Measurement Computing miniLAB 1008, User Manual, Page: 53 / 78

miniLAB 1008 User's Guide Functional Details
There are three types of errors which affect the accuracy of a measurement system:
ƒ offset
ƒ gain
ƒ nonlinearity
The primary error sources in the miniLAB 1008 are offset and gain. Nonlinearity is
small in the miniLAB 1008, and is not significant as an error source with respect to
offset and gain.
Figure 4-9
Figure 4-9. Ideal ADC transfer function
shows an ideal, error-free, miniLAB 1008 transfer function. The typical
calibrated accuracy of the miniLAB 1008 is range-dependent, as explained in the
"
Specifications " chapter of this document. We use a ±10 V range here as an example of
what you can expect when performing a measurement in this range.
The accuracy plot in Figure 4-9 is drawn for clarity and is not drawn to scale.
-FS
+FS
Input Voltage
0
4095
Output Code
2048
The miniLAB 1008's offset error is measured at mid-scale. Ideally, a zero-volt input
should produce an output code of 2048. Any deviation from this is an offset error. Fi
shows the miniLAB 1008 transfer function with an offset error. The typical offset
error specification on the ±10 V range is ±9.77 millivolts (mV). Offset error affects all
codes equally by shifting the entire transfer function up or down along the input voltage
axis.
gure
4-10
4-13