Bizarre Frequency calculated when VT is unplugged

This happens when I unplugged the VT. I believe the same will happen when the power is out and I run IoTaWatt through a UPS.

Can we skip the frequency calculation and zero out the frequency when the voltage is under a certain threshold?

The problem is that sample power, and the whole way everything is scheduled, is based on the line frequency. Sure we could hack it to try to sense when there is no voltage, but it’s a power monitor. It’s whole reason for being is to measure power. So I recommend not using a UPS, just let it shut down. It boots back up in seconds

Also frequency is not a very useful measure (unless you are in the control room managing the whole grid).

Would like to monitor the frequency of the backup generator, but it may not be useful since it’s an inverter generator.

When no voltage is detected the frequency seems to be random. I would think some value as undefined or invalid or zero is better than random.

In that situation I guess you are managing the whole grid (just on a smaller scale).