The E4991B has the built-in clock that keeps track of the date and time. This clock is used for the following functions.
To display the current date and time in the instrument status bar at the lower part of the screen
To write date and time information when saving internal data
Below are the options to change the Date & Time of E4991B:
Double-click the clock at the bottom right of the taskbar. Click on the Change date and time settings. The Date and Time dialog box appears. Click on the Change date and time settings button. Perform the desired changes.
System > Misc Setup > Clock Setup > Set Date and Time....Similar to the earlier option, the Date and Time dialog box appears. Click on the Change date and time button. Perform the desired changes.