16-4 Performance Verification Model 6220/6221 Reference Manual
Return to Section 16 topics
Recommended test equipment
Table 16-1 summarizes recommended test equipment specifications as well as typ-
ical suitable models. Ideally, test equipment uncertainty should be at least four times
better than equivalent Model 6220 or 6221 specifications. However, the equipment
listed for the 2nA and 20nA ranges does not quite meet that requirement.
Test equipment connections
For the sake of clarity, only actual signal lines are shown in test equipment con-
nection drawings in this section. To ensure measurement integrity, be sure to use
appropriate triax cables or (where appropriate) coax cables for all connections.
Calculating test limits
The test limits stated in this section have been calculated using only the
Model 622x one-year accuracy specifications, and they do not include test equip-
ment uncertainty. If a particular measurement falls slightly outside the allowable
range, recalculate the new limits based on both Model 622x specifications and
pertinent calibration equipment specifications.
Example limit calculation
The following is an example of how test limits have been calculated. Assume you
are testing the 20mA range using a 20mA output current. Using ±(0.05% + 10μA)
accuracy, the calculated limits are:
Output current limits = 20mA ±[20mA(0.05%) + 10μA]
Output current limits = 19.980 to 20.020mA
Table 16-1
Recommended test equipment
Description Key specifications Manufacturer/model
Digital Multimeter Measure 200nA to 100mA DC, ±100ppm
1
Measure 10V and 100V DC, ±100ppm
1
Measure 100mA AC @ 1kHz and 100kHz
2
Agilent 3458A
Picoammeter
1
Measure 2nA and 20nA DC, ±2000ppm Keithley 6487
Frequency Counter
2
Measure 1kHz sine wave within ±25ppm Any suitable
Test Resistor
2
50Ω, 1/2W composition Any suitable
1. Equipment used to test output current and compliance accuracy of both 6220 and 6221.
2. Equipment used to test wave functions of 6221 only.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com
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