Keithley SourceMeter 3A 2420, Руководство по обслуживанию

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Performance Verification 1-13
* See separate procedure for 3A range. DMM voltage reading is same as sourced current.
1
Specifications valid for continuous output currents below 105mA. For operating above 105mA on the 1A range
for >1 minute, derate accuracy 10%/100mA above 105mA. For operating above 105mA on the 3A range for >1
minute, derate accuracy 10%/300mA above 105mA.
Current measurement accuracy
Follow the steps below to verify that Model 2420 current measurement accuracy is within
specified limits. The procedure involves applying accurate currents from the Model 2420 current
source and then verifying that Model 2420 current measurements are within required limits.
10
µ
A to 1A range accuracy
1. With the power off, connect the digital multimeter to the Model 2420 INPUT/OUTPUT
jacks, as shown in Figure 1-2.
2. Select the multimeter DC current function.
3. Set the Model 2420 to both source and measure current by pressing the SOURCE I and
MEAS I keys, and make sure the source output is turned on.
4. Verify measure current accuracy for the 10
µ
A-1A range currents listed in Table 1-6. For
each measurement:
• Select the correct source range.
• Set the Model 2420 source output to the correct value as measured by the digital multimeter.
• Verify that the Model 2420 current reading is within the limits given in the table.
NOTE
It may not be possible to set the current source to the specified value. Use the closest
possible setting, and modify reading limits accordingly.
5. Repeat the procedure for negative calibrator currents with the same magnitudes as those
listed in Table 1-6.
6. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.
NOTE Test currents above 105mA cannot be maintained longer than 1 minute without
affecting accuracy. See derating information in Note 1 under Table 1-5.
Table 1-5
Output current accuracy limits
Model 2420
source range
Model 2420
output current setting
Output current limits
(1 year, 18°C-28°C)
10
µ
A
100
µ
A
1mA
10mA
100mA
1A
3A*
10.0000
µ
A
100.000
µ
A
1.00000mA
10.0000mA
100.000mA
1.00000A
3.00000A
9.9947 to 10.0053
µ
A
99.949 to 100.051
µ
A
0.99946 to 1.00054mA
9.9935 to 10.0065mA
99.914 to 100.086mA
0.99843 to 1.00157A
1
2.99553 to 3.00447A
1