String Delete (DELETE)

The DELETE instruction removes ASCII characters from a string.
The DELETE instruction deletes (removes) one or more characters from the Source and places the remaining characters in the Destination.
  • The Start position and Quantity define the characters to remove.
  • Unless Source A and the Destination are the same tag, Source A remains unchanged.
Available Languages
Ladder Diagram
Ladder Diagram_String Delete (DELETE)_v1
FactoryTalk Design Studio
 DSL - Ladder Diagram and Structured Text
DELETE(Source,Qty,Start,Dest);
Operands
There are data conversion rules for mixed data types within an instruction. See Data Conversion.
Ladder Diagram and Structured Text
Operand
Type
Format
Description
Notes
Source
String
Tag
The tag that contains the string from which you want to delete characters
String types are:
  • Pre-defined String data types:
    • STRING (82 characters)
    • STRING_32 (32 characters)
    • STRING_16 (16 characters)
  • Any custom, user-defined String data type you create with configurable length of characters for the string.
Quantity
SINT
INT
DINT
Immediate
Tag
The number of characters to delete
The Start plus the Quantity must be less than or equal to the length of the Source plus 1.
Start
SINT
INT
DINT
Immediate
Tag
The position of the first character to delete
Enter a number between 1 and the DATA size of the Source.
Destination
String
Tag
The tag to store the result
See Structured Text syntax Structured Text Syntax for more information on the syntax of expressions within structured text.
Affects Math Status Flags
No
Major/Minor Faults
A minor fault will occur if:
Fault Type
Fault Code
The LEN value of the Source string tag is greater than the DATA size of the Source string tag.
4
51
The length of output string is larger than the DATA size of the destination string tag.
4
52
The Start or Quantity value is invalid.
4
56
See Common Attributes for operand-related faults.
Execution
Ladder Diagram
Condition/State
Action
Prescan
N/A
Rung-condition-in is false
N/A
Rung-condition-in is true
The instruction executes.
Postscan
N/A
Examples
ASCII information from a terminal contains a header character. After the controller reads the data (term_read.EM is on), the DELETE instruction removes the header character. The controller can then use the text of the message or pass it on to another device
Structured Text
IF term_read.EM THEN
DELETE(term_input,1,1,term_text);
term_read.EM := 0;
END_IF;
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