Fluke 8842a instruction manual Step Displayed Prompt, Step Input, L O W a B L E Error

Maintenance 6

CALIBRATION

2.Each time the 8842A prompts you for a reference source, apply the requested source 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 6-8.

NOTE

The 8842A automatically checks that the reference input is near the value prompted, and displays ERROR 41 if it exceeds a specific tolerance. (See Advanced Features and Special Considerations, later in this section.)

3.After the last input is stored, the 8842A begins taking readings in the 2V range of the VDC function. (The CAL annunciator remains on.) Verify the A/D calibration using the test points in Table 6-9. If you wish to repeat the A/D Calibration procedure, press the A/D button.

Table 6-8. A/D Calibration Steps

STEP

A

B

C

D

E

F

G

H

I

J

K

L

DISPLAYED PROMPT

.0 V DC (short)

-.03 V DC

-1.01 V DC + .99 V DC + .51 V DC

-.51 V DC

-.26 V DC + .26 V DC

+.135 V DC - .135 V DC

-.0725 V DC + .0725 V DC

Table 6-9. A/D Calibration Verification Test

STEP

A

B

C

D

E

F

G

INPUT

0V (short)

-0.03V

+0.03V-0.660V

-0.660V +0.660V -1.970V +1.970V

A L L O W A B L E

ERROR

±2 counts ±2 counts ±2 counts ±3 counts ±3 counts ±4 counts ±4 counts

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