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CALIBRATION
6
6-13
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 DISPLAYED PROMPT
A .0 V DC (short)
B - .03 V DC
C - 1.01 V DC
D + .99 V DC
E + .51 V DC
F - .51 V DC
G - .26 V DC
H + .26 V DC
I + .135 V DC
J - .135 V DC
K - .0725 V DC
L + .0725 V DC
Table 6-9. A/D Calibration Verification Test
STEP INPUT A L L O W A B L E
ERROR
A 0V (short) ±2 counts
B -0.03V ±2 counts
C +0.03V-0.660V ±2 counts
D -0.660V ±3 counts
E +0.660V ±3 counts
F -1.970V ±4 counts
G +1.970V ±4 counts