634 Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 19 ASCII Conversion Instructions (STOD, STOR, DTOS, RTOS, UPPER, LOWER)
Example: To find information about a specific item, an operator enters the item number
into an ASCII terminal. After the controller reads the input from a terminal
(terminal_read.EM is set), the LOWER instruction converts the characters in
item_number to all lower case characters and stores the result in
item_number_lower_case. A subsequent rung then searches an array for characters
that match those in item_number_lower_case.
Relay Ladder
Structured Text
IF terminal_read.EM THEN
LOWER(item_number,item_number_lower_case);
terminal_read.EM := 0;
END_IF;