We're using a PXI-6509 DIO instrument in an application where a number of configured input channels are connected to hardware-under-test that keeps these signals tri-stated most of the time. We've observed that these signals are prone to floating up or down somewhat non-deterministically. We are using the change-detection feature of this instrument to monitor for changes on these signals, but this floating behavior is prone to cause "false" changes.
I am wondering if there might be an easy way to add pull-down (or pull-up) resistors to these input signals? I notice that the PCIe-6509 product has this option built-in. Are there any accessories that might help with this?