VIEWER: this mode only allow users to see what is going on with no other priviledge.
OPERATOR: this mode allow users to start and stop acquisitions; but does not allow user to change default settings.
EXPERT: this mode allow users to start and stop acquisitions and change default settings.
The input is case sensitive.
Only authorized experts are allowed to make changes on defaul settings.
Experts need to set up default settings when first time login
Contact dongqing if need further helps: email@example.com