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String instructions
LEFT
LEFT copies, starting from the left, n characters of the string of the first input variable to the output
Description
variable. You define the number of characters to be delivered n by the second input variable.
To add an enable input and enable output to the instruction, select [With EN/ENO] from the
"Instructions" pane (LD, FBD or IL editor). To reuse an instruction select "Recently used" from the
context menu or press <Ctrl>+<Shift>+<v> in the programming window.
Availability of LEFT (see page 1328)
PLC types
If the number of characters to be delivered is greater than the input
string, the complete string will be copied to the output variable
(output_string).
If the output string is longer than the length defined for the output
variable in the field "Type", only as many characters are copied from
the left as the output variable can hold. The special internal relay
R9009 (%MX0.900.9) is set.
The number of steps may vary depending on the PLC and parameters
used, see also Table of Code Intensive Instructions in the online help.
Data types
Data type
STRING
INT
STRING
Error flags
No.
IEC address
%MX0.900.7
R9007
%MX0.900.8
R9008
%MX0.900.9
R9009
In this example, the same POU header is used for all programming languages. For an example
Example
using IL (instruction list), please refer to the online help.
POU header
All input and output variables used for programming this function have been declared in the POU
header.
264
Copy characters from the left
I/O
Function
1st input
input string
2nd input
number of input string's characters that are copied, from the left
output
copied string
Set
permanently
for an instant
for an instant
If
input string is longer than the length
defined for the input variable in the field
"Type"
output string is longer than the length
defined for the output variable in the field
"Type"
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