Disable PXI-6224 pull down resistors

[jtowich]

Can the pull down resistors on the digital inputs of the PXi-6224 be disabled?

[crossrulz]

Not as far as I know.  You shouldn't just let DIO float as that could damage parts when in the transition area.  That's why the pull downs are there.  Would you rather have pull ups?  You can put in something like a 1k pull up resistor and that would swamp out the pull down resistors.  According to the spec, the pull down resistors are 20k minimum, 50k typical.

[jtowich]

In my circuit the input isn't floating, but based on the current that it is drawing the resistor must be close to 20K. That is too low for the circuit and is causing problems. The circuit works with other systems that have no pull down, but I guess with the 6224 the input will need to be buffered or perhaps use an analog input instead. Sure would be nice to be able to disable those resistors.