Monitor Noise

[DailyDose]

Hey Community.  What I am about to ask isn't necessarily a LabVIEW question.  But because I am the LabVIEW developer and the builder of the test stands, I thought I'd post this question here to see if anyone has run into similar issues and had a solution.  I know many of you build stands and/or are just plain super super smart.

The monitor/keyboard drawers we are using for our stands are apparently creating enough noise that it's creating a small amount of buzz in our readings.  I am using Chassis PXI-1004 and the controller is a PXI-8820.  There's a single display port.  Since the drawer we are using is a dual monitor (I unfortunately cannot direct you to the model of this item), we also use a USB Display adapter that outputs to DVI manufactured by "J5create."

The solution apparently has been to close the drawer and shut them off and just use a regular stand alone monitor which leads me to believe it's the monitors.  Someone suggested dropping the refresh rate of the monitors to 50 HZ.

Does anyone know of Display Port issues or even DVI issues or monitor issues?  Any resolutions to this?  Feel free to answer this in the form of a LabVIEW response so that it's still LabVIEW relevant.

[Minions]

I guess the real question would be, have you been able to quantify that noise?  Is it related to the monitors, the transmission lines, any parallel or adjacent wiring?  Have you worked through a design of Experiments (DoE) to isolate the issue?  Have you tried to unplug the monitor power?  Have you unplugged the DVI input to the monitors or even the CPU output?  So many options...

[DailyDose]

Based on what we've done, it would seem like we've singled it out to the monitors.  The EMI expert was the one who did all the testing and was also the one who suggested to change the frequency of the monitors to 50hz.  I would think it's not the PXI or the controller because he's got a regular monitor connected to it with a display port and is currently having no issues.  So this why we'd assume it's the monitors.  Part of me wonders if the housing for the display drawer is buzzing or something.  Ground it?

[Minions]

It is always a good idea to ground or at least bring the case of the test stand to ground through a resistor.

[JÞB]

We are missing a few details that would help.  A few things do come to mind as potential sources for trouble.

• That USB 2.0 dongle needs 500mA.  You need to have a High Quality externally powered HUB with no USB 1.0 devices attached to that HUB and good quality USB cables WITH FERRITES! to reduce the EMI and run without trouble
• Check the Chassis cooling!  Slot Blockers and filler panels in unused slots are a must haves (Don't even think that they are "Optional".).  Clean the fans and filters regularly.  You are on a Production floor anyhow so acoustics aren't an issue - set the fan to "High" with the switch on the rear panel!   Watch for Installation clearances (See Pg 17)

Check the specs on the Monitors- And, get that manual (Reading it might be useful too) 

Let us know what you find