You can get the .pdf manual here. Pressing “>>” should get it to display spindle RPM. Unfortunately, that’s all you can get it to display since its password protected. ;-(
2023-05-25 Edit
OOPs - you apparently can also get it to display "Set Frequency" by pressing “>>” again. Section 6.6 of the manual shows what it could be configured to display with the password. (Speed must be the “Customized Display Value”.)