PC is not able to detect chassis/ Detection is very unstable

[HelloHelloHello]

Yes! I disabled the 'USB selective suspend setting' already

[JÞB]

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@HelloHelloHello wrote:

Yes! I disabled the 'USB selective suspend setting' already

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At that point I would start suspecting an intermittant problem with either the UBS cable (cracked conductor) or a bent pin on the connector itself.  I have to ask: "have you tried changing cables and are you using a good quality one with ferrites and decient shielding?

[HelloHelloHello]

I used the one that came along with the chassis itself. USB cable with locking screw: 780534-01. When the problem came up, I changed the cable to a new one (Same type) but the problem is not solved. 

[Captain_K]

Just to recap what we’ve tried:

USB port works with other hardware

Different USB port

Different Computer (make sure DAQmx is installed on the other computer you’re using for testing)

Removed all modules

Changed Windows power settings

Tried different USB cable

Is the setup in an electrically noisy environment?

At this point, it might be worth considering sending the chassis in for repair. How old is the chassis?

[JÞB]

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@Captain_K wrote:

Just to recap what we’ve tried:

USB port works with other hardware ( PC / Hub eliminated as trouble)

Different USB port (Specific Port eliminated)

Different Computer (make sure DAQmx is installed on the other computer you’re using for testing) (Dup elimination of avove)

Removed all modules (Faulty module eliminated)

Changed Windows power settings (OS settings shown correct)

Tried different USB cable (Bad Cable eliminated)

Is the setup in an electrically noisy environment?

At this point, it might be worth considering sending the chassis in for repair. How old is the chassis?

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Add,

USB Hub Exterally powered (make and model? Some of the cheap ones have poor power filtering)

USB Cable has ferrites (Noise Reduction applied)

USB Connector secured to chassis with captive screw (Mechanical damage protection in place)

Results - Still intermittant USB Disconnects

Matt is likely onto something.  Time to get that chassis to a shop.

BUT FIRST, lets eliminate other possible environmental factors.  We have a wild intermittant issue here and those can often be caused by improper installation and / or maintenance

Check:

• Chassis Temperature (Compare to operating spec)
• Chassis installation (Recommended airflow available?)
• Chassis cleanliness (Dust, Dirt, Debris removed)
• System Grounding (Ground loop currents on USB Shield are bad bad bad!)
• ESD protection (Tell me you do not have this installed on a metal work surface in a room with carpeting on the floor! Please, if you are getting static shocks from the doorknobs - that is Bad Bad Bad too)

In other words, go through the installation guide front matter carefully!  You know, all those warnings and cautions almost everybody skips over in order to get to the "useful" part of the manual.  Yes, I've been guilty of doing it myself too