Now you have really got me intrigued. You guys are suggesting that it requires some serious computational power to create a PDF. The chip on that datalogger is just an STM32 chip.
Heres another link to another version showing the internals.
https://www.walmart.ca/en/ip/PDF-Si...gger-120-Days-Record-Duration/PRD6ATKFFE1OJYF
So my question i suppose is, how does an STM32 have the power to process data into a PDF and allow the user to read that file from its own mass storage?
Clearly it is possible to do it.