The Inhibit signal is a sinking output. Hence it has two states: ground and floating. When connected to a sourcing input, proper behavior is seen. When the signal should be +5V, the input supplies +5V and the output is floating, so the signal is at +5V. Similarly, when the signal should be 0V, the output is ground and the input is floating, which makes the signal 0V. If you are connecting a multimeter to the Inhibit of the UMI, you will need to add a pullup resistor to see a 0-5V swing. For more information, I recommend looking at this link.
Regards,
Ryan M
Applications Engineer
National Instruments
