Keithley 2500 - Recommended Test Equipment; Verification Limits

1-4 Performance Verification Model 2500 Service Manual
Recommended test equipment
Table 1-1 summarizes recommended verification equipment and pertinent specifications.
You can use alternate equipment as long as that equipment has specifications at least as
good as those listed in Table 1-1. Keep in mind, however, that test equipment uncertainty
will add to the uncertainty of each measurement. Generally, test equipment uncertainty
should be at least four times better than corresponding Model 2500 specifications.
NOTE The Calibrator/Source listed in Table 1-1 does not quite meet the recommended
four times better uncertainty for 19 µ A to 19mA output values. Factory calibra-
tion uses a transfer standard technique that yields uncertainties better that 4:1
for all calibration points.
Verification limits
The verification limits listed in this section have been calculated using only the
Model 2500 one-year accuracy specifications, and they do not include test equipment
uncertainty. If a particular measurement falls outside the allowable range, recalculate new
limits based on Model 2500 specifications and corresponding test equipment
specifications.
Table 1-1
Recommended verification equipment
Description Manufacturer/Model Specifications
Uncertainty
Ratio
4
Calibrator/Source Keithley 263 DC Current
1
1.9nA:
19nA:
190nA:
1.9 µ A:
19 µ A:
190 µ A:
1.9mA:
19mA
2
:
±0.068%
±0.068%
±0.04%
±0.03%
±0.03%
±0.03%
±0.03%
±0.04%
15:1
6:1
7.6:1
6.75:1
3.4:1
3.4:1
3.4:1
2.6:1
Digital Multimeter Keithley 2001 DC Voltage
3
20V:
200V:
±22ppm
±30ppm
45:1
33:1
1
90-day accuracy specifications at specified output for passive V/R amps mode except as noted.
2
90-day specifications at 19mA output for active amps mode.
3
90-day full-range accuracy specifications.
4
Ratio between test equipment uncertainty and Model 2500 uncertainty.