Voltage Relay Pull-In Detector

I would like any to build a circuit to display the pull-in or drop-out voltage of a relay, any direction to get me started would be appreciated… I would like to use the relay’s tips to hold the display’s value.

What is the coil voltage of the relay being used? 5V? 12? 24V?

generally 0-250 vdc I have access to action packs to convert from 1-10v input or 4-20 ma.