Publication 1763-RM001C-EN-P - October 2009
312 ASCII Instructions
When the channel is configured for DF1 Full-Duplex protocol, the AWA
and AWT instructions only are valid and can transmit an ASCII string out
of the RS-232 port. If the RS-232 port is configured for any protocol other
than DFI Full-Duplex and ASCII, the AWA and AWT instructions will error
out with an error code of 9.
DF1 Full-Duplex packets take precedence over ASCII strings, so if an
AWA or AWT instruction is triggered while a DF1 Full-Duplex packet is
being transmitted, the ASCII instruction will error out with an error code
of 5.
See on page 505 for the DF1 Full-Duplex protocol parameters that you
set via the Channel 0 configuration screens in your programming
software. Configuration of the two append characters for the AWA
instruction can be found in the General tab of Channel Configuration
option in RSLogix 500.
String (ST) Data File
File Description
The string data file is used by the ASCII instructions to store ASCII
character data. The ASCII data can be accessed by the source and
destination operands in the ASCII instructions. The string data file can also
be used by the copy (COP) and move (MOV, MVM) instructions.
String files consist of 42-word elements. One string file element is shown
below. You can have up to 256 of these elements in the string file.
String Data File Structure
String Element
Bit 15141312111009080706050403020100
Word upper byte lower byte
0 String Length - number of characters (range is from 0 to 82)
1 character 0 character 1
2 character 2 character 3
↓↓ ↓
40 character 78 character 79
41 character 80 character 81
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