Keithley 2010, Service Manual, Page: 17 / 134

Verification limits
The verification limits stated in this section have been calculated using only the Model 2010
one-year accuracy specifications. All ranges do not include the verification equipment’s
uncertainty. If a particular measurement falls slightly outside the allowable range, recalculate
new limits based on both Model 2010 specifications and pertinent calibration equipment
specifications.
Example reading limit calculation
The following is an example of how reading limits have been calculated:
Assume you are testing the 10V DC range using a 10V input value. Using the Model 2010
one-year accuracy specification for 10V DC of ± (24ppm of r 4ppm of range), the
calculated limits are:
Reading limits = 10V ± [(10V
×
24ppm) + (10V
×
4ppm)]
Reading limits = 10V ± (.00024 + .00004)
Reading limits = 10V ± .00028V
Reading limits = 9.99972V to 10.00028V
Calculating resistance reading limits
Resistance reading limits must be recalculated based on the actual calibration resistance
values supplied by the equipment manufacturer. Calculations are performed in the same manner
as shown in the preceding example, except you should use the actual calibration resistance
values instead of the nominal values when performing your calculations.
Restoring factory defaults
Before performing the verification procedures, restore the instrument to its factory defaults
as follows:
1. Press SHIFT and then SETUP. The instrument will display the following prompt:
RESTORE: FACT
NOTE Pressing either range key toggles the RESTORE selection between USER and FACT.
2. Select FACT, and then restore the factory default conditions by pressing ENTER.
3. Factory defaults will be set as follows:
Speed: medium
Filter: 10 readings
1-4 Performance Verification