Dynamic characteristics, Stability, Explanation of analog output specifications – National Instruments PCI-1200 User Manual

Page 75: Digital i/o

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Appendix A

Specifications

© National Instruments Corporation

A-7

PCI-1200 User Manual

Power-on state........................................ 0 V

Dynamic Characteristics

Settling time to full-scale range (FSR) .. 5 µs

Stability

Offset temperature coefficient ............... ±50 µV/

° C

Gain temperature coefficient.................. ±30 ppm/

° C

Explanation of Analog Output Specifications

Relative accuracy in a D/A system is the same as nonlinearity because no
uncertainty is added due to code width. Unlike an ADC, every digital code
in a D/A system represents a specific analog value rather than a range of
values. The relative accuracy of the system is therefore limited to the
worst-case deviation from the ideal correspondence (a straight line), except
noise. If a D/A system has been calibrated perfectly, the relative accuracy
specification reflects its worst-case absolute error.

DNL in a D/A system is a measure of deviation of code width from 1 LSB.
In this case, code width is the difference between the analog values
produced by consecutive digital codes. A specification of ±1 LSB
differential nonlinearity ensures that the code width is always greater than
0 LSBs (guaranteeing monotonicity) and is always less than 2 LSBs.

Digital I/O

Number of channels ............................... 24 I/O (three 8-bit ports;

uses 82C55A PPI)

Compatibility ......................................... TTL

Digital logic levels

Level

Min

Max

Input low voltage

–0.3 V

0.8 V

Input high voltage

2.2 V

5.3 V

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