Because you can have multiple digitizers connected to your computer, you must tell NI-SCOPE which digitizer(s) to communicate with by opening a session to the digitizer or digitizers with an Initialize function.

What Is a Session?

A session establishes a connection between digitizers and your application. After this connection is established, the digitizer(s) can transmit data to your application. Sessions allow the driver to cache previous settings, which greatly improves performance.

How Do You Create a Session?

To create a session, use the Initialize with Options or Initialize functions. These functions return a handle that allows you to communicate with the digitizer(s) using other function calls in your application.

You can create sessions that include multiple instruments of the same model and in the same chassis. This automatically synchronizes all channels of the included instruments, simplifying your test program development and maintenance. To create a session to multiple digitizers, enter the instrument names as a comma-delimited list of strings in the form PXI1Slot3,PXI1Slot4 for the Resource Name input parameter of an Initialize function.

Note    You can only specify multiple instruments of identical model numbers, bus types, channel counts, and onboard memory sizes.

LabVIEW Example—Initializing a Session

C Example—Initializing a Session

niScope_init ("PXI1Slot2", VI_TRUE, VI_TRUE, &vi);

Note   
  • When you run your application, you must use the resource name assigned by Measurement & Automation Explorer (MAX). Find or set the resource name for your digitizers by launching MAX and selecting Devices and Interfaces.
  • Setting the ID Query parameter to TRUE has no effect with NI-SCOPE. NI-SCOPE automatically verifies that the digitizer(s) you initialize are supported—therefore, setting this parameter to TRUE is not necessary.
  • Setting the Reset Device parameter to TRUE resets digitizers during initialization.
Caution   Resetting digitizers may cause wear on the relays, so you should reset only when necessary.