Just do it!
If your transducer is able to output a 4-20ma current signal the NIO4V will accept it ok. The loop voltage is really irrelevant. If you have been looking at the output from your transducer as an open loop voltage, that will fool you. When you connect the + and - terminals to the analog input module, the voltage across the input will be fine for the NIO4V. Power to the transducer being 24VDC does not mean the output current loop will operate at that voltage. If you want to see what the NIO4V will see, take a 250 ohm resistor and connect it to the current output from your transducer as it the resistor was the module. The voltage across the resistor will be in the range of 1 - 5 VDC. Be sure to not have that resistor installed when you actually connect to the module, it already has one inside.