Rockwell Automation Logix5000 Controllers ASCII Strings Programming Manual - Manual (Page 26)

Chapter 2 Processing ASCII characters
• The source is the same string tag as for the FIND instruction.
• The quantity values tells the MID instruction how many characters to pull
from the source.
• The start value is the same as the Result value from the FIND instruction.
This tells the MID instruction where to start pulling characters from the
Source.
• The Destination contains the characters you located.
The following example builds a string that contains two variables. For example, an
operator terminal may require a string that looks like the following:
• For more variables, use additional INSERT or CONCAT instructions.
• If you must send a floating-point value, use a RTOS instruction in place of
the DTOS instruction.
• The final string excludes the termination character. When you send the
string, use an AWA instruction to automatically append the termination
character.
Example: To trigger a message in a MessageView terminal, the controller sends the terminal a message in this
format: [Ctrl-T] message # \ address [CR]
Important: When send_msg is on, the rung does the following:
− The first DTOS instruction converts the message number to ASCII characters.
− The INSERT instruction inserts the message number (in ASCII) after the control character
[Ctrl-T]. (The hex code for Ctrl-T is $14.)
− The second DTOS instruction converts the node number of the terminal to ASCII characters.
− The CONCAT instruction puts the node number (in ASCII) after the backslash [ \ ] and stores
the final string in msg.
Important: To send the message, an AWA instruction sends the msg tag and appends the carriage return
[CR].
Build a string
26 Rockwell Automation Publication 1756-PM013D-EN-P - October 2014