Technical data

Calibrating and Adjusting 3
4000 X-Series Oscilloscopes Service Guide 67
User Calibration
Perform user-calibration:
• Every two years or after 4000 hours of operation.
• If the ambient temperature is >10° C from the calibration
temperature.
• If you want to maximize the measurement accuracy.
The amount of use, environmental conditions, and
experience with other instruments help determine if you
need shorter User Cal intervals.
User Cal performs an internal self- alignment routine to
optimize the signal path in the oscilloscope. The routine uses
internally generated signals to optimize circuits that affect
channel sensitivity, offset, and trigger parameters. Disconnect
all inputs and allow the oscilloscope to warm up before
performing this procedure.
Performing User Cal will invalidate your Certificate of
Calibration. If NIST (National Institute of Standards and
Technology) traceability is required perform the procedures
in Chapter 2 in this book using traceable sources.
To perform User Cal
1 Disconnect all inputs from the front and rear panels,
including the digital channels cable on an MSO, and allow
the oscilloscope to warm up before performing this
procedure.
2 Press the rear-panel CAL button to disable calibration
protection..
3 Connect short (12 inch maximum) equal length cables to
each analog channel’s BNC connector on the front of the
oscilloscope. You will need two equal- length cables for a