Relay Ladder; Structured Text - Allen-Bradley Logix5000 Reference Manual

Execution:
Condition
Prescan
Rung-condition-in is false
Rung-condition-in is true
EnableIn is set
Instruction execution
Postscan
add_node
Relay Ladder Action
The rung-condition-out is set to false.
The rung-condition-out is set to false.
The instruction executes.
The rung-condition-out is set to true.
N/A
The instruction concatenates the strings.
The rung-condition-out is set to false.
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;
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
ASCII String Instructions (CONCAT, DELETE, FIND, INSERT, MID)
Structured Text Action
No action taken.
N/A
N/A
EnableIn is always set.
The instruction executes.
No action taken.
Chapter 18
CONCAT
String Concatenate
Source A string_1
'$1423\'
Source B node_num_ascii
'1'
Dest msg
'$1423\1'
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