Specifications

Section 3. CR3000 Measurement Details
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-1
0
1
2
-2000 -1000
0 1000 2000
Input Voltage (mV)
Voltage Measurement Error (mV)
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3
3000-3000
CR10X
CR1000
FIGURE 3.9-2. Comparison of the CR10X ± (0.X% of Full-Scale Range) and CR1000 ± (0.X% of
reading + Offset) voltage measurement accuracy specifications for the (0 to 40)
° C temperature range.
The CR10X accuracy specification for the ±2500 mV input range over the (0 to
40)°C temperature range is ± (0.05% of Full-Scale Range) = ±2.5 mV, where Full-
Scale Range has been defined as 5000 mV for the ±2500 mV input range because
that is the range the A/D conversion must span. The resulting CR10X accuracy
specification equals ± 2.5 mV for the entire ±2500 mV input range over the (0 to
40)°C temperature range, illustrated by the shaded rectangular area in Figure 3.9-2.
The CR1000 accuracy specification for the ±2500 mV input range over the (0 to
40)°C temperature range is ±(0.07% of reading + Offset) where Offset = Basic
Resolution + 1 µV for a differential measurement with input reversal. For a 2500
mV input signal over the (0 to 40)°C temperature range the Basic Resolution is
667 µV, resulting in Offset = 668 µV. The resulting voltage measurement
accuracy over a ±2500 mV input range over the (0 to 40)°C temperature range is a
function of the input voltage as illustrated in Figure3.9-2.
For a 2500 mV input signal over the (0 to 40)°C temperature range, the CR1000
accuracy specification results in ±2.42 mV error which is comparable with the
±2.5 mV for the CR10X. For a 500 mV input signal the specified CR10X
accuracy is again ±2.5 mV, whereas the CR1000 accuracy improves to ± 1.02
mV, which better represents actual instrument performance.
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