NI PXI-2545 Terminated 4×1 Multiplexer (SP4T) Topology

The following figure represents the NI PXI-2545 in the terminated 4×1 multiplexer topology.

Caution  The terminators on the NI PXI-2545 are rated for 1.5 W at 25 °C. When operating at ambient temperatures greater than 25 °C, a termination power derating applies. Refer the NI PXI-2545 Specifications for more information about termination power derating. Terminators cannot withstand the full rated power of the NI PXI-2545.

Making a Connection

Call the niSwitch Connect Channels VI or the niSwitch_Connect function to connect channels in this topology. If applicable, call the niSwitch Disconnect Channels VI or the niSwitch_Disconnect function to disconnect an existing connection before you call the niSwitch Connect Channels VI or the niSwitch_Connect function.

Note   All channels are disconnected from COM when the NI PXI-2545 is in its power on state. Any input channel not connected to COM is connected to its associated 50 Ω terminator.

The following sequence of tasks illustrates the VI/function calls necessary to make consecutive connections—one between CH 1 and COM and the other between CH 2 and COM:

1. Call the niSwitch Connect Channels VI or the niSwitch_Connect function with parameters ch1 and com.
2. Call the niSwitch Disconnect Channels VI or the niSwitch_Disconnect function with parameters ch1 and com.
3. Call the niSwitch Connect Channels VI or the niSwitch_Connect function with parameters ch2 and com.

When scanning the NI PXI-2545, a typical scan list entry might be ch1->com;. This entry routes the signal connected to CH 1 to COM.