HP E1328A, Руководство по обслуживанию, Страница: 56 / 70

DAC Accuracy
Calculations
For the HP E1328A DAC performance verification tests, accuracy is
defined for DC Voltage and DC Current outputs using the 1-year
specifications in Appendix A - Specifications of the HP E1328A User’s
Manual. The assumed test conditions are:
•
1 year since calibration
•
At least 1-hour warmup
•
Temperature
±
5°C different than calibration temp
•
Calibration ON state (CALx:STAT ON) for each channel
•
Same load as at calibration
DC Voltage
Accuracy Equations
From Appendix A of the HP E1328A User’s Manual, DC Voltage
Accuracy (1-year) = Ac Temperature Coefficient =
±
[(.3% of
110 mV) + (0.01% .667 mV)/°C]. For 1-year
specifications and
±
5°C difference from calibration temperature:
Example: Calculate DC Voltage Output Accuracy
For a 5.0 V dc output:
DCV Accuracy (1-year) =
±
[.0035 x 5.0 + .11334] =
±
0.13084V. Thus,
for a 5.0 V output, the Upper Limit value in Table 4-2 = 5.13084 V and the
Lower Limit value = 4.86916 V.
DC Current
Accuracy Equations
From Appendix A of the HP E1328A User’s Manual, DC Current
Accuracy 1-year) = Ac Temperature Coefficient =
±
[(.3% of
220
µ
A) + (.01% of 1.33
µ
A)/°C]. For 1-year
specifications and
±
5°C difference from calibration temperature:
Example: Calculate DC Current Output Accuracy
For a 10.0 mA dc output, Accuracy (1-year) =
±
[.0035 x 10.0 x 10
-3
+
226.65 x 10
-6
) =
±
0.26165 mA. Thus, for a 10.0 mA output, the Upper
DC Voltage Accuracy (in Volts) =
±
(.0035 x .11334),
where output is in Volts.
DC Current Accuracy (in A) =
±
(.0035 x 226.65 X 10
-6
),
where output is in Amps.
56 Calculating D/A Converter Accuracy Appendix A