Accuracy Specifications - Agilent Technologies 34420A User Manual

Total Measurement
Error Example
Chapter 8
To Calculate Total Measurement Error
Understanding the " % of range" Error. The range error compensates
for inaccuracies that result from the function and range you select. The
range error contributes a constant error, expressed as a percent of range,
independent of the input signal level. The following table ilustrates the
range error applied to the meter's 24-hour dc voltage specification.
Range Input Level
10 V
10 V
10 V
Total Measurement Error. To compute the total measurement error,
add the reading error and range error. You can then convert the total
measurement error to a "percent of input" error or a
"ppm (part-per-million) of input" error as shown below.
Total Measurement Error
% of input error =
Total Measurement Error
ppm of input error =
Assume that a 5 Vdc signal is input to the meter on the 10 Vdc range.
To compute the total measurement error using the 90-day accuracy
specifications: ±(0.0020% of reading + 0.0004% of range).
Reading Error = 0.0020%
Range Error = 0.0004%
Total Error = 100 V + 40 V =
± 140 V
=
% of input error
5 V
±
ppm of input error =
282
Range Error
(%of range)
10 V 0.0001
1 V 0.0001
0.1 V 0.0001
Input Signal Level
Input Signal Level
5 V = 100 V
10 V = 40 V
±
V
140
= ± 0.0028% of 5 V
100
140 V
1,000,000 =
5 V
Range Error
Voltage
10 V
10 V
10 V
100
1,000,000
±
28 ppm of 5 V