https://support.casio.com/global/en/wat/manual/3459_en/
https://support.casio.com/storage/en/ma ... qw3459.pdf
The PS indicator means the Power Savings mode is enabled. It will save power by making the display go blank when it's dark. Or something like that. This mode can be disabled. https://support.casio.com/global/en/wat ... jkekf.html
Leaving the watch in a dark location for about one hour between the hours of 10 p.m. and 6 a.m. will cause the display to go blank, and the watch to enter Level 1 power saving. If the watch is left in this condition for six or seven days, the watch will enter Level 2 power saving.
Power Saving Level 1:
Digital display goes blank to save power. The watch can connect with a phone at this level.
Power Saving Level 2:
Digital display goes blank to save power. All functions are disabled.
Recovering from Power Saving Operation
Use one of the operations below to exit power saving.
Press any button.
Move the watch to a bright location.
Trigger auto light by angling the watch towards your face.