Measurement Computing CIO-DAS16/Jr, Руководство пользователя

Страница: 15 / 19

Chapter 4
Specifications
Typical for 25 °C unless otherwise specified.
Specifications in
italic text are guaranteed by design.
Analog input
Table 1. Analog input specifications
Parameter Specification
A/D converter type AD7800
Resolution 12 bits
Number of channels 8 differential or 16 single-ended, switch selectable
Input ranges ±10 V, ±5 V, ±2.5 V, ±1.25 V, ±0.625 V, 0 to 10 V, 0 to 5 V, 0 to 2.5 V, 0 to
1.25 V, 0 to 0.625 V, fully programmable
Polarity Unipolar/Bipolar, software selectable
A/D pacing Programmable:
ƒ
internal counter or external source (DIG. IN 0 / TRIGGER, rising edge), or
ƒ
software polled
A/D trigger sources External polled gate trigger (DIG. IN 0 / TRIGGER, active high)
A/D triggering modes Digital: Gated pacer, software polled.
(Gate must be disabled by software after trigger event.)
Data transfer Interrupt, DMA or software polled
DMA Channel 1 or 3
A/D conversion time 3 µs
Throughput 120 kHz typical, PC dependant
Absolute accuracy 0.01% of reading ±1 LSB
Differential linearity error ±1 LSB
Integral linearity error ±1 LSB
Differential linearity error ±1 LSB
No missing codes guaranteed 12-bits
Gain drift (A/D specs) ±25 ppm/°C
Zero drift (A/D specs) ±10ppm/°C
Common mode range ±10 V
CMRR @ 60 Hz -72 dB
Input leakage current (@ 25
°
C)
200 nA
Input impedance 10 Meg Ohms min
Absolute maximum input voltage ±35 V
Table 2. Noise distribution (Rate = 1-100 kHz)
Range Average % ±2 bins Average % ±1 bin Average # bins
Bipolar (10 V) 98% 86% 8 bins
Bipolar (5 V) 97% 86% 9 bins
Bipolar (2.5 V) 97% 82% 8 bins
Bipolar (1.25 V) 95% 73% 9 bins
Unipolar (10 V) 95% 79% 9 bins
Unipolar (5 V) 96% 80% 9 bins
Unipolar (2.5 V) 92% 70% 10 bins
Unipolar (1.25 V) 89% 68% 11 bins
15