
Chapter 18 NI 435X Devices
DAQ Hardware Overview Guide 18-2 www.ni.com
switch on the ground-referencing, CH− is referenced to analog ground
through a 10 MΩ internal resistance. If you switch on open-thermocouple
detection, CH+ is connected to +2.5 V through a weak pull-up
of 10 MΩ internal resistance. You can set ground-referencing and
open-thermocouple detection on a per channel basis. Table 18-1
summarizes the analog input ranges for the 435X devices.
NI 435
X
Data Acquisition
The NI 435X devices can perform single-channel data acquisition and
multiple-channel data acquisition. You select a single analog input channel
and input range setting for single-channel data acquisition. The device
performs a single A/D conversion on that channel for every sample
interval.
For multiple-channel scanned data acquisition, the NI 435X scans a set of
analog input channels, all with the same input range. In this method, a scan
sequence indicates which analog channels to scan. The length of this scan
sequence can be one to eight for the NI 4350 for PCMCIA and one to 16
for the NI 435X for ISA, USB, PCI, and PXI. Table 18-2 summarizes the
ranges for the 435X device data acquisition.
Table 18-1.
Analog Input Ranges for the 435
X
Devices
Range Analog Input
Vo l t s
±
0.625
±
1.25
±
2.5
±
3.75 +7.5
±
15
Ohms
(25 µA)
25 k 50 k 100 k 150 k 300 k 600 k
Ohms
(1 mA)
625 1.25 k 2.5 k 3.75 k 7.5 k 15 k
Table 18-2.
Ranges for 435
X
Device Data Acquisition
Notch
Frequency (Hz)
Number
of Channels
Reading
Rate (Hz)
Harmonics of Noise
Frequencies Filtered (Hz)
10 1 10 10
50 1 50 50
60 1 60 60
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