We have a test system with PXI-6541 digital waveform card that has never been used. I'm helping the test person debug the Labview program.
It appears the channels being used as inputs always have the 50 ohm driver active. In the product specification in the Generation Channel table, I see reference to "Data channel driver enable/disable control - Per Channel - Software Selectable". So does that mean if we need a DIO to be input only with high impedance the driver needs to be disabled? I am new to Labview so am not entirely clear on how the person is setting up the DIO as inputs and outputs but he described it as simply assigning a channel as IN will turn off the associated driver.
Could you share a screenshot of the code you're trying to debug, or even the VI itself?
Referring to the NI Digital Waveform Generator/Analyzer Help, it states that "the input impedance of the NI 6541/6542 is high impedance. In the same document you were referring to, the NI PXI/PCI-6541/6542 Specifications it lists that the input impedance of the 6541, depending on the rev of the card, at either 10 kOhms or 50 kOhms.
If a channel has been set to input, the niHSDIO driver should set the input impedance of that channel to be high impedance. Furthermore, the channel power-on state is high impedance with the drivers disabled.
How are you measuring or how do you know that the channels being used as inputs have the 50-ohm driver active?