Execution of TIMER-type Event Processing

Description

TIMER-type event processing is any process triggered by the ITCNTRL function.

This timer function periodically activates event processing every time the preset value is reached.

Reference

The following parameters are selected in the event processing properties.

Parameter	Value	Default value	Role
Time base	1 ms, 10ms, 100ms, 1 sec	10ms	Timer time base. Note: the time base of 1ms should be used with care, as there is a risk of overrun if the processing triggering frequency is too high.
Preset	1..1023	10	Timer preset value. The time period obtained equals: Preset x Time Base.
Phase	0..1023	0	The value of the temporal offset between the STOP/RUN transition of the PLC and the first restart of the timer from 0. The temporal value equals: Phase x Time Base.

Parameter

Value

Default value

Role

Time base

1 ms, 10ms, 100ms, 1 sec

10ms

Timer time base. Note: the time base of 1ms should be used with care, as there is a risk of overrun if the processing triggering frequency is too high.

Preset

1..1023

10

Timer preset value. The time period obtained equals: Preset x Time Base.

Phase

0..1023

0

The value of the temporal offset between the STOP/RUN transition of the PLC and the first restart of the timer from 0.

The temporal value equals:

Phase x Time Base.

NOTE: The Phase must be lower than Preset in TIMER-type Event.

ITCNTRL Function

The following table describes the input parameters:

Parameter	Type	Comment
`Enable`	BOOL	Enable input selected
`Reset_Timer`	BOOL	At 1 resets the timer
`Hold_Timer`	BOOL	At 1, freezes timer incrementation.
`Nb_Task_Event`	BYTE	Input byte which determines the event processing number to be triggered.

The following table describes the output parameters:

Parameter	Type	Comment
`Status_Timer`	WORD	Status word.
`Current_Value`	TIME	Current value of timer.

Timing Diagram for Normal Operation

Normal operation

The following table describes the triggering of TIMER-type event processing operations (see timing diagram above).

Phase	Description
1	When a rising edge is received on the `RESET` input, the timer is reset to 0.
2	The current value `VALUE` of the timer increases from 0 towards the preset value at a rate of one unit for each pulse of the time base.
3	An event is generated when the current value has reached the preset value, the timer is reset to 0, and then reactivated. The associated event processing is also triggered, if the event is not masked. It can be deferred if an event processing task with a higher or identical priority is already in progress.
4	When the `ENABLE` input is at 0, the events are no longer sent out. TIMER type event processing is no longer triggered.
5	When the `HOLD` input is at 1, the timer is frozen, and the current value stops incrementing, until this input returns to 0.

Event Processing Synchronization

The Phase parameter is used to trigger different TIMER-type event processing tasks at constant time intervals.

This parameter set a temporal offset value with an absolute time origin, which is the last passage of the PLC from STOP to RUN.

Operating condition:

The event processing tasks must have the same time base and preset values.
The RESET and HOLD inputs must not be set to 1.

Example: Two event processing tasks Timer1 and Timer2 to be executed at 70ms interval.

Timer1 can be defined with a phase equal to 0 and the second Timer2 with a phase of 70ms (phase of 7 and time base of 10ms).

Any event triggered by the timer associated with the Timer1 processing task shall be followed after an interval of 70ms by an event from the timer associated with the Timer2 processing task

Timing Diagram: STOP/RUN Transition

Operation After PLC STOP/RUN

The following table describes the operation of the PLC after a transition from STOP into RUN (see timing diagram above):

Phase	Description
1	ON a STOP RUN transition of the PLC, timing is triggered so that the preset value is reached at the end of a time period equal to Phase x time base, when the first event is sent out.
2	The current value `VALUE` of the timer increases from 0 towards the preset value at a rate of one unit for each pulse of the time base.
3	An event is generated when the current value has reached the preset value, the timer is reset to 0, and then reactivated. The associated event processing is also triggered, if the event is not masked. If can be deferred, if there is an event processing task of higher or identical priority already in progress.