2 Front-Panel Operation
52 Keysight 34420A User’s Guide
To Select an Input Channel
For voltage measurements, you have two independent input channels.
–Pressing   toggles the display between Channel 1 and Channel 2.
– Pressing     (Scan) creates an alternating Channel 1 and Channel 2 
display. Press   again to cancel.
Scan mode alternates between input channels every 3 seconds or every 
measurement, whichever is longer. If you are using the scan mode, turn off all 
the input filters (both digital and analog), see page 68.