• Home
• Function/Function Block Reference
• IEC 61131-3 Functions and Function Blocks
• Character String
• LEFT

LEFT

Type	Function
Description	Extracts the leftmost characters of a string applied to IN. L specifies the number of characters to be extracted from IN.
Parameters	Inputs IN Data type: STRING Description: Input string. L Data type: ANY_INT Description: Number of characters to be extracted. Output OUT Data type: STRING Description: Output string.
Error behavior	Error behavior The following table shows the errors which may occur while executing the function and the value returned by the function in the corresponding error case. Error case Output value L < 0 Empty string '' L > len(IN) (len(...) = actual string length) Empty string '' Resulted string too short Empty string '' If any of the listed errors occurs, a string error is written to the Online log in the MESSAGES window. Note Controller stop on string error: The controller can be automatically stopped when a string error occurs. This allows you to locate the error in your project. To enable the automatic stop of the controller in case of a string error, activate the button in the Cockpit toolbar of the controller.
Additional information	EN/ENO behavior The POU is only executed if TRUE is applied to the EN input. If EN = FALSE, the POU is not executed and ENO = FALSE indicates the inactivity. If any of the errors listed under "Error behavior" occurs while executing the function, ENO is set to FALSE. Further Info See the topic "General information on execution control with EN/ENO" for further details.