Our PXI chassis are not "smart chassis" that have status registers that can give you information like whether or not the chassis is on, but you should be able to pull some information from the cards themselves. This will vary from card to card, and from driver to driver. I would recommend starting with the programmer's reference manuals for the drivers (NI-DAQ, NI-VISA, etc.) and the user manuals for the cards. If the cards do respond, you can infer then that the chassis is on.
Ryan Tamblin
Applications Engineer
National Instruments