Current Readback Accuracy; 5A Range Readback Accuracy; Compliance Current Accuracy Limits - Keithley 2303 Service Manual

Table 1-4

Compliance current accuracy limits

Model 2303 compliance
current setting
1.000A
2.000A
3.000A
4.000A
5.000A

Current readback accuracy

Follow the steps below to verify that Model 2303, 2303B, or 2303-PJ current readback accu-
racy is within specified limits. The test involves setting the output current to specific values as
measured with a resistor and precision digital multimeter.

5A range readback accuracy

1.
2.
3.
4.
5.
Compliance current limits
(1 Year, 18°C-28°C)
0.993 to 1.007A
1.992 to 2.008A
2.990 to 3.010A
3.989 to 4.011A
4.987 to 5.013A
With the power off, connect the digital multimeter and characterized 1Ω resistor to the
Model 2303 OUTPUT SOURCE terminals, as shown in Figure 1-3. Be sure to observe
proper polarity (SOURCE + to INPUT HI; SOURCE - to INPUT LO). Also be sure to
use 4-wire connections to the resistor terminals.
Select the multimeter DC volts measuring function, and enable auto-ranging.
Select the 5A readback range. Also make sure actual current readings are displayed.
Turn on the Model 2303 output.
Verify 5A range current readback accuracy for the currents listed in Table 1-5. For each
test point:
• By changing the output voltage, adjust the current to the correct value, as determined
from the multimeter voltage reading and characterized resistance value. When setting
the voltage, be sure to set the compliance current to 5A.
• Note that it may not be possible to set the output current to the exact value. In that case,
set the current to the closest possible value, and modify reading limits accordingly.
• Allow the reading to settle.
• Verify that the actual Model 2303 current reading is within the limits given in the table.
Performance Verification 1-9