©
National Instruments Corporation
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Introduction
This chapter describes the NI 4350/4351 (NI 435
x
) family of
high-precision temperature and voltage meters and describes the optional
software and equipment.
About the NI 435
x
High-Precision DAQ Devices
Thank you for purchasing an NI 435
x
high-precision DAQ device. The
NI 435
x
family consists of high-precision DAQ devices for each of the
following buses: Universal Serial Bus (USB), PXI, and PCI.
The NI 435
x
high-precision DAQ devices feature accurate thermocouple
and DC voltage measurements. You also can take temperature
measurements with resistance temperature detectors (RTDs) or
thermistors, resistance measurements using the built-in precision current
sources, and current measurements using external shunt resistors. You can
use the NI 435
x
with a PC to make the same measurements you would with
standard benchtop instruments such as data loggers and digital
multimeters (DMMs).
The NI 435
x
contains a 24-bit sigma-delta analog-to-digital converter
(ADC) with differential analog inputs. The low leakage construction, along
with analog and digital filtering, provides excellent resolution, accuracy,
and noise rejection. With software-programmable ground-referencing,
you can reference the floating signal without compromising voltage
measurements even if the floating signal is ground-referenced. With
software-programmable open-thermocouple detection, you can quickly
detect a thermocouple that may have broken before or during measurement.
You can measure up to a total resistance of 600 k
Ω
using
the built-in
25
µ
A precision current source on the NI USB-4350, NI PCI-4351, and
NI PXI-4351 and up to 15 k
Ω
with the additional built-in 1 mA precision
current source on the NI PXI-4351 and NI PCI-4351. In addition, the
NI 435
x
devices have programmable TTL-compatible digital I/O (DIO)
for monitoring TTL-level inputs, interfacing with external devices, and
generating alarms.