There are two types of clock behaviours found on iEM3000 meter series.
iEM3110, iEM3210, iEM3150, iEM3250, iEM3310 and iEM3350
These meters lose the clock immediately after the power interruption as there is no super capacitor or battery built-in. When power is interrupted, the date and time are reset and you must enter configuration mode to configure the clock, if you require time information.
iEM3115, iEM3135, iEM3155, iEM3165, iEM3175, iEM3215, iEM3235, iEM3455/iEM3555, iEM3465/iEM3565, iEM3275, iEM3335, iEM3355, iEM3365, iEM3375, iEM3455, iEM3465, iEM3555 and iEM3565
These meters could keep the clock running for up to 3 days in absence of external power, the meter design uses a built-in super capacitor (not a battery) to power the clock only and keep it running. If power is interrupted for longer than 3 days, the device automatically displays the screen to set Date and Time when power is restored.
Refer to User manual for further information (page 28).