"Calibration expired"--you need to read the DS1644-120 internal data,Then modify the calibration date, and finally rewrite the data to DS1644-120,Calibration has expired before normal display can be restored.
"Low pressure display -0.93 bar"---First you need to read U8(24LC32A),It is a 4KB bin file,All calibration data is stored inside this EEPROM chip,After reading the complete data, you need to prepare a digital pressure gauge,I choose druck-DPI705(You can also choose other similar models),Then refer to "amyk"'s post.
If you still don’t understand, you can contact me(daisizhou#sina.com #->@)
I wish you success, I am a biomedical engineer,Looking forward to communicating with you
By the way, there is also a calibration firmware, I can send it to you if you need it