Frequency Verification; Adjustment (Calibration); Equipment For Calibration; Adjustment Process - Tektronix DMM4020 Technical Reference Manual

DMM4020
Technical Reference

Frequency Verification

Use the function generator to apply the frequencies listed in Table 3-8.
Nominal Input
Ampl.
0.1 V
0.1 V
0.1 V
0.1 V
0.1 V
0.1 V

Adjustment (Calibration)

Meter adjustments, or calibration, should be performed at the desired interval, or
whenever a verification test indicates a Meter function is out of tolerance. The Meter
accuracy will stay within specifications only if the adjustment procedure is performed at
regular intervals. A one-year interval is adequate for most applications. The Meter's
accuracy specifications are not valid beyond the one-year interval.

Equipment for Calibration

The required equipment for calibration is the same as the equipment listed in Table 3-1.

Adjustment Process

The Meter adjustment process can either be managed through the front panel of the Meter
or through the RS-232 port.

Front Panel Adjustments

To put the Meter in the calibration mode, remove the CAL seal and press the Cal Enable
button located on the bottom-right side of the front panel with a thin needle.  will
appear in the secondary display with six flashing dashes in the primary display.
To calibrate a function:
1. Push , , , , , or  to start the calibration process. A
2. With a stable input to the Meter, push  to start calibrating the current calibration
The adjustment steps are divided into six areas by six functions. Table 3-9 lists the
calibration steps and indicates the function/command, calibration point, required input
signal with frequency, and a description.
3-12
Table 3-8. Frequency Verification Steps
Range
Freq.
20 Hz 2000 Hz
50 Hz 2000 Hz
1900 Hz 2000 Hz
19 kHz 20 kHz
195 kHz 200 kHz
1000 kHz 1000 kHz
recommended calibration value will appear in the primary display and continue to
flash until the input is set.
The recommended value can be overwritten by pushing  for
the + or – sign and  through  for the six digits.
point. The displayed value freezes and a flashing star appears in the display. The
Meter automatically makes the necessary adjustment to bring the Meter into
specification. No internal mechanical adjustments are necessary.
90-Day Test Limit
High Low
20.04 Hz 19.96 Hz
50.01 Hz 50.00 Hz
1900.19 Hz 1899.81 Hz
19.0023 Hz 18.9977 Hz
195.024 Hz 194.977 Hz
1000.14 Hz 999.86 Hz
Note
1-Year Test Limit
High Low
20.06 Hz 19.94 Hz
50.01 Hz 50.00 Hz
1900.19 Hz 1899.81 Hz
19.0025 Hz 18.9975 Hz
195.026 Hz 194.975 Hz
1000.16 Hz 999.84 Hz