Why USB-6008 digital output is not continuous (has some glitches) when set to 1 into a timed loop?

[Rs+Dv]

Hi, I'm new so sorry for mistakes.

I'm managing an USB-6008 with DAQ assistant in LabView 8.2. I'm using a "timed loop" inside which some buttons can be clicked to raise or lower the TTL outputs. When buttons are left on "ON" I would expect a continuous DC output but what I get is that the voltage lowers and then rises again (very quickly) each time the loop starts again. How could I avoid this? Thanks in advance.

[kellam]

Hi Rs+Dv,

The first thing you should check is the mechanical action of your buttons.  On the front panel, right click on the button and go to "Mechanical Action".  The behavior you want corresponds to "Switch When Pressed".  Make sure that is selected option.

-Jeff

[Rs+Dv]

Thanks but unfortunately the mechanical action of the button was already properly set. I also replaced the button with a constant but the result is the same. Even if the digital line is set to 1 by a constant the output turns off for -let's say- 1/10 sec each time the loop is executed. It seems that DAQ assistant re-initializes the USB device at every call. Is there any way to "initialize" the device only once in the VI and then changing only output values (I don't know if this could make sense!)?

[Rs+Dv]

Ok - I found a way to work it out. I uninstalled DAQ base and installed DAQ 9.0.0 (my labview version is 8.2). Then I performed USB-6008 firmware updating as per NI instructions. Now glitches seem to be disappeared.