BASIC and BASIC-T Modules

The modules are single-slot modules that reside in a SLC 500 fixed or modular controller chassis.

Use the module as:

• a foreign device interface.

• an operator interface.

Hardware Features

The module provides the following hardware features.

• 24 KB of battery backed RAM for storage of user programs and data

• Capacitive backup of RAM during battery change

• Socket for a standard 1747-M1, M2, M3, or M4 memory module 

(1746-BAS module) for nonvolatile storage of user programs

• Socket for a 1771-DBMEM1 or -DBMEM2 memory module 

(1746-BAS-T module) for nonvolatile storage of user programs

• Battery-backed, 24-hour clock/calendar

• Free-running clock with 5 ms resolution

• Two isolated 9-pin D-shell serial ports (PRT1 and PRT2) that 

provide RS-232/423, RS-422, and RS-485 communication with I/O devices

• One PRT2 port provides DF1 full-duplex or half-duplex slave 

protocol for SCADA applications

• One RJ-45 port (DH485) that provides communication over the DH485 network

• Multiple LED indicators for operator interface

• SLC 500 backplane interface

Overview

The module and the development software provide the following benefits.

• Easy data collection from user devices

• Integrated program debugging environment

• Operator interface capabilities

• Flexible program and data storage options

• High-level math

• Clock/calendar

• High-level programming environment

• Extensive online help system

• Easy access to editor functions through user interface

• Advanced text editor windows

TIP

The 1746-BAS-T module is a higher-speed version of 

the 1746-BAS module with identical hardware 

features. The modules can be interchanged, except 

that the 1746-BAS-T module uses different (optional) 

memory modules. Due to the high speed of the 

1746-BAS-T module, existing programs written for 

the 1746-BAS module may require adjustment for 

identical operation using the faster 1746-BAS-T module.

Description of the Application Example

This application example transfers up to 10 ASCII characters to the

SLC 5/03 processor. Each data packet less than 10 characters must

be terminated with a carriage return character (13 decimal) in order

to alert the BASIC module to transfer the data to the backplane. This

termination character may actually be any unique character. If you

require a different termination character, simply replace the “13” in

line 150 of the BASIC program with the decimal equivalent of the

new termination character.

Hardware and Software Configuration Information

N7:50 to N7:52 are the control words for the BTR function. N7:53

to N7:55 are the control words for the BTW function. For this

example, the following values must be placed in these words prior to

executing the ladder logic program:

• N7:50 – Must set bit 7 of this word to make it a BTR

• N7:51 – BT length, set to decimal 8

• N7:52 – RIO address (R, G, S), set to 100 decimal

• N7:53 – Must be sure bit 7 is a 0 to make it a BTW

• N7:54 – BT length, set to decimal 1 (only one word required to

transfer handshake bits).

• N7:55 – RIO address (R, G, S), set to 100 decimal

For this application example, the Remote I/O Adapter module is

configured as a logical rack 1, starting group 0,
logical rack size.

Also, 1-slot addressing and 57.6K baud is used.

Introduction

This application note demonstrates how to transfer ASCII data to an

SLC 5/02
or later processor by using a remote SLC 500 BASIC

module. An example shows how to transfer a maximum of 10

ASCII characters to an SLC 5/03 processor.

General Information

M-files cannot be accessed from a module in a remote I/O chassis.

Therefore, the BASIC module (Catalog Number 1746-BAS) is

limited to its 8 input and 8 output image words for data transfer

between itself and the SLC 5/02 or later processor. The first three

words of the I/O image are reserved for handshake bits, status, and

character count respectively. So, only 5 input and 5 output words are

available for actual data transfers. In addition, since a total of 8

words of image are used, they must be block transferred because

they do not fit in the image allocated in the Remote I/O Adapter

module (Catalog Number 1747-ASB).

To keep the BASIC programming to a minimum and the throughput

to a maximum, CALL 22 is used to transfer data from PRT1 on the

BASIC module to the SLC 5/03 processor in this case. CALL 22

operates on an interrupt basis, so the throughput of data from PRT1

to the backplane is 10 ms or less. To calculate overall throughput for

your specific system, consult your Remote I/O Adapter User Manual

(Publication 1747-6.13) and your Remote I/O Scanner User Manual

(Publication 1747-6.6).

If you also wish to transfer data from a SLC 5/02 or later processor

to a BASIC module in a remote I/O chassis, please refer to the

BASIC Language Reference Manual (Publication 1746-6.3) and

refer to the section on CALL 23.

Because of the variety of uses for this information, the user of and

those responsible for applying this information must satisfy

themselves as to the acceptability of each application and use of the

program. In no event will Allen-Bradley Company be responsible or

liable for indirect or consequential damages resulting from the use or

application of this information.

The illustrations, charts, and examples shown in this document are

intended solely to illustrate the principles of programmable

controllers and some of the methods used to apply them. Particularly

because of the many requirements associated with any particular

application, Allen-Bradley Company cannot assume responsibility or

liability for actual use based upon the illustrative uses and applications.

No patent liability is assumed by Allen-Bradley Company with

respect to use of information, circuits, equipment, or software

described in this text.

Reproduction of the contents of this document, in whole or in part,

without written permission of Allen-Bradley Company is prohibited.

System Module, Catalog Numbers 1715-AENTR, 1715-IB16D, 1715-OB8DE,

1715-IF16, 1715-OF8I Base Unit, Catalog Numbers 1715-A2A, 

1715-A3IO Termination Assembly, Catalog Numbers 1715-TASIB16D, 

1715-TADIB16D, 1715-TAS0B8DE, 1715-TADOB8DE, 1715-TASIF16, 

1715-TADIF16,  1715-TASOF8, 1715-TADOF8 Accessory, 

Catalog Numbers 1715-N2S, 1715-N2T, 1715-C2

Summary of Changes

This publication contains the following new or updated information. 

This list includes substantive updates only and is not intended to reflect  all changes. 

Rockwell Automation recognizes that some of the terms that are currently 

used in our industry and in this publication are not in alignment  

with the movement toward inclusive language in technology. 

We are proactively collaborating with industry peers to find alternatives to such  

terms and making changes to our products and content. 

Please excuse the use of such terms in our content while we implement these  changes.

Conformal Coating Standards 

The 1715 modules are conformally coated and meet the following standards: 

• ANSI/ISA-S71.04-2013; Class G1, G2, and G3 environments 

• CEI IEC 60654-4:1987; Class 1, 2, and 3 Environments

• UL746E 

• MIL-1-46058C to ASTM-G21 (Tropicalization and fungicide)