Use the niDCPower Initialize With Independent Channels VI or the niDCPower_InitializeWithIndependentChannels function to initialize a session.

For any application you write, you must open a session to establish communication with the PXIe-4139 or specified channel(s) by initializing.

Initializing returns an instrument handle with the session configured to a known state. Initialization can take a significant amount of time compared to other NI-DCPower VIs and functions, so you should not include it in a loop when repeatedly acquiring data. Ideally, your program should call Initialize With Independent Channels one time. If the reset parameter is set to TRUE, device channels are reset to the default state, which may include resetting relays.