TOF block
Short summary
Name |
|
→POU type |
|
Category |
|
Conform to →IEC-standard |
no restrictions, but: implementer-specific realization; see "Functionality" |
Graphical interface |
|
Available since |
version 1.4.1 (for Neuron Power Engineer) |
Functionality
This is an edge delay where the turning-off edge is delayed.
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). Output ET
returns the expired time since turning input IN
off, until the value entered at PT
is reached and as long as the input IN
is turned off.
Implementer-specific realization The IEC-standard does not specify whether and how to consider changes for input |
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 TOF
:
In-/outputs
|
Identifier |
Description |
|
---|---|---|---|
Inputs: |
|
|
input/start |
|
|
preset time |
|
Outputs: |
|
|
output |
|
|
elapsed time |
Input EN
and output ENO
are available when →calling the block. See "Execution control: EN, ENO" for information on input EN
and output ENO
.
See:
-
"Blocks for safe logic" whether this block is supported for developing safety-relevant applications.
-
"Highlighting safe logic in the FBD-editor" for the effects when using the block as a block for safe logic.
Example for usage within ST-editor
Simple call of TOF |
---|
|
Input EN
and output ENO
are available when →calling the block. See "Execution control: EN, ENO" for information on input EN
and output ENO
.
See:
-
"Blocks for safe logic" whether this block is supported for developing safety-relevant applications.
-
"Highlighting safe logic in the FBD-editor" for the effects when using the block as a block for safe logic.