Hi Ashtri & Steve,
Yes and no.
Yes, without a battery, using just the power harvested from the NFC field, a tag reader is able to communicate and read out all data just fine. But indeed, the tlogger demo firmware was not designed for a passive operation: it explains the use case of unattended logging and monitoring of the temperature, so that the storage conditions of the product or box it is attached to can be guarded. This requires a battery, so it can operate also when no phone is held nearby.
Later, after days/weeks/months of active monitoring, the quality of the goods can be checked with a single tap; and if needs be, all data remain available on the tag to learn when anomalies occurred, allowing you to remedy your cold chain.
If you don't require active logging, you can implement your own firmware and fully customize the behavior of the NHS3100 IC.
Kind regards,
Dries.