Rockwell Automation Logix5000 Controllers ASCII Strings Programming Manual - Manual (Page 13)

Communicating with an ASCII device Chapter 1
• If the ASCII device is configured for XON/XOFF flow control, select
the XON/XOFF check box.
• If the ASCII device is a CRT or pre-configured for half duplex
transmission, select the Echo Mode check box.
• Choose the Delete Mode using the following considerations:
If the ASCII device is Select Tips
CRT CRT • The DEL character ($7F) and the character that precedes the DEL character are not sent to
the destination.
• If echo mode is selected and an ASCII instruction reads the DEL character, the echo returns
three characters: BACKSPACE SPACE BACKSPACE ( $08 $20 $08).
Printer Printer • The DEL character ($7F) and the character that precedes the DEL character are not sent to
the destination.
• If echo mode is selected and an ASCII instruction reads the DEL character, the echo returns
two characters: / ($2F) followed by the character that was deleted.
None of the above Ignore The DEL character ($7F) is treated as any other character.
2. Click OK.
Store ASCII characters in tags that use a string data type.
You can use the default STRING data
type. It stores up to 82 characters. or You can create a string data type to store the
number of characters that you define.
Important: Use caution when you create a string data type. If you decide later to change the size of the
string data type, you may lose data in any tags that currently use that data type.
If you Then
Make a string data type smaller • The data truncates.
• The LEN does not change.
Make a string data type larger The data and LEN resets to zero.
Create string data types
Rockwell Automation Publication 1756-PM013D-EN-P - October 2014 13