6
Adjustment and Verification
Performance Verification
Equipment Configuration
1. On the 8508A, select
CLEAR, Pwr Up Dflt to select DCV 1 kV range.
2. Ensure that the calibrator output is set to
STANDBY and configured for Internal
Guard (
EX GRD is deselected).
3. Connect the calibrator to the 8508A as described for Routine Adjustment.
Note
After making the connections allow at least 30 minutes for thermal emfs in
the leads to stabilise.
4. On the calibrator select zero Ω and
OPR to operate the output.
Select
EX SNS.
5. Confirm the 8508A is configured for internal guard (External Guard is deselected) by
checking that the
ExGd legend does not appear on the left hand display.
Procedure
Perform the following sequence for each resistance mode and each range, as listed in
Table 6-10, starting with the 2 Ω range and working up to the 2 GΩ range for the
NormalΩ and NormalΩ LoI resistance modes. Then continue the sequence for the TruΩ
and TruΩ LoI modes, starting with the 2 Ω range and working up to the 20 kΩ range.
Finally complete the sequence for the HiVΩ mode, starting with the 20 MΩ range and
working up to the 20 GΩ range. An input zero operation is performed on each 8508A
range with the calibrator set to zero Ω prior to performing the range verification
measurements. A separate zero operation is required on each range for each resistance
mode.
Note that EX SNS (4-wire) is not available on the 5720A 100 MΩ range, and the 8508-
7000K 1 GΩ standard resistor is used as a 2-wire device with the calibrator 2-wire
resistance zero used for the corresponding zero point. Ensure
4WΩ is deselected on the
8508A when checking the 200 MΩ and 2 GΩ range, range zero, and range gain points.
Warning
The Multimeter can deliver a lethal electric shock when operating in the
High Voltage Resistance mode. Voltages up to 240V may appear on the
terminals.
To avoid electric shock when performing the following adjustment
procedures:
• Never touch any lead or terminal unless you are absolutely certain
that no dangerous voltage is present.
• Make sure that signal leads are in a safe condition before you
handle them in any way.
6-43
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