Doric Instruments 1000 Pro Series Digital Panel meters are suitable - Manual (Page 9)

8
1000-FREQ
The Ac frequency meter is capable of measuring the frequency of
an Ac voltage of up to 1kHz throughout an input voltage range of
199.9mV to 600Vac. The voltage range of the frequency being
measured is selected by connecting the input to the proper screw
terminal located at the rear of the unit. See page 5.
Input Voltage Accuracy Resolution
199.9mV to 600VAC
0 to 1kHz
0.5% 1Hz