Event_Latch Function

Introduction

With the Event_Latch function, the Embedded Expert inputs can be configured as event or latch.

Adding a Event_Latch Function

To add an Event_Latch function, proceed as explained in Add an Expert Function.

Event_Latch Function Configuration

To configure the Event_Latch function, click the Event_Latch function:

Event_Latch inputs are used to enable event I/O or latched I/O and they are simple function added under DM72F0 or DM72F1 for input 0 to 3.

Event_Latch input function parameters are:

Parameter	Value	Description	Constraint
Mode	Latch (default)	Latching allows incoming pulses with duration shorter than the controller scan time to be captured and recorded. When input reaches state 1, this state is maintained until the MAST task reads the input.	Use latch inputs in MAST task only.
Mode	Event	Event detection allows to start an event task on edge. The “External task” can be triggered by the rising edge, the falling edge, or both of the input (I0 to I3).	Maximum lead time between the input transition and the External task to start is 0.5 ms (except if a task with a greater priority is running).
Bounce (in ms)	0.002 (default) 0.004 0.012 0.04 0.12 0.4 1.2 4	Filtering value reduces the effect of bounce on a controller input.
Edge	Rising (default) Falling Both	Define the edge detection when the event mode is selected.	In latch mode, this parameter is disabled.

NOTE: Choice of input that supports Run/Stop function is made in Expert I/O Configuration Screen.