If conversion start condition is set to External trigger rising edge/External
trigger falling edge/Level comparison by function AioSetAiStartTrigger,
this status is ON from performing function AioStartAi
to the moment that the start trigger is input.
As the start trigger is input and the conversion starts, this status turns
OFF.
If repeat operation is set by "Repeat", this status turns ON
each time the state becomes to be waiting for the conversion start condition.