Accuracy; Analog Input Dc Voltage Measurement Accuracy; Noise Performance; Settling Time - Measurement Computing USB-1608GX User Manual

USB-1608GX User's Guide

Accuracy

Analog input DC voltage measurement accuracy

Table 2. DC Accuracy components and specifications. All values are (±)
Gain error
Range (% of reading)
±10 V 0.024
±5 V 0.024
±2 V 0.024
±1 V 0.024

Noise performance

For the peak-to-peak noise distribution test, a differential input channel is connected to AGND at the input
terminal block, and 32,000 samples are acquired at the maximum rate available at each setting.
Range Counts
±10 V 6
±5 V 6
±2 V 7
±1 V 9

Settling time

Settling time is defined as the accuracy that can be expected after one conversion when switching from a
channel with a DC input at one extreme of full scale to another channel with a DC input at the other extreme of
full scale. Both input channels are configured for the same input range.
Range 2 µS settling accuracy
(% FSR)
±10 V 0.1251
±5 V 0.0687
±2 V 0.0687
±1 V 0.0687

Analog input calibration

Parameter
Recommended warm-up time
Calibration method
Calibration interval
Calibration reference
Offset error INL error
(µV) (% of range)
915 0.0076
686 0.0076
336 0.0076
245 0.0076
Table 3. Noise performance specifications
LSBrms
0.91
0.91
1.06
1.36
Table 4. Input settling time specifications in µS, typical
4 µS settling accuracy
(% FSR)
0.0031
0.0031
0.0031
0.0031
Table 5. Analog input calibration specifications
Specification
15 minutes min
Self-calibration (firmware)
1 year (factory calibration)
+5 V, ±2.5 mV max. Actual measured values stored in EEPROM.
Tempco: 5 ppm/°C max
Long term stability: 15 ppm/1000 hours
Absolute
accuracy at
Full Scale
(µV)
4075
2266
968
561
17
Specifications
Gain Offset
temperature temperature
coefficient coefficient
(% reading/°C) (µV/°C)
0.0014 47
0.0014 24
0.0014 10
0.0014 5
9 µS settling accuracy
(% FSR)
0.0015
0.0015
0.0015
0.0015