Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 8)

Chapter
2
2Ć1
Getting Started With Your ASCII Module
ASCII is the acronym for American Standard Code for Information
Interchange. The standard includes a 7-bit code for 128 data and control
characters.
With your ASCII I/O module you can transfer data, by means of the I/O
scan, from an ASCII device to the PC processor data table, and vice versa.
The module has two modes of operation, data mode and report generation
mode. In data mode, you can transfer ASCII, BCD, or hex characters.
Generally, use this mode to transfer data to the processor data table. In
report generation mode, you can include BCD values in the string of
ASCII characters. Generally, use this mode when you want to transfer
messages.
You can use your ASCII module with any Allen-Bradley programmable
controller that has an expandable data table, block transfer capability, and
uses the 1771 I/O structure. If you use a PLC-2/20 controller (cat. no.
1772-LP2), your programming will be lengthier because its processor
does not have file move or block transfer instructions.
Getting Started with Your ASCII Module is a hands-on exercise. By
going step by step through two easy examples, you will quickly learn
operation of your module’s basic features.
This chapter is divided into two sections, one for PLC-2 family
processors, the other for PLC-3 processors. Proceed to the section that
pertains to your processor.