
Chapter 2
Processing ASCII characters
You can process ASCII characters to do many things, including:
• Interpret a bar code and take action based on the bar code.
• Use a weight from a weigh scale when the weight is sent as ASCII
characters.
• Decode a message from an ASCII triggered device, such as an operator
terminal.
• Build a string for an ASCII triggered device using variables from your
application.
For example, a bar code may contain information about a bag on a conveyor at an
airport. To check the flight number and destination of the bag, you extract
characters 10 - 18.
Airline Origin Flight # Destination Date
Bar code N W A
H O P
5 0 5 8
A M S
0 2 2 2 0 1
Character number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
5 0 5 8
A M S
9 characters
Example:
In the baggage handling conveyor of an airport, each bag gets a bar code. Characters 10 - 18 of the
bar code are the flight number and destination airport of the bag. After the bar code is read
(bag_read.EM is on) the MID instruction copies the flight number and destination airport to the
bag_flt_and_dest tag.
Extract a part of a Bar Code
Rockwell Automation Publication 1756-PM013D-EN-P - October 2014 19
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