Daq system with usb 6009

[Redbull]

Hello All
I have a Daq system with usb 6009 that sometimes work properly and some time not. I don´t know if is noise incoming from my hardware or a problem with the software, but when my charts begin to osscilate only with stop labview and restarting the application the problem is solve.
I´m using a daqmxbase start task.vi to open the task, inside a while loop i get my data by means of one daqmxBase read for analog data and another daqmxbase read for digital data and when the while loop ends I use daqmxbase stop task to close the task. Is this correct or i have to use others daqmxbase vi´s to open and close thes tasks.
Thank you very much

[Redbull]

Additional Info:
I´m adcquiring data for 3 diferential channels of my daq, and i´m using the digital counter of the board too.
The problem happens aleatory, maybe when the system is running for 2 hours or maybe 15 min.
Anyone can help me?.
I´m not sure if i´m initializing well the tasks.
Thank you very much

[Diego_M]

Hi Redbull,

it´s complicated to know what is the reason due to you have this behaviour with your explanation, but I´d try to do some test, for example:

1. To acquire for one channel and evaluate the behaviour and if the behaviour disappears to hook up more signals in order to know how this phenomenon appears.
2. To acquire these signals with other PC.
3. What kind of cable do you have, shielded or ribbon cable??.

Regards

Diego M.

[Redbull]

hello thanks for your answer
i,m triying now with a desktop PC becouse the other PC was a laptop and maybe i´m having problems with the usb ports.
I will keep you informed

[Redbull]

hello Again
In my personal desktop without problems.
Maybe due to I have 2 daqmxbase read running at same time i Have problelms with laptop but not with desktop.
The usb power requeriments can change due to this 2 daqmxbase ????

[Diego_M]

Hi again,

I believe that the power requirements isn´t the reason of this behaviour, due to if your application requires more channels than a single USB data acquisition board can provide, you can use a USB hubs to plug more USB daq board into a single USB port on your computer.

I would check other points in order to know why this board has this behaviour, for example:

1. Noise that you can have closed of your board.
2. Type of signals, I mean, if you signal is very low for example mV, it´s possible to pre-amplifier before acquiring for the USB-board.
3. If you have a PCI-board. Use it to acquire your signals on the computer where you have this behaviour.

Regards

Diego M.