Lose connection to USB device

[FlexTor]

Hi All,

I have developed an automated system which is used to calibarate lines scales. These scales are usually between 10mm and 150mm long and have divisions of 0.1mm and lower. I use a camera to determine the edge/position of the divisions. A translation stage (USB) from Physik Instrumente and a high resolution piezo motor to move from each division. A laser interferometer is used to measure the distance the motors have moved(i.e. the distance between divisions).

In the program I have the option for the user to set a start time for the calibration, for example 02:00.

My problem is that by 2 o'clock in the morning the computer has gone into Screen/Power Saver mode. This causes the translation stage from Physik Instrumente to disconnect and causes an error which pauses the program. In the morning when I come back in, the error is on screen and when I press continue the program continues as normal.

So what I'm looking for is some way to deal with this situation. I have tried the following with no success:

Turn off Screen/Power Saver mode - The IT Dept here wont let me since multiple users access this program they have to turn it off for each user.

Turning off the power management in the usb port properties had no effect.

I also tried a subVI that would move the mouse to a position on the screen in hopes that this would stop the computer from entering the power saver mode. Needless to say it didnt work.

Any ideas would be appreciated,

Many Thanks,

Cain

[GabrielaK]

Hi Cain,

just wanted to let you know that I have forwarded your question to our controller specialists. The name of the controller is probably C-867, right? 

I guess this is more an IT related problem so I am not sure if we can really help but we will reply here if we have any suggestions. For now, have a good weekend.

Best regards,

Gabriela

[Don_Phillips]

Boy that takes me back in time...

I once had to code up an application to disable the power modes/ screen savers/ etc on a colleagues computer.

If you can get it installed I think it might work for this case also.

Try it out here:

http://forums.ni.com/t5/LabVIEW/Why-Doesn-t-LabVIEW-Intercept-the-WM-SYSCOMMAND-Windows-Message/m-p/...

Note: no run times required and it is only 3K bytes...

[JÞB]

Turning off the power management in the usb port properties had no effect

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Well, you are definately on to the root cause of the USB failures.  if this is a Windows machine you do need to set the PC Power management options to "never sleep."

I was kind enough to keep the browser bar in the snip so, you can get here.

IT must be made to understand the experiment must go on.  That's why you have a computer- to do work while you are away so you don't need 5 shifts of people to watch the program run.

[GabrielaK]

I agree with Jeff. One remark from a colleague: you could either use the RS-232 connection instead. Or, (but here we are not sure if this really works) use an active USB hub which has it's own power supply.

Regards,

Gabriela

[elrathia]

You might also look here;

(right click on the USB Root Hubs at the bottom to get the properties box)

[SnowMule · Accepted solution]

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@elrathia wrote:

You might also look here;

(right click on the USB Root Hubs at the bottom to get the properties box)

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That's one of the first things I turn off with any machine I encounter.  Causes more problems than its worth.

But it sounds like your problem lies with the machine simply going to sleep after a period of inactivity rather than lower-level power management.