Proper Power Cycling

[Bernadette]

We have a fixture that uses a PC and a few DAQ modules.  There are separate power switches for the PC and the rest of the fixture.  My question is - is it best to have the PC fully powered on before turning on the power to the DAQ modules?

[Hooovahh]

Windows and NI are getting better about this, but the default in my mind is to have the DAQ hardware powered up at the same time, or before the PC.

Many devices are plug and play in that they can be recognized as power is added or removed.  But that is sorta like plugging in and unplugging PCI cards as the PC is on.  So for me I have a MXI interface to a PXI chassis.  I have the PC and chassis plugged into the same UPS that turns them both on at the same time.

[crossrulz]

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@Bernadette wrote:

We have a fixture that uses a PC and a few DAQ modules.  There are separate power switches for the PC and the rest of the fixture.  My question is - is it best to have the PC fully powered on before turning on the power to the DAQ modules?

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What are the DAQ modules?  It mostly depends on bus that is being used.

USB doesn't really care.  Ethernet will care even less.

PCI and PXI, it matters a lot.  Always have the PXI chassis on before you turn on the PC and do not turn off the power until the PC is completely shut down.  Really bad things can happen.

[Robert.W]

Assuming PXI as the interface, the chassis should be powered on when you boot the PC.  During boot, the PC needs to properly find/enumerate the modules.  Some MXI flavors will power on the connected chassis when you power on the PC, but they don't all do that.

robert