By default, most TiePie engineering measuring instruments work in scope or block mode. In this mode, the complete measurement is recorded in the instrument's memory. After the full record has been measured, the data is transferred to the computer. The next measurement is started after the data has been processed, therefore there are gaps between the measurements.

Besides working in block mode, some TiePie engineering instruments, like the Handyscope HS3 and Handyscope HS4, support streaming mode. In this mode the measured data is transferred directly to the computer, without using the internal memory of the instrument. This makes it possible to perform continuous measurements without gaps.

Both block and streaming measurements have their advantages and disadvantages. The key features of both modes are listed below.

Block mode (/Scope mode):

	Fast measurements are possible
	Record length is limited by the instrument's memory size

Stream mode:

	Long measurements are possible
	Sample speed is limited by the data transfer rate to computer and the computer speed

In block mode, the next measurement is started after the previous data has been transferred to the computer. This means that there will always be a (small) gap in between the measurements. In streaming mode, no data is missed. All successive data blocks can be connected to form one big measurement.

A disadvantage of the streaming mode, is that the maximum measurement speed depends on the data transfer rate from the instrument to the computer, and on the overall system performance.

In streaming mode, successive measurements will arrive in blocks. Each of those blocks contains "record length" samples and can be connected seamlessly with previous and next data blocks.

The Data collector I/O-object can be used to collect the successive measurements and combine them into one big block of data of up to 20 million samples.

By default, most TiePie engineering measuring instruments work in scope or block mode. There are several ways to set an instrument's mode to stream.

The easiest way to use the streaming mode is to use one of the quick functions: "Transient recorder". When you choose this function, either from the main menu or the toolbar, it will set the selected instrument's mode to "stream". Besides this, for each channel of the instrument a data collector I/O-object is created with a data size of 100000 samples and each data collector is put into a graph.

To manually change the mode of an instrument, use the popup menu of the instrument in the object tree. In the menu, select "Measure mode->Stream" or "Measure mode->Block".

Note: To change the mode of an instrument, the instrument must first be set to pause.

Streaming measurements can be performed with the following TiePie engineering USB oscilloscopes: Handyscope HS3, Handyscope HS4 and Handyscope HS4 DIFF.