Configure a latch input

A latch input, or a pulse-catching input, captures a fast pulse and holds it for a controller scan. The input filter determines the captured pulse width. For
Micro850
 L50E and
Micro870
 L70E controllers, you can configure certain inputs as latch inputs, set the input filter value, and then configure the rising and falling edge behaviors of each latch input.
TIP:
Latch inputs change states faster than can be detected and cannot normally be detected by the input scan portion of the
Micro800
 controller's scan cycle.
To configure a latch input
  1. In
    Project Organizer
    , expand
    I/O Configurations
    .
  2. Open the embedded I/O configuration page by doing one of the following:
    • Double-click
      Embedded
      .
    • Select
      Embedded
      , and then select the
      Enter
      key.
  3. On the
    <controller-catalog-number Embedded I/O>
     page, select
    Configuration
    .
  4. In the
    Input Latch
     column, select one of the following for each latch input:
    • Select
      Rising
       to detect the pulse on the rising edge of the external input.
    • Select
      Falling
       to detect the pulse on the falling edge of the external input
  5. Select the EII edge direction as needed.
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