Rockwell Automation Publication 1756-RM003N-EN-P - October 2011 611
ASCII String Instructions (CONCAT, DELETE, FIND, INSERT, MID) Chapter 18
Execution:
Example: To trigger a message in a MessageView terminal, the controller must send an ASCII string
that contains a message number and node number. String_1 contains the message
number. When add_node is set, the CONCAT instruction adds the characters in
node_num_ascii (node number) to the end of the characters in string_1 and then stores
the result in msg.
Relay Ladder
Structured Text
IF add_node THEN
CONCAT(string_1,node_num_ascii,msg);
add_node := 0;
END_IF;
Condition Relay Ladder Action Structured Text Action
Prescan The rung-condition-out is set to false. No action taken.
Rung-condition-in is false The rung-condition-out is set to false. N/A
Rung-condition-in is true The instruction executes.
The rung-condition-out is set to true.
N/A
EnableIn is set N/A EnableIn is always set.
The instruction executes.
Instruction execution The instruction concatenates the strings.
Postscan The rung-condition-out is set to false. No action taken.
add_node
String Concatenate
Source A string_1
'$1423\'
Source B node_num_ascii
'1'
Dest msg
'$1423\1'
CONCAT
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