31.5.3.2 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 [Integer] is selected for [Type], for 32-bit variables allocated to I/O, the lower 12 bits are used for the LT-3200 Series, the lower 16 bits are used for the LT-3300 Series, the lower 20 bits are used for the LT4000 Series (DIO model) and the lower 12 bits are used for the LT4000 Series (analog model).
Do not use unused areas of allocated variables (fix to 0). If a value is updated for an unused area (for example, bit 30), it is cleared on the next scan.