30.5.3.2 Procedure - Standard InputThe microcomputer on the I/O board watches the input terminal state at 0.5 millisecond-loop updates and writes the input state to the I/F RAM when I/O is refreshed every 2 millisecond-loop update.
When the digital input filter is set, data for sampling set at the time of I/O refreshing is tracked back, and the result is written in I/F RAM. The value written in I/F RAM is read each time the LT is scanned.
In the [Standard I/O Settings] dialog box, when [Word] is selected for [Type], for 32-bit variables allocated to I/O, the lower 12 bits are used for the LT-3200 Series while the lower 16 bits are used for the LT-3300 Series.
Do not use unused areas of allocated variables (fix to 0). If a value is updated for an unused area (for example, at 20 bit), it is cleared on the next scan.