Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 56)

Choosing Module Features
Chapter 3
3Ć14
Choosing Data Conversion, IW2(14Ć16)
Data conversion refers to the number and type of characteers that you
store in a data table. word. The selections of data conversion from which
you choose depend on the mode of module operation (Table 2.G).
Table 2.G
Data Conversion
When In Select One Using Code
Data mode, you must select one type of data
conversion (quantity and type of characters
per word). To change data conversion, you
must reinitialize the module.
2 ASCII/word
3 BCD/word
4 BCD/word
1 ASCII/word
4 Hex/word
000
001
010
011
100
Report generation mode, your text is 2 ASCII
characters per word. You must select either 3
BCD or 4 BCD characters per word for your
BCD values within your text.
3 BCD/word
4 BCD/word
001
010
Record your selection based on your choice of module operation by
writing the code in IW2(14-16) using the form (found at the end of this
chapter) or the boxes below.
IW2
Data
Conversion
16 15 14
A BCD delimiter is a character that you place before and after BCD
values. It tells the ASCII module to interpret the values as BCD, not as
ASCII for conversion.
In report generation mode when using BCD values with ASCII data
characters, you must separate BCD values by means of a delimiter. For
example, if you want to use the BCD value of 297 in a message and you
have selected the asterisk (0101010 in binary or 2A in hex) as the BCD
delimiter, you would place the asterisk before and after the BCD value,
*297*. Otherwise, the 7-bit ASCII equivalent of BCD 297 would be
transferred as unwanted characters.
Using BCD Delimiters (Report
Generation Mode, Only),
IW4(10Ć16)