National Instruments NI 784xR User Manual

Also see for NI 781xR: User manual User manual

Contents

National Instruments NI 784xR User Manual Manual pdf 25 page image

Chapter 2 Hardware Overview of the NI 78xxRR Series Intelligent DAQ User Manual 2-4 ni.comNI 7831R/7833R OverviewThe NI 7831R/7833R each have eight independent, 16-bit AI channels;eight independent, 16-bit AO channels; 96 bidirectional DIO lines that youcan configure individually for input or output; and a Virtex-II XC2V3000FPGA.NI 784xR OverviewThe NI 784xR each have eight independent, 16-bit AI channels;eight independent, 16-bit AO channels; and 96 bidirectional DIO lines thatyou can configure individually for input or output. The NI PXI-7841R hasa Virtex-5 LX30 FPGA, and the NI PXI-7842R has a Virtex-5 LX50FPGA.NI 785xR OverviewThe NI 785xR each have eight independent, 16-bit AI channels;eight independent, 16-bit AO channels; and 96 bidirectional DIO lines thatyou can configure individually for input or output. The NI PXI-7851R hasa Virtex-5 LX30 FPGA, the NI PXI-7852R has a Virtex-5 LX50 FPGA,the NI PXI-7853R has a Virtex-5 LX85 FPGA, and the NI PXI-7854R hasa Virtex-5 LX110 FPGA.Analog Input (Multifunction R Series Only)You can sample NI 783xR/784xR/785xR AI channels simultaneously or atdifferent rates. The input mode is software configurable, and the inputrange is fixed at ±10 V. The converters return data in two’s complementformat. Table 2-1 shows the ideal output code returned for a given AIvoltage.Table 2-1. Ideal Output Code and AI Voltage MappingInput Description AI VoltageOutput Code (Hex)(Two’s Complement)Full-scale range –1 LSB 9.999695 7FFFFull-scale range –2 LSB 9.999390 7FFEMidscale 0.000000 0000