Fluke 8842a instruction manual HIGH-FREQUENCY AC Calibration

Maintenance 6

CALIBRATION

NOTE

To use reference sources that differ from the prompted values, see Storing

Variable Inputs later in this section.

4.After the last range is calibrated, the 8842A begins taking readings in the highest range so that you may verify its calibration. (The CAL annunciator remains on.) To verify the calibration for the other ranges, press the corresponding range button. (Pressing a function button begins the Offset and Gain Calibration procedure for that function.)

5.Repeat steps 2, 3, and 4 for the remaining functions. Note that both 2-wire and 4-wire ohms functions must be calibrated. (The VAC and mA AC functions require calibration only if the True RMS AC option is installed.)

NOTE

(True RMS AC option only.) The VAC and mA AC functions should normally be calibrated using reference sources at 1 kHz (+/-10%). For special applications, performance may be optimized at other frequencies. See Optimizing AC Calibration at Other Frequencies, later in this section.

6.When all functions have been calibrated, exit the calibration mode by pressing the CAL ENABLE switch and attach a calibration certification sticker over the CAL ENABLE switch. (If the True RMS AC option is installed, instead proceed to the High-Frequency AC Calibration procedure which follows.)

6-14. HIGH-FREQUENCY AC CALIBRATION

The High-Frequency AC Calibration procedure calibrates the response of the VAC function from 20 kHz to 100 kHz. If the True RMS AC option is not installed, selecting this procedure results in an error message.

The reference sources used in this procedure should normally be between 90 kHz and 100 kHz. 100 kHz (nominal) is recommended. For special applications, performance may be optimized at other frequencies. See Optimizing AC Calibration at Other Frequencies, later in this section.

To perform High-Frequency AC Calibration, proceed as follows:

1.Ensure Offset and Gain Calibration has been completed for the VAC function.

2.Select the High-Frequency AC Calibration procedure by pressing the HF AC button. The 8842A will display the first prompt (100 mV AC). The "U" in the display indicates the High-Frequency AC Calibration procedure has been selected.

3.Each time the 8842A prompts you for a reference amplitude, apply this amplitude to the HI and LO INPUT terminals, and press the STORE button. When STORE is pressed, the numeric display field blanks while the 8842A performs the necessary calculations. (Do not change the reference source while the display is blank.) The 8842A then displays the next prompt. For reference, all prompts are shown in Table 6-11.

NOTE

To use reference amplitudes that differ from the prompted values, see

Storing Variable Inputs later in this section.

4.After the last range is calibrated, the 8842A begins taking readings in the highest range so that you may verify its calibration. To verify the calibration for the other ranges, push the corresponding range button. The CAL annunciator remains on.

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