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TOF

Timer Off-Delay

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Timer block that, when energized, disables the output after a delay set by PT.

 

Ladder Representation

 

TOF_block

 

Block Structure

 

Variable Type

Name

Data Type

Description

VAR_INPUT

IN

BOOL

Block enabling

PT

WORD UINT

DWORD1 UDINT1

Delay of output deactivating

TIMEBASE

WORD

Time base for PT and ET

VAR_OUTPUT

Q

BOOL

Block output

ET

WORD UINT

DWORD1 UDINT1

Counter elapsed time

VAR

TOF_INST_0

TOF

Instance of access to block structure

 

wpshelp_common_fig_note

NOTE!

1. In CFW300 and CFW100, the PT and ET field types can only be WORD or UINT.

2. Some devices allow you to configure user parameters, but these need to be configured for use in the fields PT and ET, where it is necessary to select a compatible data type as shown in table above. For more information refer to the corresponding topic;

3) The TIMEBASE field may vary depending on the device used.

 

 

Operation

 

While the IN input is TRUE, the Q output is also TRUE and ET also receives the value zero.

On the negative transition edge in IN, counting is triggered and ET is incremented according to TIMEBASE. When ET equals PT, the Q output goes to state FALSE until IN revolutions to FALSE.

 

Compatibility

 

Device

Version

PLC300

1.50 or higher

SCA06

2.00 or higher

 

Block Flowchart

 

TOF_flowchart

 

Operation Diagram

 hardwaretimertof_fig2

 

Example in Ladder

 

TOF_example01

 

The above example disables the DO1 output to identify a low level in DI1 for 12 seconds, remaining disabled until DI1 again be TRUE.

 

Example in ST

 

 The example below displays the instructions for applying the example above in the ST language.

 

 

VAR

   PRESET : UINT := 12;

   ELAPSED : UDINT;

   TOF_INST_0 : FB_TOF;

END_VAR

 

TOF_INST_0.IN := DI1;

TOF_INST_0(PT:=PRESET, TIMEBASE:=2); // TIMEBASE according to

ELAPSED := TOF_INST_0.ET;           // the device used

DO1 := TOF_INST_0.Q;