Thank you for your question, unfortunately it is not possible to get continuous streamed data with the ADC-212. It operates in two modes single data reading when the operating system on you PC controlls the samples requests (this is only suitable when collecting data at 1 per ms fastest) or block mode where it collects the data quickly and fills the units onboard buffer. The limitation here is that the maximum number of samples is restricted by the buffer size. When the buffer is full or the required number of samples have been collected then they are downloaded. To download the ADC-212/3 full buffer it would take 1.28 seconds, at 100kHz download, then the unit needs to rearm.
The maximum time period that you can sample for can be calculated number of samples * time interval. Picolog 'Fast Block' mode is the usual method.