Accuracy, Crosstalk | Measurement Specialties PCI-DAS1002 guide

PCI-DAS1002 User's Manual

Specifications

Accuracy

Accuracies are listed for a 200 kHz sampling rate, 100 sample average, single channel operation, a 15 minute warm-up, and operational temperatures within ±2 °C of internal calibration temperature. The calibrator test source high side is tied to Channel 0 In and the low side is tied to AGND.

	Table 2. Absolute accuracy specifications (analog input)

Range		Absolute Accuracy

±10.00 V		±2.5 LSB max
±5.000 V		±2.5 LSB max
±2.500 V		±2.5 LSB max
±1.250 V		±2.5 LSB max
0 to 10.00 V		±2.5 LSB max
0 to 5.000 V		±2.5 LSB max
0 to 2.500 V		±2.5 LSB max
0 to 1.250 V		±2.5 LSB max

Each PCI-DAS1002 is tested at the factory to assure the board’s overall error does not exceed accuracy limits described in Table 2 above.

Table 3. Calibrated accuracy components (in LSB)

Range	Gain Error	Offset Error	DLE	ILE

All ranges	±1.0 max	±1.0 max	±0.75 max	±0.5 max

As shown in Table 3, total board error is a combination of gain, offset, differential linearity and integral linearity error. The theoretical worst-case error of the board may be calculated by summing these component errors. Worst case errors are realized only in the unlikely event that each of the component errors are at their maximum level, and causing error in the same direction.

Crosstalk

Crosstalk is defined here as the influence of one channel upon another when scanning two channels at the maximum rate. A full scale 100 Hz triangle wave is input on channel 1; Channel 0 is tied to analog ground at the 100-pin user connector. The table below summarizes the influence of channel 1 on channel 0 with the effects of noise removed. The residue on channel zero is described in LSB’s.

Table 4. Crosstalk specifications

Condition	Crosstalk	Per channel Rate	ADC Rate

All ranges	2 LSB pk-pk	100 kHz	200 kHz

Noise performance

Table 5 below summarizes the noise performance for the PCI-DAS1002. Noise distribution is determined by gathering 50 K samples at 200 kHz with inputs tied to ground at the user connector.

Table 5. Board noise performance

Range	% within ±2 LSB	% within ±1 LSB	LSBs	LSBrms*

0 to 1.250 V	100%	99%	4	0.61
All other ranges	100%	100%	3	0.45

* RMS noise is defined as the peak-to-peak bin spread divided by 6.6.