Keysight E1412A, Service Manual

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102 Keysight E1412A Digital Multimeter Service Guide
E1412A Multimeter Specifications 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
shows the range error applied to the multimeter's 24-hour dc voltage
specification.
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.
% of input error =
ppm of input error =
Error Example
Assume that a 5Vdc signal is input to the multimeter on the 10 Vdc range.
Compute the total measurement error using the 90-day accuracy specifications:


(0.0020% of r 0.0005% of range).
Reading error= 0.0020% x 5Vdc = 100mV
Range error= 0.0005% x 10Vdc = 50mV
Total error= 100mV + 50mV = ±150mV
= ± 0.0030% of 5Vdc
= ± 30 ppm of 5Vdc
Range Input Level
Range Error
(% of range) Range Error
Voltage
10Vdc 10Vdc 0.0004 
40

V
10Vdc 1Vdc 0.0004 
40

V
10Vdc 0.1Vdc 0.0004 
40

V
Total Measurement Error
Input Signal Level
--------------------------------------------------------------
X 100
Total Measurement Error
Input Signal Level
--------------------------------------------------------------
X 1 000 000
 