Rockwell Automation Logix5000 Controllers ASCII Strings Programming Manual User Manual
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Chapter 1 Communicating with an ASCII device
Example:
When the temperature reaches the low limit (temp_low is on), the AWT instruction sends nine
characters from the string[2] tag to a MessageView terminal. (The $14 counts as one character. The
hex code for the Ctrl-T character.)
In the following example, you send a different number of characters each time and
want to automatically append one or two characters to the end of the data:
Example:
When alarm is on, the AWA instruction sends the characters in alarm_msg and appends a
termination character.
•
Because the number of characters in alarm_msg varies, the rung first moves the length of
alarm_msg (alarm_msg.LEN) to the length of the AWA instruction (alarm_write.LEN).
•
In alarm_msg, the $14 counts as one character. The hex code for the Ctrl-T character.
Send a different number of characters each time:
Example:
When MV_update is on, the AWT instruction sends the characters in MV_msg.
•
Because the number of characters in MV_msg varies, the rung first moves the length of MV_msg
(MV_msg.LEN) to the length of the AWT instruction (MV_write.LEN).
•
In MV_msg, the $16 counts as one character. The hex code for the Ctrl-V character.
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Rockwell Automation Publication 1756-PM013D-EN-P - October 2014