Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 144)

Function of Control/Status Bits
Chapter 6
6Ć9
If the module detects an invalid I/O buffer split, it faults because of an
initialization error. The module disables its interface port and sets status
bit SW1(12).
Bit: IW3(03)
Function: Margin Justification
Description: Reset this bit to zero (default) for right justification, or set it
for left justification of data in data mode. The module ignores this bit
when operating in report generation mode.
You can select either right or left justification of data in data mode, only.
When operating in report generation mode, ASCII data is left justified.
BCD numbers included in the ASCII data string are right justified.
Justification refers to the positioning of string data in the data table when
the transferred string length is less than the set string length. It also refers
to the positioning of string data that is displayed by an ASCII device.
Refer to P. 3-7 for additional information on justification.
Bit: IW3(04)
Function: Sends End-of-String Delimiter to PC
Description: Set this bit when you want to send the end-of-string
delimiter to the processor for storage in the data table. Otherwise, reset
this bit to zero.
When generating single line messages, select the carriage return as the
end-of-string delimiter, set this bit, and set IW3(05), Output Line Feed if
Carriage Return.
Use this bit only in report generation mode. If the module detects that
you set this bit in data mode, the module defaults due to an initialization
error. The module disables its interface port and sets status bit SW1(12).
Bit: IW3(05)
Function: Output Line Feed If Carriage Return
Description: Reset this bit to zero (default) to inhibit this function. Set
this bit when you want line feed (LF) transmitted automatically whenever
the ASCII module transmits a carriage return (CR). Setting this bit saves
storing line feed control characters in the data table. You can use this bit
with IW3(04).
When generating multi-line messages, select some control code, such as
escape for the end-of-string delimiter, not carriage return. Set this bit,
IW3(05), but not IW3(04). Use the carriage return to terminate each line.