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8842A
Instruction Manual
6-10
6-8. AC Current Test (Option -09 Only)
The following procedure may be used to test the mA AC function:
1. Ensure the 8842A is on and warmed up for at least 1 hour.
2. Select the mA AC function.
3. Connect the AC Current Source to provide a current input to the 2A and LO INPUT
terminals. If an ac current source is not available, the functionality of the 8842A can
be checked at 10 mA by using a Fluke 5200A set at 100V and connected to the
8842A 2A terminal through a 10 kΩ, 2W, 1% resistor.
4. For each step in Table 6-7, set the AC Current Source for the indicated input and
verify that the displayed reading is within the limits shown for each reading rate.
5. Set the AC Current Source to Standby and disconnect it from the 8842A.
Table 6-7. AC Current Test
INPUT TEST LIMITS
STEP
NUMBER
RANGE
CURRENT FREQUENCY MINIMUM MAXIMUM
1 2000 mA 1900.00 mA 1 kHz 1890.40 1909.60
2 2000 mA 100.00 mA 1 kHz 97.60 102.40
6-9. CALIBRATION
CAUTION
To avoid uncalibrating the 8842A, never cycle power on or off
while the CAL ENABLE switch is on.
NOTE
If U220 is replaced, perform the Erase Cal Memory procedure (located
later in this section) before attempting calibration. Failure to do so may
result in an "ERROR 29" on the 8842A front panel display.
The 8842A features closed-case calibration using known reference sources. The 8842A
automatically prompts you for the required reference sources, measures them, calculates
correction factors, and stores the correction factors in the nonvolatile calibration memory.
Closed-case calibration has many advantages. There are no parts to disassemble, no
mechanical adjustments to make, and if the IEEE-488 Interface is installed, the 8842A
can be calibrated by an automated instrumentation system.
The 8842A should normally be calibrated on a regular cycle, typically every 90 days or 1
year. The frequency of the calibration cycle depends on the accuracy specification you
wish to maintain. The 8842A should also be calibrated if it fails the performance test or
has undergone repair. To meet the specifications in Section 1, the 8842A should be
calibrated with equipment meeting the minimum specifications given in Table 6-1.
The following paragraphs first present a basic calibration procedure. This is followed by
a description of advanced features and special considerations, and by a description of
remote calibration using the IEEE-488 Interface.