Measurement-computing miniLAB-1008 Instrukcja Użytkownika Pobierz pdf (Strona 23)

miniLAB 1008 User's Guide Functional Details

The accuracy plots in Figure 3-10 are drawn for clarity and are not drawn to scale.

-FS

+FS

Input Voltage

4095

Offset=9.77mV

Ideal

Actual

Output Cod

9.77mV

2048

Figure 3-10. ADC transfer function with offset error

Gain error is a change in the slope of the transfer function from the ideal, and is typically expressed as a

percentage of full-scale. shows the miniLAB 1008 transfer function with gain error. Gain error is

easily converted to voltage by multiplying the full-scale (FS) input by the error.

Figure 3-11

Figure 3-11. ADC Transfer function with gain error

The accuracy plots in Figure 3-11 are drawn for clarity and are not drawn to scale.

-FS

+FS

Input Voltage

4095

ctual

Ideal

Output Code

Gain error=+0.2%, or +20 m

Gain error=-0.2%, or -20 mV

2048

For example, the miniLAB 1008 exhibits a typical calibrated gain error of ±0.2% on all ranges. For the ±10 V

range, this would yield 10V × ±0.002 = ±20 mV. This means that at full scale, neglecting the effect of offset for

the moment, the measurement would be within 20 mV of the actual value. Note that gain error is expressed as a

ratio. Values near ±FS are more affected from an absolute voltage standpoint than are values near mid-scale,

which see little or no voltage error.

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Measurement-computing miniLAB-1008 Instrukcja Użytkownika Strona 23