Beginning with firmware version SM3-a-1.03, the Bluetooth timeout setting has been changed. The linked document has barcodes that can be used to set the timeout to a variable length with a range of 0 to 60 minutes. Print the page, then scan Set Minute, 2 digits for the number of minutes, then Set Minute again to complete the programming. You can do the same with Set Second, 2 digits, Set Second to change the number of seconds.

https://dl.waspbarcode.com/kb/scanner/wws550i/wws550ipowerofftimeout.pdf