Short summary

Name	`uTOF`
→POU type	→function block
Category	IEC-block, TimerEnh
Conform to →IEC-standard	not defined in IEC-standard
Graphical interface
Available since	version 1.45.0 (for logi.CAD 3)

Functionality

Similar to the TOF block, this is an edge delay where the turning-off edge is delayed. In contrast to TOF, the output ET is not provided for uTOF.

Enter the delay period at input PT. If input IN is →turned on, output Q returns value TRUE (or an equivalent). If input IN is →turned off and the delay period is over, output Q returns FALSE (or an equivalent). If input PT is changed after input IN has been turned off, the behavior of the block is affected.

This block receives the current system time from the runtime system. This time remains constant while the same task is executed. However, in case of different tasks, it is possible that a different system time is used when the belonging programs are executed (even if the different tasks have the same cycle time).

The following illustration shows the behavior of uTOF:

images/download/attachments/414782886/uTOF-version-1-modificationdate-1535106254151-api-v2.png

In-/outputs

	Identifier	→Data type	Description
Inputs:	`IN`	`BOOL`	input/start
Inputs:	`PT`	`TIME`	preset time
Outputs:	`Q`	`BOOL`	output

Input EN and output ENO are available when →calling the block. See "Execution control: EN, ENO" for information on input EN and output ENO.

Example for usage within ST-editor

Simple call of uTOF

PROGRAM Test
    VAR
        utof1     : uTOF;
        elapsed   : BOOL := TRUE;
        help      : BOOL := TRUE;
    END_VAR
    utof1(IN := help, PT := T#2s, Q => elapsed);
    (* Instance of block 'uTOF' is called. Variable 'elapsed' is set to FALSE after 2 seconds, right after you set 'help' to FALSE . *)
END_PROGRAM

When creating your application within the ST-editor, enter a call of a block by typing the text as requested by the syntax or use Content Assist.