User manual

PicoScope 6000 Series Programmer's Guide 17

3.5.4

Streaming mode

Streaming mode can capture data without the gaps that occur between blocks when

using block mode.

With USB 2.0 it can transfer data to the PC at speeds of at least 13.33 million samples

per second (75 nanoseconds per sample), depending on the computer's performance.

With USB 3.0 this speed increases to 78 million samples per second (12 nanoseconds

per sample). This makes it suitable for high-speed data acquisition, allowing you to

capture long data sets limited only by the computer's memory.

Aggregation. The driver returns aggregated readings while the device is

streaming. If aggregation is set to 1 then only one buffer is returned per channel.

When aggregation is set above 1 then two buffers (maximum and minimum) per

channel are returned.

Memory segmentation. The memory can be divided into segments to reduce the

latency of data transfers to the PC. However, this increases the risk of losing data if

the PC cannot keep up with the device's sampling rate.

See Using streaming mode for programming details.

3.5.4.1

Using streaming mode

This is the general procedure for reading and displaying data in streaming mode using

a single memory segment:

1. Open the oscilloscope using ps6000OpenUnit.

2. Select channels, ranges and AC/DC coupling using ps6000SetChannel.

3. Use the trigger setup functions ps6000SetTriggerChannelConditions,

ps6000SetTriggerChannelDirections and ps6000SetTriggerChannelProperties to

set up the trigger if required.

4. Call ps6000SetDataBuffer to tell the driver where your data buffer is.

5. Set up aggregation and start the oscilloscope running using ps6000RunStreaming.

6. Call ps6000GetStreamingLatestValues to get data.

7. Process data returned to your application's function. This example is using Auto

Stop, so after the driver has received all the data points requested by the

application, it stops the device streaming.

8. Call ps6000Stop, even if Auto Stop is enabled.