When the input is activated, the input signal is copied from the physical input to the input flag.
The input flag is held high for the input hold time period, even if the physical input is removed. This function ensures that the controller recognizes the input, even if the input signal was only ON for a very short time, and the physical input has disappeared before the controller scans the input channel.
(In the case of a combined input / output module, the input flag is the same flag as is used for output status monitoring when the channel is configured as an output.)
(See also: Input mode setting.)