Transducers for AC voltage are available in several different designs, such as in an enclosure for DIN rail mounting or as a module for 19″rack mounting. There are versions for both rectified mean value and true RMS.
LQT400 - Configurable multi-transducer with 2 analogue outputs
LQT60 Wide - Configurable multi-transducer for all applications
LQT60F – Fast transducer with Profibus and Profinet
LT10U, Configurable transducer for AC voltage and frequency