[NI PCI-6509] Read Digital Input is always showing "true"

[amkind]

Hi All,

I have installed a NI PCI-6509 DAQ and am testing it using the sample source codes (ReadDigitalChannel) provided by the NI-DAQmx installer DVD. I am using Visual Studio 2013 Professional with NI-DAQmx 15.0.

When I run this sample code, I find that "Dev1/port0/line0:7" always reads "true" on all lines even though there is no input provided.

I was expecting the values to be read "false" as there is no input to the DAQ. Is this normal or am I missing something?

thanks

[Dennis_Knutson]

There is a pull-up on each input so you should get a true.

[amkind]

Thanks Dennis!

I got it working by doing the following:

- Ensured that ports that are not used (at the connector block end) are screwed up tight - so there is no leackage currents at the scriew joints

- I am using R1005050 connection cable that was earlier not having a tight fit with the DAQ card. Ensured that it is fitted properly.