Examples

of RIO and DH+ system configurations are shown in Figures 1 and 2 on page 6.

Note: During the transfer of control from one processor to

another (switchover), the output modules in the remote

chassis maintain their last state until the secondary

processor program takes control. The secondary

processor program is not synchronized with the primary program.

• Link Response Time (RESP) – selects restricted or unrestricted RIO link

response time.

• Last Chassis/PLC-3 Backup (LAST CHA) – When the 1747-ASB module is

used with a PLC-2 or PLC-5, this switch indicates to the scanner that the

1747-ASB module is the last adapter mapped into the 1747-ASB module’s

highest logical rack. When using a PLC-3 processor, the switch determines

whether the 1747-ASB module supports the PLC-3 backup function.

• Addressing Mode (ADDR MODE) – determines the 1747-ASB module’s

remote chassis and remote expansion chassis addressing mode. 2-slot,

1-slot, and 1/2-slot are available.

• Specialty I/O Mode (SP MODE) – determines whether the 1747-ASB

module discretely maps or block transfer maps specialty I/O modules in its

remote chassis and remote expansion chassis.

• I/O Module Keying (KEY) – determines if the 1747-ASB module saves its

current I/O module and DIP switch configuration to its non-volatile memory,

or if the 1747-ASB module compares the current I/O module and DIP switch

configuration to the one saved in its non-volatile memory.

Configuration Parameters

The DIP switches allow you to configure the following items:

• Starting Logical Rack Number (Logical Rack) – is the 1747-ASB module’s

starting logical rack number in the scanner’s image.

• Starting Logical Group Number (Logical Group) – is the 1747-ASB

module’s starting logical group number within the scanner’s image.

• Baud Rate (Baud Rate) – is the 1747-ASB module’s RIO link communication

rate. The baud rate must be the same for all adapters on the RIO link.

• Primary/Complementary SLC Chassis (PRI/COMP) – determines

whether the 1747-ASB module appears to the scanner as a primary or

complementary chassis.

• Adapter Image Size (IMAGE SIZE) – indicates the I/O image size to be

reserved for the adapter. It can be any size between 2 and 32 groups in

2 logical group increments.

• Hold Last State (HLS) – determines whether the discrete output modules

are held in their last state when:

– RIO link communication with the 1747-ASB module is lost.

– The scanner inhibits the 1747-ASB module.

– The scanner sends Reset, Adapter Decide commands to the 1747-ASB module.

• Processor Restart Lockout (PRL) – determines whether the 1747-ASB

module automatically resumes RIO link communications if communication is

lost and then restored.

Slot Addressing

Slot Numbering

The 1747-ASB module is capable of controlling 30 slots. When expansion chassis

are used, the 1747-ASB module treats all of the I/O modules as if they are installed

in a single chassis.

The remote chassis and remote expansion chassis slots are numbered from 0 to 30.

The 1747-ASB module must reside in slot 0. Slots numbered 31 and above cannot

be used.

IMPORTANT Installing modules in slot 31 or above results in a module error.

Addressing I/O Modules

SLC and PLC processors address the I/O modules residing in the chassis by logical

rack and logical group. Slot addressing refers to how each chassis slot is assigned a

specific amount of the 1747-ASB module image. The amount depends on which

type of slot addressing you choose; 2-slot, 1-slot, and 1/2-slot addressing is

available, as shown below.

IMPORTANT Due to SLC and PLC addressing differences, when the 1747-ASB

module is used with an SLC processor, the image bit numbers are

0 to 7, 8 to 15 decimal. When the 1747-ASB module is used with

a PLC processor, the image bit numbers are 0 to 7, 10 to 17 octal.

Hardware Features

Required Tools and Equipment

Have the following tools and equipment ready:

• medium blade screwdriver

• (2) 1/2 watt terminating resistors (See page 18 for correct size.)

• an adequate length of RIO communication cable (Belden™ 9463) for your

specific application. (See page 18 for maximum cable distances.)

Determining System Power Requirements

Review the power requirements of your system to ensure that the chassis supports

placement of the 1747-ASB module. The adapter consumes 600 mA at 5V dc. For a

detailed list of device load currents, refer to the SLC 500 Fixed Hardware Style

Installation and Operation Manual, publication number 1747-6.21; the SLC 500

Modular Hardware Style User Manual, publication number 1747-UM011, or the

appropriate Technical Data sheet.

1747-ASB Module Overview

The 1747-ASB module is an SLC 500 single-slot, RIO communication link module. It

occupies the first slot (slot 0) of a 1746 remote chassis, where the SLC processor

normally resides.

The 1747-ASB module is an adapter, or slave, on the RIO link, and the master of the

remote chassis and remote expansion chassis in which it is installed. Remote

expansion chassis are optional. The module acts as a gateway between the scanner

and the I/O modules residing in the remote chassis and remote expansion chassis.

It maps the image of the I/O modules in its remote chassis and remote expansion

chassis directly to the SLC or PLC processor image.

Output data is sent from the scanner of either the SLC or PLC local chassis to the

1747-ASB module across the RIO link. This data is automatically transferred to the

output modules across the chassis backplane by the 1747-ASB module. Inputs from

the input modules are collected via the backplane by the 1747-ASB module and

sent back to the scanner across the RIO link. No user programming of the 1747-ASB

module is necessary.